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BACKGROUND OF THE INVENTION
The present invention relates to a micro-reactor device in which a minute of sample material is made to react in a microscopic area and also to a minute sample analysis system which uses the micro-reactor device.
As a method for causing reaction between sample and reactive reagent on a flow basis, a flow injection analysis is generally applied to the sample which is introduced into the reactive reagent and made to react therewith during flow of the sample liquid and to be subjected to a concentration measurement by an optical detection method based on its abasorbance. Details of such methods which details are shown, for example, in Analytical Chemistry, Vol. 50 (1978), pp. 832A-846A or in Analytical Chemistry, Vol. 53 (1981), pp. 20A-32A or in Analytica Chimica Acta, Vol. 78 (1975), pp. 145-157.
SUMMARY OF THE INVENTION
In the case where a liquid feeding pump of a mechanical drive type is used in the above-mentioned flow injection analysis, flow within a flow passage becomes laminar flow having a flow profile 41 as shown in FIG. 2. The laminar flow has such a velocity distribution that the flow has a velocity of substantially zero at its both ends due to the flow resistance of walls 42 and 43 of the passage and has a maximum velocity at its central part. For this reason, there occurs a problem that such a difference in the flow velocity within the passage causes the injected sample to flow through the passage without keeping its original shape. And consequently, band broadening of the injected sample, as a result of mixing with the solution at its front and rear ends thereof, results in a decrease of concentration of the sample liquid and in an increase of volume in the sample.
In this connection, a pressure drop Δp is expressed as a Hagen-Poiseuille law which follows.
Δp=8μ/Qr.sup.4
where μ denotes the viscosity of the liquid, l denotes the length of the passage, Q denotes flow quantity, and r denotes the radius of the passage.
That is, the pressure drop increases inversely proportional to the fourth power of the radius of the passage. For this reason, when a capillary as small as 100 μm or less is used as the passage for the purpose of handling such a very small amount of sample as a nanoliter level, the pressure drop becomes large, which involves another problem of withstanding pressure within the apparatus. That special measure must be take providing a pressure resistive property to the wall material of the passage and also to a coupling part between the passages.
Thus, there have not been so far realized a micro-reactor device wherein a very small amount of sample as minute as nanoliter level is made to react with reactive reagent, as well as a minute sample analysis system which is a combination of the micro-reactor device for pretreatment and an analyzing device suitable for analysis of a very small amount of sample composition such as a capillary electrophoresis device.
In order to solve the above problems, in accordance with the present invention, transfer of sample and reactive reagent in a micro-reactor device is carried out on an electroosmotic flow.
Further, the micro-reactor device is formed on a planar substrate having very narrow grooves.
Furthermore, the micro-reactor device is coupled via a quantitative measuring device with a capillary electrophoresis device.
Electroosmotic flow takes place when application of a voltage across a capillary tube causes electric double layers 51 and 52 formed on the internal surface of the tube to move in the same direction as an electric field established by an applied voltage, as shown in FIG. 3. In this case, the flow profile is a flat flow 53 as shown in FIG. 3. For this reason, sample diffusion is as small as several tenths of that in the case of laminar flow. A velocity u osm of the electro-osmotic flow is expressed by the following equation.
U.sub.osm =keE/zη√c
where, k denotes a constant, e denotes charge quantity of the capillary tube per its unit surface, E denotes applied voltage, z denotes the number of charges in electrolyte, η denotes the viscosity of solution, and c denotes the concentration of the electrolyte.
In this way, since the electroosmotic flow depends on the applied voltage, the concentration of the electrolyte in the solution, and the sign and the quantity of charges on the surface of the capillary tube, control of the quantity of solution to be transferred can be facilitated. Further, the pressure drop caused by the solution transfer is substantially zero.
The capillary electrophoresis is an effective analyzing method having a high separation ability but requires the sample quantity to be as small as the nanoliter level. Thus, for the purpose of preventing a large quantity of sample solution from being introduced from the micro-reactor device into the capillary electrophoresis device, there is provided a quantitative measuring device between the capillary electrophoresis device and the micro-reactor device. As a result, a very small amount of sample can be accurately introduced into the capillary electrophoresis device, and on-line analysis, including the reaction of a very small sample with the reagent and separation of sample compositions, can be performed without subjecting to any dilution and loss.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an arrangement of a minute sample analysis system in which a first micro-reactor device is used in accordance with the present invention;
FIG. 2 shows a flow profile of laminar flow;
FIG. 3 is a flow profile of electroosmotic flow;
FIGS. 4A and 4B show detailed steps in a reagent introduction method;
FIGS. 5A, 5B and 5C show detailed steps in a sample introduction method and in a sample-reagent reaction method;
FIGS. 6A and 6B show detailed steps in an analysis method;
FIG. 7 is a block diagram of an arrangement of a second micro-reactor device in accordance with the present invention;
FIGS. 8A and 8B show a structure of flow passages of the second micro-reactor device; and
FIGS. 9A and 9B show a structure of a passage switching part in the second micro-reactor device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first embodiment of the present invention will be explained with reference to FIG. 1 showing its block diagram.
A minute sample analysis system of FIG. 1 in accordance with the first embodiment of the present invention comprises a micro-reactor device 1, a quantitative measuring device 2, an analyzing device 3, and a controller 4.
More specifically, the micro-reactor device 1 includes a power supply 5 for liquid transfer; power change-over switch 6; passages 7a to 7g; sample quantity measurer 8; a solution reservoir 9; a reactive reagent reservoir 11; platinum electrodes 10, 12, 18 and 22; passage change-over switches 13, 14 and 15; an automatic sample injector 16, a sample reservoir 17, a sample stage 19, a power supply 20 for sample introduction, a waste solution reservoir 21, a reactor 23, and a constant-temperature heat resevior 24. The micro-reactor 1 functions to provide pre-treatment to cause reaction between sample and such reactive reagent as fluorescent reagent.
The power supply for liquid transfer 5, which comprises a high voltage power supply having an output voltage of 0-30 kV, applies a high voltage between the platinum electrode 10 of the solution reservoir 9 and the platinum electrode 28 of the waste solution reservoir 27 of the quantitative measuring device 2, or to between the platinum electrode 12 of the reactive reagent reservoir 11 and the platinum electrode 28 of the waste solution reservoir 27 of the quantitative measuring device 2. An eluting solution within the solution reservoir 9, when the high voltage is applied between the solution reservoir 9 and the waste solution reservoir 27 of the quantitative measuring device 2, is circulated in the form of an electroosmotic flow, caused by the high voltage application, through the passages 7a, 7c, 7d and 7e sequentially in this order. Similarly, a reactive reagent solution within the reactive reagent reservoir 11, when the high voltage is applied to between the reactive reagent reservoir 11 and the waste solution reservoir 27 of the quantitative measuring device 2, is circulated in the form of an electroosmotic flow caused by the high voltage application through the passages 7b, 7c, 7d and 7e sequentially in this order.
The flows of the above eluting and reactive reagent solutions can be controlled with use of the passage change-over switches 13, 14 and 15. Their flow rate can be easily set by controlling the applied voltage. In more detail, the power change-over switch 6 acts to select the voltage application between the solution reservoir 9 and the waste solution reservoir 27 of the quantitative measuring device 2 or the voltage application between the reactive reagent reservoir 11 and the waste solution reservoir 27 of the quantitative measuring device 2. By controlling the applied voltage and the switching time, the amount of reactive reagent introduced into the passages can be readily adjusted. In this connection, each of the passages 7a to 7e was made up of a glass capillary tube (manufactured by GL Sciences company) having an inner diameter of 75 μm and an outer diameter of 375 μm. Further, the passage change-over switches 13, 14 and 15 may be replaced, for example, by a three-way valve.
Sample introduction to the sample quantitative measurer 8 is carried out by means of the power supply 20 for sample introduction applying a high voltage between the platinum electrode 18 of the sample reservoir 17 placed on the sample stage 19 and the platinum electrode 22 of the waste solution reservoir 21. First of all, the automatic sample injector 16 is used to insert a tip end of the passage 7f into the sample reservoir 17 placed on the sample stage 19. Thereafter, the high voltage is applied between the platinum electrode 18 of the sample reservoir 17 and the platinum electrode 22 of the waste solution reservoir 21 so that the sample solution within the sample reservoir 17 flows in the form of an electroosmotic flow caused by the high voltage application through the passages 7f, 8 and 7g sequentially in this order. In this case, the amount of sample solution introduced can be set by the volume (internal volume) of the sample quantitative measurer 8. The tip end of the passage 7f and the platinum electrode 18 are assumed to be moved together by the sample stage with respect to the respective samples placed thereon.
Even when the sample quantitative measurer 8 is not used, the amount of sample solution introduced can be easily controlled by adjusting the applied voltage and application time. More specifically, the amount can be controlled by suitably switching the passage change-over switches 14 and 15 so as to communicate with the passages 7f, 7d and 7g, and adjusting the magnitude and application time of the high voltage applied from the power supply for sample introduction 20 to the platinum electrodes 18 and 22.
Thereafter, the introduced sample solution is sent through the passage 7e to the constant-temperature reservoir 24, made to react within the reactor 23 of the reservoir 24 with the reactive reagent sent from the reactive reagent reservoir 11, and then sent to the quantitative measuring device 2. In this case, the constant-temperature reservoir 24 is kept at an optimum temperature for the reaction.
The quantitative measuring device 2 includes a passage change-over unit 25, the reacted sample quantitative measurer 26, the waste reactive solution reservoir 27 and the platinum electrode 28 and functions to perform a quantitative measuring operation over the reaction sample subjected to the reaction at the micro-reactor device 1 and then to supply the quantitative-measured sample to the analyzing device 3.
The analyzing device 3 as a capillary electro-phoresis device in the present embodiment includes a capillary tube 29, a buffer reservoir 30, a buffer waste solution reservoir 33, platinum electrodes 31 and 33, a power supply for analysis 32, an optical detector 35 and a recorder 36. In this case, used as the capillary tube was a glass capillary tube (manufactured by GL Sciences company) having an inner diameter of 75 μm and an outer diameter of 375 μm.
First of all, the power supply for analysis 32 is used to apply a high voltage between the platinum electrode 31 of the buffer reservoir 30 and the platinum electrode 34 of the buffer waste solution reservoir 33 to thereby provide preliminary electrophoresis to solution and to keep the solution in such an electrophoresis enable state. After that, the reacted sample within the reacted sample quantitative measurer 26 of the quantitative measuring device 2 is introduced into the capillary tube 29 for electrophoresis. Components of the reacted sample separated within the capillary tube 29 by the electrophoresis are detected by the optical detector 35, and the migration times and concentration values for the respective detected components are sent to the recorder 36 to be recorded therein.
Although the capillary electrophoresis device has been used as the analyzing device in the present embodiment, a high performance liquid chromatography device may be employed in place of the capillary electrophoresis device while not compelling great modification in the device arrangement.
Further, since such operations as mentioned above are controlled by the controller 4, when the applied voltage and time, the power change-over timing, the passage change-over timing, etc. are controlled in the form of a computer program, this control can be carried out with use of a single switch.
The detailed procedure of a change-over method between the solution and reactive reagent will be explained by referring to FIG. 4 showing a part of the micro-reactor device 1 in FIG. 1.
First of all, when it is desired to supply the solution, a power supply 61 for sample introduction is operated to apply a high voltage to a solution reservoir 63, in which case a power change-over switch 62, operatively connected with a passage change-over switch 65, is set at such a position as to form a thick solid line passage shown in FIG. 4A. Next, when it is desired to supply the reactive reagent, the power change-over switch 62 is switched to the other position so that, at the same time that a high voltage is applied to a reactive reagent reservoir 64, the passage change-over switch 65 operatively connected with the power change-over switch 62 is also switched, whereby such a path as shown by a thick solid line in FIG. 4B is established. In this case, passage change-over switches 66 and 67 are operatively connected with the power supply for sample introduction 61, so that, when it is desired to supply the solution by means of the power supply for sample introduction 61, such a path as shown by a thick solid line in FIG. 4B is formed.
The detailed procedures of a sample introducing method and a reaction method between the sample and reactive reagent will be explained by referring to FIG. 5 showing a part of the micro-device 1 in FIG. 1.
When it is desired to introduce the sample as shown in FIG. 5A, an automatic sample injector 73 is operated to insert a tip end of a passage 72a into a sample reservoir 75 placed on a sample stage 74, and then a power supply 77 for sample introduction is operated to apply a high voltage to between the sample and waste solution reservoirs 75 and 76. Application of the high voltage to the sample and waste solution reservoirs 75 and 76 causes generation of an electroosmotic flow, whereby the sample solution within the sample reservoir 75 flows through passages 72a, 71 and 72b sequentially in this order. At this time, the reactive reagent is also being supplied through passages 78a, 78b and 78c sequentially in this order. In other words, as shown in FIG. 5B, there are reactive reagents 80 and 81 at upstream and downstream or front and rear ends of a sample 79, that is, the sample is put in a sandwiched relation between the reactive reagents 80 and 81. Thereafter, supply of the solution by the electroosmotic flow causes the sample and reagents to flow while reacting with one another as shown in FIG. 5C. Further, since the sample 83 is put in the sandwiched relation between the reactive reagents 82 and 84 to be efficiently mixed with the reactive reagents 82 and 84 at the front and rear ends of the sample 83 through diffusion, the efficient reaction can be realized. As already explained above, the passage change-over switches 66 and 67, when it is desired to supply the solution by means of the operation of the power supply for sample introduction 61, are set at such positions as to form the path shown by the thick solid line in FIG. 4B. However, when it is desired to introduce the sample, power change-over to the power supply for sample introduction 77 causes change-over of the passage change-over switches 66 and 67, with the result that such a path as shown by a thick solid line in FIG. 5A is formed.
Explanation will be made as to the more detailed procedure of a method for analyzing the reactive sample in connection with FIG. 6 showing a part of the quantitative measuring device 2 and analyzing device 3 in FIG. 1.
First, for the purpose of providing preliminary electrophoresis, a power supply for analysis 95 is operated apply a high voltage to between a buffer reservoir 94 and a buffer waste solution reservoir 96. At this time, as shown in FIG. 6A, the reacted sample supplied from the micro-reactor device 1 is filled within a reacted sample quantitative measurer 92 of a passage change-over switch 91. Thereafter, the passage change-over switch 91 is switched so that the reacted sample is introduced into a capillary tube 93 for electrophoresis as shown by a thick solid line in FIG. 6B. In this connection, the passage change-over switch 91 is operatively connected with an optical detector 97 and a recorder 98 so that change-over of the switch 91 causes simultaneous analysis and recording of the sample thereat.
Since the transfer of the sample and reactive reagent is based on electroosmotic flow in the present embodiment, the diffusion of the sample and reactive reagent is as small as several tenths of that in the case of laminar flow. Further, substantially no pressure drop can be caused by the solution transfer, and the reaction between a very small amount of sample and reactive reagent can be efficiently carried out within a capillary tube as small as 100 μm or less in inner diameter. Furthermore, since the micro-reactor device is connected via the measuring device to the capillary electrophoresis device, a very small amount of sample can be accurately introduced into the capillary electro-phoresis device, and on-line analysis including reaction of the very small amount of sample with the reagent and separation of sample composition can be performed without involving any dilution and loss of the sample.
In the foregoing embodiment, explanation has been made in connection with such a system that is an integral combination of the micro-reactor device, measuring device and capillary electrophoresis device. Thus, when the micro-reactor device alone is extracted from the system, one terminal for supplying power to provide electroosmotic flow is missing in the micro-reactor device, but as this problem can be solved by providing a reservoir corresponding to the waste solution reservoir 27 of the quantitative measuring device 2 to the micro-reactor device.
Explanation will be made as to a micro-reactor device in accordance with a second embodiment of the present invention by referring to FIG. 7 showing its block diagram.
The illustrated micro-reactor device of the second embodiment includes power supplies 101 and 102, a reactive reagent reservoir 103, waste solution reservoirs 104 and 105, sample reservoirs 106a to 106d, passages 107a to 107f, passage change-over switches 108, 109, 110, 111, 112, 113 and 114, a measurer 115, a light source 116, a detector 117, and a controller 118. The micro-reactor device except the power supplies is formed on a planar plate insulator such as a glass plate, a single crystal silicone substrate, etc.
In more detail, the power supply 102 having a high output voltage of 0-30 kV is used to apply a high voltage between an electrode of the reactive reagent reservoir 103 and an electrode of the waste solution reservoir 104. The power supply 101 is used to apply a high voltage between electrodes of the sample reservoirs 106a to 106d and an electrode of the waste solution reservoir 105.
When the high voltage is applied between the electrode of the reactive reagent reservoir 103 and the electrode of the waste solution reservoir 104, the electroosmotic flow generated by the high voltage application causes the reactive reagent within the reactive reagent reservoir 103 to flow through the passages 107a, 107b and 107c sequentially in this order. Similarly, when the high voltage is applied between the electrodes of the sample reservoirs 106a to 106d and the electrode of the waste solution reservoir 105, the electroosmotic flow generated by the high voltage application causes the sample solution within the sample reservoirs 106a to 106d to flow through the passages 107d, 107e, 107b and 107f sequentially in this order. In the illustrated example, the micro-reactor device is designed for selective application of 4 samples. The flows of the above reactive reagent and sample can be switchingly controlled by means of the passage change-over switches 108, 109, 110 and 111 based on a signal issued from the controller 118. In this connection, the flow rate can be easily set by adjusting the applied voltage or time of the power supplies 101 and 102 on the basis of a signal from the controller 118.
The reaction of the micro-reactor device of the present embodiment is carried out in the following sequence.
First of all, the reactive reagent is introduced into the passages 107a, 107b and 107c, at which time the passage change-over switches 110 and 111-114 are operated to close the path and to stop the flowing of the sample. Subsequently, a high voltage is applied to between the electrode of the reactive reagent reservoir 103 and the electrode of the waste solution reservoir 104 so that the electroosmotic flow generated by the high voltage application causes the reactive reagent within the reactive reagent reservoir 103 to flow through the passages 107a, 107b and 107c sequentially in this order.
Thereafter, the passage change-over switches 108 and 109 are operated to close the path and to stop the flowing of the reactive reagent.
Next, when it is desired to introduce the sample into the passage 107b also functioning as a sample quantitative measurer, the power supply 101 for sample injection is operated to apply a high voltage between the electrode of the sample reservoir 106a and the electrode of the waste solution reservoir 105.
The passage change-over switches 110 and 111 are first operated to open the path. After that, a high voltage is applied to between the electrode of the sample reservoir 106a and the electrode of the waste solution reservoir 105 so that the electroosmotic flow generated by the high voltage application causes the sample within the sample reservoir 106a to flow through the passages 107d, 107e, 107b and 107f sequentially in this order. In this conjunction, the amount of sample introduced can be set by the capacity of the passage 107b functioning also as a sample quantitative measurer. Even with respect to the sample solutions of the sample reservoirs 106b to 106d, the sample introduction can be similarly controlled by the passage change-over switches 112, 113 and 114.
With respect to the introduced sample and reactive reagent, the passage change-over switches 110 and 111 are operated to close the path and to stop the flowing of the sample and subsequently the passage change-over switches 108 and 109 are operated to open the reactive reagent path. Under this condition, when the high voltage is applied between the electrode of the reactive reagent reservoir 103 and the electrode of the waste solution reservoir 104, the electroosmotic flow generated by the high voltage application causes the sample and reactive reagent to flow through the passages 107b and 107c while reacting with each other. Thus, there are reactive reagents at the front and rear ends of the sample introduced into the passage 107b, that is, the sample is put in a relationship sandwiched between the reactive reagents. Thereafter, the solution transfer based on the electroosmotic flow causes the sample and reactive reagent to react with each other while flowing. At this time, since the sample is sandwiched between the reactive reagents, the sample can be efficiently mixed with the reactive reagents at the front and rear ends thereof through diffusion for efficient reaction there-between. When the optimum temperature of the reaction is high, temperatures in the passages 107b and 107c can be set at proper levels for reaction without any troubles.
After that, light from the light source 116 is directed to the reacted sample. Change of light intensity due to the reacted sample is detected by the detector 117 to measure a sample quantity. In this connection, the change of light intensity means absorbance, fluorescence intensity, etc. Thus, the measurer 115 has a high light transmittance, and especially in case of absorbance change measurement, the measurer passage is provided thereon with a light reflecting layer to prolong its light path length. Further, when it is desired to measure a multiplicity of samples, this can be easily realized by sequentially operating the passage change-over switches 111, 112, 113 and 114 in similar procedures to the above.
The aforementioned operations are controlled by the controller 118, and thus when the applied voltage and time, passage change-over timing, etc. are controlled in accordance with a computer program, the operation control can be realized with use of a single switch.
More detailed explanation will be made as to the passage arrangement of the aforementioned micro-reactor device by referring to FIG. 8.
FIG. 8A shows a passage arrangement of the micro-reactor device. The passages of the micro-reactor device are formed by first providing very narrow grooves and small through holes in such a planar substrate as a glass or silicon substrate, overlapping another planar substrate on the former substrate, and then joining the substrates together by fusion bonding. As a result, passages 141a to 141h are defined by the very narrow grooves, while a reactive reagent reservoir 142, waste solution reservoirs 143 and 144, and sample reservoirs 145a to 145d are defined by the small through holes. The formation of the very small grooves and small through holes may be effected by mechanical machining with use of a drill or by chemical treatment such as etching. Further, passage change-over switches 146a to 146g may function to perform their switching operation by mechanically opening or closing the small through holes for passage change-over or by partially freezing or unfreezing the passages 141a to 141h.
FIG. 8B shows a side cross-sectional view of the micro-reactor device of FIG. 8A as viewed from a passage position A--A shown by arrows. In the drawing, reference numeral 200 denotes a planar substrate which is provided in its one surface with very small grooves and small through holes. Numeral 300 denotes a planar substrate overlapped on the substrate 200. The passage change-over switches 146a and 146c are provided therein with members 146a' and 146c' which function as stop plugs and, as already explained above, which are controlled by the controller 118 to open or close the associated passages. Further, the reactive reagent reservoir 142, waste solution reservoirs 143 and 144, and sample reservoirs 145a to 145d are provided on their walls with electrodes for providing electroosmotic flow (only two of which electrodes, for the reactive reagent reservoir 142 and the waste solution reservoir 144, being illustrated in the drawing).
Since the reactive reagent reservoir 142, waste solution reservoirs 143 and 144, and sample reservoirs 145a to 145d are provided in the same planar substrate in the present embodiment, the need for connecting the reactive reagent reservoir, waste solution reservoirs and sample reservoirs through connectors as in the prior art can be eliminated, and thus a leakage problem and the need for interconnections in very small areas can be removed. Further, since only the controller, high voltage power supplies and optical detector are provided as external devices, the entire apparatus can be made easily small in size.
Furthermore, since the reactive reagent reservoir 142, waste solution reservoirs 143 and 144, and sample reservoirs 145a to 145d are disposed as externally faced, introduction and the exchange of the reactive reagent and sample, washing, and waste solution removing can be facilitated. In this connection, the amounts of reactive reagent and sample used depend on the sizes of the reactive reagent reservoir and sample reservoirs. For this reason, minute amount of sample, as small as the microliter level, can be exchanged without any loss by making the diameter of the small through holes for the reactive reagent reservoir and sample reservoirs to be below 5000 μm. A measurer 147 includes a light transmittable part 148, made of silica glass having a high light transmittance, and a light reflecting layer 149. The light reflecting layer 149 is made preferably of material having an excellent reflectance such as platinum or rhodium. When it is desirable to provide the measurer in the form of a light transmission type, the reflecting layer 149 can be omitted.
Explanation will be made as to an example of the structure of a passage change-over means by referring to FIG. 9.
FIG. 9A shows a part of the passage change-over means which includes sample passages 151a and 15lb, reactive reagent passages 152a to 152c and passage change-over switches 153 and 154. In this case, the passage 152b functions also as a sample quantitative measurer. The sample quantitative measurement and reaction can be carried out by closing the passage change-over switches 153 and 154 to introduce the sample into the passage 152b functioning also as the sample quantitative measurer. FIG. 9B shows a side cross-sectional view of a part of a passage change-over means which includes Peltier elements 158, 159, 160 and 161 which are made in planar substrates 156 and 157, as opposed to each other with a passage 155 disposed therebetween. Passage change-over can be effected by cooling the solution in the passage to -15° C. or less by means of the Peltier elements 158, 159, 160 and 161 to close the passage 155.
According to the present embodiment, the passage change-over in microscopic areas can be facilitated with a simple arrangement because the opening and closing of the passages is carried out by freezing and unfreezing the solution in the passages. | A minute sample analysis system includes a micro-reactor device, a quantitative measuring device, an analyzing device and a controller, whereby, when a very small amount of sample is handled, its dilution and loss can be suppressed to minimum level, and analyzing operations ranging from reaction with a reactive reagent to separation/detection of the sample can be consistently carried out efficiently. The micro-reactor device controls the solution, reactive reagent and sample flowing in the form of electroosmotic flow generated by high-voltage application under control of passage change-over switches. The quantitative measuring device measures the quantity of reactive sample received from the micro-reactor device and introduces the measured reactive sample into the analyzing device. The analyzing device optically detects components separated from the sample through electrophoresis. The above operations are generally controlled under by the controller. | 6 |
BACKGROUND
Erythropoietin (EPO) is a 30.4 kilodalton (kDa) glycoprotein hormone that promotes the proliferation of erythroid progenitor cells and supports their differentiation into mature erythrocytes (see, for example, Krantz, Blood , 77:419-434, 1991). EPO is produced in the adult kidney and the fetal liver. In adults, EPO is produced primarily in kidney cells in response to hypoxia or anemia and circulates in the bloodstream. EPO targets the 66 kDa specific receptor (EPO-Rc) found almost exclusively on the surface of erythroid progenitor cells present in bone marrow. Upon binding EPO, the receptor is activated and undergoes homodimerization, followed by tyrosine phosphorylation. Subsequently, a series of intracellular signal transduction events take place, leading to the increase of the number of the progenitor cells and their maturation into erythrocytes (see, for example, Lodish et al., Cold Spring Harbor Symp. Quant. Biol ., 60:93-104, 1995).
Recombinant human EPO (rHuEPO) is widely used in the treatment of patients with chronic anemia due to renal diseases at both end-stage and pre-dialysis phases. Administration of EPO has also been successful to treat anemia in patients caused by cancer chemotherapy, rheumatoid arthritis, AZT treatment for HIV infection and myelodysplastic syndrome. No direct toxic effect of treatment has been reported and the benefits of blood transfusion could be achieved without the transfusion.
The concentration of EPO in normal human serum varies approximately from 0.01 to 0.03 units/ml. Supplemental EPO is a desirable treatment in cases of renal failure with decreased EPO production. The half-life for the serum clearance of intravenous (i.v.) rHuEPO is approximately 4 to 13 h. The peak serum concentration for subcutaneous (s.c.) rHuEPO occurs in 5 to 24 h after injection with an elimination half-life of 17 h. The s.c. administration route can therefore lead to much longer retention in the blood than i.v. administration of the same dose. The mechanism responsible for clearing EPO from the serum remains unclear. In animal experiments, less than 5% is excreted by the kidney. The liver, which rapidly removes asialated EPO, has not been shown to play a significant role in clearing EPO (see, for example, Fried, Annu. Rev. Nutr ., 15:353-377, 1995).
Immunoglobulins of IgG class are among the most abundant proteins in human blood. Their circulation half-lives can reach as long as 21 days. Fusion proteins have been reported to combine the Fc regions of IgG with the domains of another protein, such as various cytokines and soluble receptors (see, for example, Capon et al., Nature , 337:525-531, 1989; Chamow et al., Trends Biotechnol ., 14:52-60, 1996); U.S. Pat. Nos. 5,116,964 and 5,541,087). The prototype fusion protein is a homodimeric protein linked through cysteine residues in the hinge region of IgG Fc, resulting in a molecule similar to an IgG molecule without the CH1 domains and light chains. Due to the structural homology, Fc fusion proteins exhibit in vivo pharmacokinetic profile comparable to that of human IgG with a similar isotype. This approach has been applied to several therapeutically important cytokines, such as IL-2 and IFN-α 2a , and soluble receptors, such as TNF-Rc and IL-5-Rc (see, for example, U.S. Pat. Nos. 5,349,053 and 6,224,867). To extend the circulating half-life of EPO and/or to increase its biological activity, it is desirable to make fusion proteins containing EPO linked to the Fc portion of the human IgG protein as disclosed or described in this invention.
In most of the reported Fc fusion protein molecules, a hinge region serves as a spacer between the Fc region and the cytokine or soluble receptor at the amino-terminus, allowing these two parts of the molecule to function separately (see, for example, Ashkenazi et al., Current Opinion in Immunology , 9:195-200, 1997). Relative to the EPO monomer, a fusion protein consisting of two complete EPO domains separated by a 3- to 7-amino acid peptide linker exhibited reduced activity (Qiu et al., J. Biol. Chem ., 273:11173-11176, 1998). However, when the peptide linker between the two EPO domains was 17 amino acids in length, the dimeric EPO molecule exhibited considerably enhanced in vitro and in vivo activities. The enhanced activity has been shown to be due to an increased in vitro activity coupled with a different pharmacokinetic profile in mice (see, for example, Sytkowski et al., J. Biol. Chem ., 274:24773-24778, 1999; U.S. Pat. No. 6,187,564). A human EPO fusion protein with an appropriate peptide linker between the HuEPO and Fc moieties (HuEPO-L-Fc) is more active than rHuEPO, with in vitro activity at least 2-fold as that of rHuEPO on a molar basis. It is discovered according to this invention that an added peptide linker present between HuEPO and a human IgG Fc variant enhances the in vitro biological activity of the HuEPO-L-Fc molecule in two ways: (1) keeping the Fc region away from the EPO-Rc binding sites on EPO, and (2) keeping one EPO from the other EPO domain, so both EPO domains can interact with EPO-Rc on the erythroid progenitor cells independently. For the present invention, a flexible peptide linker of about 20 or fewer amino acids in length is preferred. It is preferably to use a peptide linker comprising of two or more of the following amino acids: glycine, serine, alanine, and threonine.
The Fc region of human immunoglobulins plays a significant role in immune defense for the elimination of pathogens. Effector functions of IgG are mediated by the Fc region through two major mechanisms: (1) binding to the cell surface Fc receptors (Fc γ Rs) can lead to ingestion of pathogens by phagocytosis or lysis by killer cells via the antibody-dependent cellular cytotoxicity (ADCC) pathway, or (2) binding to the C1q part of the first complement component C1 initiates the complement-dependent cytotoxicity (CDC) pathway, resulting in the lysis of pathogens. Among the four human IgG isotypes, IgG1 and IgG3 are effective in binding to Fc γ R. The binding affinity of IgG4 to Fc γ R is an order of magnitude lower than that of IgG1 or IgG3, while binding of IgG2 to Fc γ R is below detection. Human IgG1 and IgG3 are also effective in binding to C1q and activating the complement cascade. Human IgG2 fixes complement poorly, and IgG4 appears quite deficient in the ability to activate the complement cascade (see, for example, Jefferis et al., Immunol. Rev ., 163:59-76, 1998). For therapeutic use in humans, it is essential that when HuEPO-L-Fc binds to EPO-Rc on the surface of the erythroid progenitor cells, the Fc region of the fusion protein will not mediate undesirable effector functions, leading to the lysis or removal of these progenitor cells. Accordingly, the Fc region of HuEPO-L-Fc must be of a non-lytic nature, i.e. the Fc region must be inert in terms of binding to Fc γ Rs and C1q for the triggering of effector functions. It is clear that none of the naturally occurring IgG isotypes is suitable for use to produce the HuEPO-L-Fc fusion protein. To obtain a non-lytic Fc, certain amino acids of the natural Fc region have to be mutated for the attenuation of the effector functions.
By comparing amino acid sequences of human and murine IgG isotypes, a portion of Fc near the N-terminal end of the CH2 domain is implicated to play a role in the binding of IgG Fc to Fc γ Rs. The importance of a motif at positions 234 to 237 has been demonstrated using genetically engineered antibodies (see, for example, Duncan et al., Nature , 332:563-564, 1988). The numbering of the amino acid residues is according to the EU index as described in Kabat et al. (in Sequences of Proteins of Immunological Interest , 5 th Edition, United States Department of Health and Human Services, 1991). Among the four human IgG isotypes, IgG1 and IgG3 bind Fc γ Rs the best and share the sequence Leu234-Leu-Gly-Gly237 (only IgG1 is shown in FIG. 1 ). In IgG4, which binds Fc γ Rs with a lower affinity, this sequence contains a single amino acid substitution, Phe for Leu at position 234. In IgG2, which does not bind Fc γ Rs, there are two substitutions and a deletion leading to Val234-Ala-Gly237 ( FIG. 1 ). To minimize the binding of Fc to Fc γ R and hence the ADCC activity, Leu235 in IgG4 has been replaced by Ala (see, for example, Hutchins et al., Proc. Natl. Acad. Sci. USA , 92:11980-11984, 1995). IgG1 has been altered in this motif by replacing Glu233-Leu-Leu235 with Pro233-Val-Ala235, which is the sequence from IgG2. This substitution resulted in an IgG1 variant devoid of Fc γ R-mediated ability to deplete target cells in mice (see, for example, Isaacs et al., J. Immunol., 161:3862-3869, 1998).
A second portion that appears to be important for both Fc γ R and C1q binding is located near the carboxyl-terminal end of CH2 domain of human IgG (see, for example, Duncan et al., Nature , 332:738-740, 1988). Among the four human IgG isotypes, there is only one site within this portion that shows substitutions: Ser330 and Ser331 in IgG4 replacing Ala330 and Pro331 present in IgG1, IgG2, and IgG3 ( FIG. 1 ). The presence of Ser330 does not affect the binding to Fc γ R or C1q. The replacement of Pro331 in IgG1 by Ser virtually abolished IgG1 ability to C1q binding, while the replacement of Ser331 by Pro partially restored the complement fixation activity of IgG4 (see, for example, Tao et al., J. Exp. Med ., 178:661-667, 1993; Xu et al., J. Biol. Chem ., 269:3469-3474, 1994).
We discover that at least three Fc variants (vFc) can be designed for the production of HuEPO-L-vFc fusion proteins ( FIG. 1 ). Human IgG2 Fc does not bind Fc γ R but showed weak complement activity. An Fc γ2 variant with Pro331Ser mutation should have less complement activity than natural Fc γ2 while remain as a non-binder to Fc γ R. IgG4 Fc is deficient in activating the complement cascade, and its binding affinity to Fc γ R is about an order of magnitude lower than that of the most active isotype, IgG1. An Fc γ4 variant with Leu235Ala mutation should exhibit minimal effector functions as compared to the natural Fc γ4 . The Fc γ1 variant with Leu234Val, Leu235Ala and Pro331Ser mutations also will exhibit much less effector functions than the natural Fc γ1 . These Fc variants are more suitable for the preparation of the EPO fusion proteins than naturally occurring human IgG Fc. It is possible that other replacements can be introduced for the preparation of a non-lytic Fc without compromising the circulating half-life or causing any undesirable conformational changes.
There are many advantages with the present invention. The increased activity and prolonged presence of the HuEPO-L-vFc fusion protein in the serum can lead to lower dosages as well as less frequent injections. Less fluctuations of the drug in serum concentrations also means improved safety and tolerability. Less frequent injections may result in better patient compliance and quality of life. The HuEPO-L-vFc fusion protein containing a non-lytic Fc variant will therefore contribute significantly to the management of anemia caused by conditions including renal failure, cancer chemotherapy, rheumatoid arthritis, AZT treatment for HIV infection, and myelodysplastic syndrome.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a HuEPO-L-vFc fusion protein. The HuEPO-L-vFc fusion protein comprises HuEPO, a peptide linker, and a human IgG Fc variant. It is preferably to use a flexible peptide linker of 20 or fewer amino acids in length which comprises of two or more of the following amino acids: glycine, serine, alanine, and threonine. The IgG Fc variant is of non-lytic nature and contains amino acid mutations as compared to naturally occurring IgG Fc.
It is another embodiment of the present invention that the human Ig Fc comprises a hinge, CH2, and CH3 domains of human IgG, such as human IgG1, IgG2, and IgG4. The CH2 domain contains amino acid mutations at positions 228, 234, 235, and 331 (defined by the EU numbering system) to attenuate the effector functions of Fc.
In yet another embodiment of the present invention, a method is disclosed to make or produce such fusion proteins from a mammalian cell line such as a CHO-derived cell line. Growing transfected cell lines under conditions such that the recombinant fusion protein is expressed in its growth medium in excess of 10, preferably 30, μg per million cells in a 24 hour period. These HuEPO-L-vFc fusion proteins exhibit increased biological activity and extended serum half-life without undesirable side effects, leading to improved pharmacokinetics and pharmacodynamics, thus lower dosages and fewer injections would be needed to achieve similar efficacies.
BRIEF DESCRIPTIONS OF THE DRAWINGS
FIG. 1 shows the amino acid sequence alignment from the hinge and CH2 regions of human IgG1, IgG2, IgG4 and their variants. Three portions are compared: amino acid position 228, 234-237, and 330-331. Amino acid mutations of the variants are indicated in bold italics. The EU numbering system is used for the amino acid residues.
FIG. 2 shows the nucleotide sequence and deduced amino acid sequence of (A) HuEPO-L-vFc γ2 , (B) HuEPO-L-vFc γ4 , and (C) HuEPO-L-vFc γ1 as the HindIII-EcoRI fragment in the respective pEFP expression vector. The peptide from amino acid residues −27 to −1 is the leader peptide of human EPO. The mature protein contains human EPO (amino acid residues 1 to 165), a peptide linker (amino acid residues 166 to 181), and a Fc variant (amino acid residues 182 to 409 of vFc γ2 , 182 to 410 of vFc γ4 , and 182 to 408 of vFc γ1 ). In the Fc regions, nucleotide and corresponding amino acid mutations in bold are also underlined. FIG. 3 shows non-limiting examples of amino acid sequences (16, 15, 10, and 4 amino acids) in the flexible peptide linkers and an example.
DETAILED DESCRIPTION OF THE INVENTION
1. Construction of the Gene Encoding the HuEPO-L-vFc γ2 Fusion Protein
A fusion protein is assembled from several DNA segments. To obtain the gene encoding the leader peptide and mature protein of human EPO, cDNA library of human fetal liver or kidney (obtained from Invitrogen, Carlsbad, Calif.) is used as the template in polymerase chain reaction (PCR). For the convenience of cloning, SEQ ID NO:1 (Table 1), which incorporates a restriction enzyme cleavage site (HindIII) is used as the 5′ oligonucleotide primer. Table 1 shows the sequences of oligonucleotides used for the cloning of the HuEPO-L-vFc fusion proteins. The 3′ primer (SEQ ID NO:2) eliminates the EPO termination codon and incorporates a BamHI site. The resulting DNA fragments of approximately 600 bp in length are inserted into a holding vector such as pUC19 at the HindIII and BamHI sites to give the pEPO plasmid. The sequence of the human EPO gene is confirmed by DNA sequencing.
The gene encoding the Fc region of human IgG2 (Fc γ2 ) is obtained by reverse transcription and PCR using RNA prepared from human leukocytes and appropriate 5′ (SEQ ID NO:3) and 3′ (SEQ ID NO:4) primers. Resulting DNA fragments of Fc γ2 containing complete sequences of the hinge, CH2, and CH3 domains of IgG2 will be used as the template to generate the Fc γ2 Pro331Ser variant (vFc γ2 ) in which Pro at position 331 of Fc γ2 is replaced with Ser. To incorporate this mutation, two segments are produced and then assembled by using the natural Fc γ2 as the template in overlapping PCR. The 5′ segment is generated by using SEQ ID NO:3 as the 5′ primer and SEQ ID NO:5 as the 3′ primer. The 3′ segment is generated by using SEQ ID NO:6 as the 5′ primer and SEQ ID NO:4 as the 3′ primer. These two segments are then joined at the region covering the Pro331 Ser mutation by using SEQ ID NO:7 as the 5′ primer and SEQ ID NO:4 as the 3′ primer. The SEQ ID NO:7 primer contains sequences encoding a 16-amino acid Gly-Ser peptide linker including a BamHI restriction enzyme site. The resulting DNA fragments of approximately 700 bp in length are inserted into a holding vector such as pUC19 at the BamHI and EcoRI sites to give the pL-vFc γ2 plasmid. The sequence of the gene is confirmed by DNA sequencing.
To prepare the HuEPO-L-vFc γ2 fusion gene, the EPO fragment is excised from the pEPO plasmid with HindIII and BamHI and is purified by agarose gel electrophoresis. The purified fragment is then inserted to the 5′-end of the peptide linker in the pL-vFcγ2 plasmid to give the pEPO-L-vFcγ2 plasmid. The fusion gene comprises HuEPO, a Gly-Ser peptide linker and the Fc γ2 variant gene.
The presence of a peptide linker between the EPO and Fc moieties increases the flexibility of the EPO domains and enhances its biological activity (see, for example, Sytkowski et al., J. Biol. Chem ., 274:24773-8, 1999). For the present invention, a peptide linker of about 20 or fewer amino acids in length is preferred. Peptide linker comprising two or more of the following amino acids: glycine, serine, alanine, and threonine can be used. An example of the peptide linker contains Gly-Ser peptide building blocks, such as GlyGlyGlyGlySer (SEQ ID NO. 29). FIG. 2A shows a fusion gene (SEQ ID NO. 17) containing sequences encoding HuEPO, a 16-amino acid peptide linker (GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer, SEQ ID NO: 23), and the Fc γ2 Pro331Ser variant, and its corresponding amino acid sequence (SEQ ID NO. 18).
The complete gene encoding the HuEPO-L-vFc fusion protein is then inserted at the HindIII and EcoRI sites of a mammalian expression vector, such as pcDNA3 (Invitrogen). The final expression vector plasmid, named pEFP2, contains the cytomegalovirus early gene promoter-enhancer which is required for high level expression in mammalian cells. The plasmid also contains selectable markers to confer ampicillin resistance in bacteria, and G418 resistance in mammalian cells. In addition, the pEFP2 expression vector contains the dihydrofolate reductase (DHFR) gene to enable the co-amplification of the HuEPO-L-vFcγ2 fusion gene and the DHFR gene in the presence of methotrexate (MTX) when the host cells are deficient in the DHFR gene expression (see, for example, U.S. Pat. No. 4,399,216).
2. Construction of the Gene Encoding the HuEPO-L-vFc Fusion Protein
Human IgG4 is observed partly as half antibody molecules due to the dissociation of the inter-heavy chain disulfide bonds in the hinge domain. This is not seen in the other three human IgG isotypes. A single amino acid substitution replacing Ser228 with Pro, which is the residue found at this position in IgG1 and IgG2, leads to the formation of IgG4 complete antibody molecules (see, for example, Angal et al., Molec. Immunol ., 30:105-108, 1993; Owens et al., Immunotechnology , 3:107-116, 1997; U.S. Pat. No. 6,204,007). The Fc γ4 variant containing Leu235Ala mutation for the minimization of FcR binding will also give rise to a homogeneous fusion protein preparation with this additional Ser228Pro mutation.
The gene encoding the Fc region of human IgG4 (Fc γ4 ) is obtained by reverse transcription and PCR using RNA prepared from human leukocytes and appropriate 5′ primer (SEQ ID NO:8) and 3′ primer (SEQ ID NO:9). Resulting DNA fragments of Fc γ4 containing complete sequences of the hinge, CH2, and CH3 domains of IgG4 is used as the template to generate the Fc γ4 variant with Ser228Pro and Leu235Ala mutations (vFc γ4 ) in which Ser228 and Leu235 have been replaced with Pro and Ala, respectively. The CH2 and CH3 domains are amplified using the 3′ primer (SEQ ID NO:9) and a 5′ primer containing the Leu235Ala mutation (SEQ ID NO:10). This amplified fragment, together with a synthetic oligonucleotide of 60 bases in length (SEQ ID NO:11) containing both Ser228Pro and Leu235Ala mutations, are joined in PCR by using SEQ ID NO:12 as the 5′ primer and SEQ ID NO:9 as the 3′ primer. The SEQ ID NO:12 primer contains sequences encoding a 16-amino acid Gly-Ser peptide linker including the BamHI site. The resulting DNA fragments of approximately 700 bp in length are inserted into a holding vector such as pUC19 at the BamHI and EcoRI sites to give the pL-vFcγ4 plasmid. The sequence of the gene is confirmed by DNA sequencing.
To prepare the HuEPO-L-vFc γ4 fusion gene, the HuEPO fragment is excised from the pEPO plasmid with HindIII and BamHI and then inserted to the 5′-end of the peptide linker in the pL-vFcγ4 plasmid to give the pEPO-L-vFcγ4 plasmid. This fusion gene comprising HuEPO, a 16-amino acid Gly-Ser peptide linker and the Fc γ4 variant gene is then inserted at the HindIII and EcoRI sites of a mammalian expression vector, such as pcDNA3 (Invitrogen), as described for the HuEPO-L-vFc γ2 fusion protein. The final expression vector plasmid is designated as pEFP4. FIG. 2B shows a fusion gene (SEQ ID NO. 19) containing sequences encoding HuEPO, a 16-amino acid peptide linker (GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer, SEQ ID NO: 23), and the Fc γ4 variant with Ser228Pro and Leu235Ala mutations, and its corresponding amino acid sequence (SEQ ID NO. 20).
3. Construction of the Gene Encoding the HuEPO-L-vFc γ1 Fusion Protein
The hinge domain of human IgG1 heavy chain contains 15 amino acid residues (GluProLysSerCysAspLysThrHisThrCysProProCysPro), SEQ ID NO: 24 including 3 cysteine residues. Out of these 3 cysteine residues, the 2nd and 3rd are involved in the formation of disulfide bonding between two heavy chains. The 1st cysteine residue is involved in the disulfide bonding to the light chain of IgG. Since there is no light chain present in the Fc fusion protein molecule, this cysteine residue may pair with other cysteine residues, leading to nonspecific disulfide bonding. The hinge domain of Fc γ1 can be truncated to eliminate the 1st cysteine residue (AspLysThrHisThrCysProProCysPro), SEQ ID NO: 25. The gene encoding the Fc γ1 region is obtained by reverse transcription and PCR using RNA prepared from human leukocytes and appropriate 5′ primer (SEQ ID NO:13) and 3′ primer (SEQ ID NO:4). Resulting DNA fragments containing the truncated hinge and complete sequences of CH2 and CH3 domains of Fc γ1 is used as the template to generate the Fc γ1 variant with Leu234Val, Leu235Ala, and Pro331 Ser mutations (vFc γ1 ).
One way to incorporate these mutations is as follows: two segments are produced and then assembled by using the natural Fc γ1 as the template in overlapping PCR. The 5′ segment is generated by using SEQ ID NO:14 as the 5′ primer and SEQ ID NO:5 as the 3′ primer. This 5′ primer contains the Leu234Val, Leu235Ala mutations and the 3′ primer contains the Pro331Ser mutation. The 3′ segment is generated by using SEQ ID NO:6 as the 5′ primer and SEQ ID NO:4 as the 3′ primer. These 5′ and 3′ segments are then joined at the region covering the Pro331 Ser mutation by using SEQ ID NO:14 as the 5′ primer and SEQ ID NO:4 as the 3′ primer. This amplified fragment of approximately 650 bp in length, together with a synthetic oligonucleotide of 55 bases (SEQ ID NO:15) containing Leu234Val and Leu235Ala, are joined in PCR by using SEQ ID NO:16 as the 5′ primer and SEQ ID NO:4 as the 3′ primer. The SEQ ID NO:16 primer contains sequences encoding a 16-amino acid Gly-Ser peptide linker including the BamHI site. The resulting DNA fragments of approximately 700 bp in length are inserted into a holding vector such as pUC19 at the BamHI and EcoRI sites to give the pL-vFcγ1 plasmid. The sequence of the gene is confirmed by DNA sequencing.
To prepare the HuEPO-L-vFc γ1 fusion gene, the EPO fragment is excised from the pEPO plasmid with HindIII and BamHI and inserted to the 5′-end of the peptide linker in the pL-vFcγ1 plasmid to give the pEPO-L-vFcγ1 plasmid. The fusion gene comprising HuEPO, a 16-amino acid Gly-Ser peptide linker, and the Fc γ1 variant gene is then inserted at the HindIII and EcoRI sites of a mammalian expression vector, such as pcDNA3 (Invitrogen), as described for the HuEPO-L-vFc γ2 fusion protein. The final expression vector plasmid is designated as pEFP1. FIG. 2C shows a fusion gene (SEQ ID NO. 21) containing sequences encoding HuEPO, a 16-amino acid peptide linker (GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer, SEQ ID NO: 23), and the Fc γ1 variant with Leu234Val, Leu235Ala and Pro331Ser mutations, and its corresponding amino acid sequence (SEQ ID NO. 22).
4. Expression of the Fusion Protein in Transfected Cell Lines
The recombinant pEFP1, pEFP2 or pEFP4 expression vector plasmid is transfected into a mammalian host cell line to achieve the expression of the HuEPO-L-vFc fusion protein. For stable high levels of expression, a preferred host cell line is Chinese Hamster Ovary (CHO) cells deficient in the DHFR enzyme (see, for example, U.S. Pat. No. 4,818,679). A preferred method of transfection is electroporation. Other methods, including calcium phosphate co-precipitation, lipofectin, and protoplast fusion, can also be used. For electroporation, 10 μg of plasmid DNA linearized with BspCI is added to 2 to 5×10 7 cells in a cuvette using Gene Pulser Electroporator (Bio-Rad Laboratories, Hercules, Calif.) set at an electric field of 250 V and a capacitance of 960 μFd. Two days following the transfection, the media are replaced with growth media containing 0.8 mg/ml of G418. Transfectants resistant to the selection drug are tested for the secretion of the fusion protein by anti-human IgG Fc ELISA. Quantitation of the expressed fusion protein can also be carried out by ELISA using anti-HuEPO assays. The wells producing high levels of the Fc fusion protein are subcloned by limiting dilutions on 96-well tissue culture plates.
To achieve higher levels of the fusion protein expression, co-amplification is preferred by utilizing the gene of DHFR which can be inhibited by the MTX drug. In growth media containing increasing concentrations of MTX, the transfected fusion protein gene is co-amplified with the DHFR gene. Transfectants capable of growing in media with up to 1 μg/ml of MTX are again subcloned by limiting dilutions. The subcloned cell lines are further analyzed by measuring the secretion rates. Several cell lines yielding secretion rate levels over about 10, preferably about 30 μg/10 6 cells/24 h, are adapted to suspension culture using serum-free growth media. The conditioned media are then used for the purification of the fusion protein.
Sugar side chain structures are crucial for the in vivo activity of EPO. The terminal sugar chain of the Asn-linked carbohydrate contains sialic acids, repeating poly-N-acetyllactosamine and galactose. Recombinant HuEPO expressed in certain mammalian cells such as NS0 is known to give proteins with low sialic acid content. Removal of sialic acids, which leads to exposure of the penultimate galactose residues, increases the affinity for hepatic asialoglycoprotein binding lectin. This trapping pathway results in decrease of in vivo biological activity as measured in whole animals. Recombinant HuEPO produced in CHO cells exhibit glycosylation patterns very similar to that found in the natural EPO (see, for example, Takeuchi et al., Proc. Natl. Acad. Sci. USA , 86:7819-22, 1989). The HuEPO-L-vFc fusion proteins expressed and produced in accordance with this invention will show enhanced biological activities when compared to rHuEPO on a molar basis.
5. Purification and Characterization of the Fusion Protein
Conditioned media containing the fusion protein are titrated with 1 N NaOH to a pH of 7 to 8 and filtered through a 0.45 micron cellulose nitrate filter. The filtrate is loaded onto a Prosep A column equilibrated in phospate-buffered saline (PBS). After binding of the fusion protein to Prosep A, the flow-through fractions are discarded. The column is washed with PBS until OD at 280 nm is below 0.01. The bound fusion protein is then eluted with 0.1 M citrate buffer at pH 3.75. After neutralizing with 0.4 volume of 1 M K 2 HPO 4 , fractions containing purified protein are pooled and dialyzed against PBS. The solution is then filtered through a 0.22 micron cellulose nitrate filter and stored at 4° C. The molecular weight of purified HuEPO-L-vFc protein is in the range of 110 and 130 kDa by SDS-PAGE under non-reducing conditions. Under reducing conditions, the purified protein migrates around approximately 60 kDa. The fusion protein is quantitated by BCA protein assay using BSA as the standard.
6. In Vitro Biological Assays
Supernatants of transfectants or purified proteins can be tested for their ability to stimulate the proliferation of TF-1 cells (Kitamura et al., J. Cell. Physiol ., 140:323-334, 1989). TF-1 cells naturally express human EPO-Rc on their cell surface and are responsive to EPO. The cells are maintained in growth medium (RPMI-1640 medium containing 10% FCS and human IL-5 at 1 to 5 ng/ml). Log phase TF-1 cells are collected and washed with assay medium (growth medium without human IL-5). A total of 1×10 4 cells per sample of TF-1 in 50 μl is added to each well of a 96-well tissue culture plate. The cells are incubated with 50 μl of assay media containing various concentrations of the HuEPO-L-vFc fusion protein or the rHuEPO control from 0.01 to 100 nM each. The plate is kept at 37° C. and 5% CO 2 in a humidified incubator for 4 days before 10 μl of MTT (2.5 mg/ml in PBS) is added to each well. After 4 h, the cells and formazan are solubilized by adding 100 μl per well of 10% SDS in 0.01 N HCl. The plate is then read at 550 nm with the reference beam set at 690 nm. The OD reading is plotted against the concentration of rHuEPO or the fusion protein. The inflection point of the sigmoidal curve represents the concentration at which 50% of the maximal effect, ED50, is induced. The biological activity of HuEPO-L-vFc relative to that of rHuEPO can therefore be compared quantitatively. Preferably, the fusion proteins should exhibit an enhanced activity of at least 2 fold relative to that of rHuEPO on a molar basis. In one embodiment of the present invention, the specific activity of the HuEPO-L-vFc fusion protein is in the range of about 6 to about 8×10 6 units/μmole, compared to about 3 to about 4×10 6 units/μmole for rHuEPO.
Supernatants of transfectants or purified proteins can also be tested for their ability to stimulate the proliferation and differentiation of human bone marrow progenitor cells to form red blood cell colonies, colony forming unit-erythroid (CFU-E). The procedure is as follows. Light-density cells from human bone marrow centrifuged over Ficoll-Pague are washed and resuspended at 1×10 6 cells/ml in Iscove's modified Dulbecco's medium (IMDM) containing 5% FCS. These cells are incubated in a tissue culture dish overnight at 37° C. and 5% CO 2 to remove all adherent cells including monocytes, macrophages, endothelial cell, and fibroblasts. Cells in suspension are then adjusted to 1×10 5 cells/ml in IMDM containing 5% FCS. For the assay, 0.3 ml of cells, 15 μl of stem cell factor at 20 μg/ml, 2.4 ml of methylcellulose, and 0.3 ml of media containing several concentrations of HuEPO-L-vFc (or rHuEPO control) are mixed. One ml of this cell mixture is plated on a 35-mm petri dish. The dishes are then kept at 37° C. and 5% CO 2 for 10 to 14 d before the colonies are counted. A dose responsive curve can be plotted against the concentrations of HuEPO-L-vFc relative to those of rHuEPO.
7. In Vivo Pharmacokinetic Studies in Rats
Fisher rats (Harlan Bioproducts for Science, Indianapolis, Ind.) with an average body weight of about 500 g are injected i.v. through the tail vein or s.c. with 100 units of rHuEPO or the HuEPO-L-vFc fusion protein. An equal volume of PBS is injected as a control. Serial 0.5-ml samples are taken through retro-orbital bleeds at different points (0, 0.2, 1, 4, 24, 48, 96, and 168 h) after injection. There are 3 rats for each time point. Whole blood is collected into tubes containing anticoagulant, cells are removed, and plasma is frozen at −70° C. until assay is carried out.
Serum samples are used for TF-1 cell assays, which measure the activity of EPO-mediated cell proliferation. A total of 1×10 4 cells per sample of TF-1 in 50 μl is added to each well of a 96-well tissue culture plate. The cells are incubated with 50 μl of assay media containing various concentrations of titrated blood samples. The plate is kept at 37° C. and 5% CO 2 in a humidified incubator for 4 days. Viable cells are stained with 10 μl of MTT (2.5 mg/ml in PBS). After 4 h, the cells and formazan are solubilized by adding 100 μl per well of 10% SDS in 0.01 N HCl. The plate is then read at 550 nm with the reference beam set at 690 nm. The activities of serum samples are plotted against time points for the calculation of the circulation time. The activity of HuEPO-L-vFc decreases much slower than that of the rHuEPO control, indicating the longer circulating half-life of the fusion protein in rats.
The examples described above are for illustration purposes only. They are not intended and should not be interpreted to limit either the scope or the spirit of this invention. It can be appreciated by those skilled in the art that many other variations or substitutes can be used as equivalents for the purposes of this invention, which is defined solely by the written description and the following claims.
TABLE 1
Sequences of Oligonucleotides.
5′-cccaagcttggcgcggagatgggggtgca-3′
SEQ ID NO:1
5′-cggatccgtcccctgtcctgcaggcct-3′
SEQ ID NO:2
5′-gagcgcaaatgttgtgtcga-3′
SEQ ID NO:3
5′-ggaattctcatttacccggagacaggga-3′
SEQ ID NO:4
5′-tggttttctcgatggaggctgggaggcct-3′
SEQ ID NO:5
5′-aggcctcccagcctccatcgagaaaacca-3′
SEQ ID NO:6
5′-cggatccggtggcggttccggtggaggcggaagcggcggtggaggatcag
SEQ ID NO:7
agcgcaaatgttgtgtcga-3′
5′-gagtccaaatatggtccccca-3′
SEQ ID NO:8
5′-ggaattctcatttacccagagacaggga-3′
SEQ ID NO:9
5′-cctgagttcgcggggggacca-3′
SEQ ID NO:10
5′-gagtccaaatatggtcccccatgcccaccatgcccagcacctgagttcgcgg
SEQ ID NO:11
ggggacca-3′
5′-cggatccggtggcggttccggtggaggcggaagcggcggtggaggatcagag
SEQ ID NO:12
tccaaatatggtccccca-3′
5′-gacaaaactcacacatgccca-3′
SEQ ID NO:13
5′-acctgaagtcgcggggggaccgt-3′
SEQ ID NO:14
5′-gacaaaactcacacatgcccaccgtgcccagcacctgaagtcgcggggggac
SEQ ID NO:15
cgt-3′
5′-cggatccggtggcggttccggtggaggcggaagcggcggtggaggatcagac
SEQ ID NO:16
aaaactcacacatgccca-3′ | Fc fusion proteins of human EPO with increased biological activities relative to rHuEPO on a molar basis are disclosed. The HuEPO-L-vFc fusion protein comprises HuEPO, a flexible peptide linker of about 20 or fewer amino acids, and a human IgG Fc variant. The Fc variant is of a non-lytic nature and shows minimal undesirable Fc-mediated side effects. A method is also disclosed to make or produce such fusion proteins at high expression levels. Such HuEPO-L-vFc fusion proteins exhibit extended serum half-life and increased biological activities, leading to improved pharmacokinetics and pharmacodynamics, thus fewer injections will be needed within a period of time. | 2 |
[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 61/639,949 filed Apr. 29, 2012.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates generally to cementing equipment used with oilfield wellhead equipment and, in particular aspects, to couplings that are useful for such equipment.
[0004] 2. Description of the Related Art
[0005] After a hydrocarbon wellbore has been drilled, a casing is typically cemented in along the length of the drilled bore. Cementing equipment is used to do this and typically includes a top drive cement head that permits balls or rubber darts to be dropped into the wellbore during the cementing operation. The cement head also must be capable of flowing cement from a cement supply downwardly into the wellbore. Suitable cementing equipment for these purposes includes a top drive cement head which is available commercially from Baker Hughes Incorporated of Houston, Tex.
SUMMARY OF THE INVENTION
[0006] The invention provides methods and devices for quickly connecting and disconnecting a conduit to a port. In a described embodiment, a quick connect coupling is described for quickly connecting and disconnecting a cement supply conduit to the port of a top drive cement swivel. An exemplary quick connect coupling includes a stinger assembly that is reversibly coupled to a breech lock box connector on the cement swivel. Raised keys on the breech lock barrel will interfit with complimentary ridges with a bore of the breech lock connector.
[0007] In certain embodiments, a locking arrangement that secures the stinger assembly against rotation within the breech lock connector. In one embodiment, a locking pin is used to lock the stinger assembly into place and against rotation with respect to the cement swivel. An exemplary locking pin is described that is retained by the cement swivel and is axially moveable between unlocked and locked positions. In the locked position, the locking pin will reside within a complimentary indentation within the stinger assembly thereby preventing rotation.
[0008] In operation, a user can quickly and easily couple the stinger assembly with the cement swivel easily and without the need for hammers and other tools to be used. A crane may be used to lift and move the stinger assembly and affixed cement conduit to a position that is proximate the breech lock box connector of the cement swivel. An operator can then orient the stinger assembly so that the keys of the stinger assembly are angularly offset from the ridges within the bore. The stinger and breech lock barrel are then inserted into the bore. Thereafter, the user rotates the stinger assembly to align the keys of the stinger assembly with the ridges of the bore. When aligned, each of the keys are preferably located in line with and behind a ridge, preventing the stinger assembly from being withdrawn from the breech lock connector. The locking arrangement is then engaged to lock the stinger assembly in place so that it cannot be rotated with the breech lock connector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein:
[0010] FIG. 1 is a side view of portions of an exemplary wellbore cementing operation.
[0011] FIG. 2 is an isometric view of an exemplary stinger assembly in accordance with the present invention.
[0012] FIG. 3 is a side view of the stinger assembly shown in FIG. 2 .
[0013] FIG. 4 is a cross-sectional view taken along lines 4 - 4 in FIG. 3 .
[0014] FIG. 5 is a front view of an exemplary cement swivel with stinger assembly attached in accordance with the present invention.
[0015] FIG. 6 is a cross-sectional view taken along lines 6 - 6 in FIG. 5 .
[0016] FIG. 7 is a front view of the cement swivel and stinger assembly depicting the stinger assembly being coupled to the swivel.
[0017] FIG. 8 is an enlarged cross-sectional view of portions of an exemplary coupling in accordance with the present invention.
[0018] FIG. 9 is a side view of the exemplary cement swivel and stinger assembly shown in an unlocked condition.
[0019] FIG. 10 is a side view of the cement swivel and stinger assembly of FIG. 9 , now in a locked condition.
[0020] FIG. 11 is a cross-sectional view, partially in phantom, showing portions of the stinger assembly and cement swivel in an unsecured condition.
[0021] FIG. 12 is a cross-sectional view, partially in phantom, showing portions of the stinger assembly and cement swivel now in a secured condition.
[0022] FIG. 13 is an isometric view of an exemplary breech lock barrel shown apart from other components of the coupling.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] FIG. 1 illustrates portions an exemplary cementing operation for a wellbore. A tubular working string 10 extends downwardly into a wellhead 12 . A cementing tool 14 is incorporated into the working string 10 which typically contains balls and/or plugs which are launched into the working string 10 during a cementing operation. A top drive cement swivel 16 is affixed to the upper end of the cementing tool 14 . The cement swivel 16 operates to receive cement and transmit it through a flowpath in the cementing tool 14 so that the cement can be flowed downwardly into the working string 10 . FIG. 1 also depicts a cement hose 18 with an affixed stinger assembly 20 . Cement can be flowed to the cement swivel 16 when the stinger assembly 20 is coupled to the cement swivel 16 . The cement hose 18 and stinger assembly 20 are depicted being lifted by block and tackle 22 .
[0024] The structure and operation of an exemplary stinger assembly 20 are better appreciated with further reference to FIGS. 2-4 . The stinger assembly 20 includes a curved rigid pipe portion 24 that is affixed to the hose 18 . A flange 26 with lifting eye 28 extends upwardly from the pipe portion 24 . A stinger 30 extends outwardly from the pipe portion 24 . A cement flow path 32 is defined within the pipe portion 24 and stinger 30 . A breech lock barrel 34 radially surrounds the stinger 30 and, as can be seen best in FIGS. 4 and 8 , secured to the stinger 30 by a sleeve 36 that preferably permits the breech lock barrel 34 to rotate about the stinger 30 . FIG. 13 shows the breech lock barrel 34 apart from the other components of the stinger assembly 20 . A flange 38 projects radially outwardly from the breech lock barrel 34 and presents at least one indentation 40 . In the depicted embodiment, there are six indentations 40 . In preferred embodiments, an enlarged grippable handle 42 also radially surrounds the stinger 30 and is secured by bolts 44 ( FIG. 2 ) to the breech lock barrel 34 so that the stinger 30 will be rotated when the handle 42 is rotated.
[0025] The outer radial surface of the breech lock barrel 34 preferably presents a plurality of raised keys 46 . As will be appreciated with regard to FIGS. 2 , 3 , 4 and 8 , the keys 46 are organized into rows (A, B and C) and perpendicular columns. The keys 46 are spaced apart from each other along each of the rows A, B and C and each of the columns. In some embodiments, there are six keys 46 per row A, B and C spaced angularly from each other at about 30 degrees apart. In certain embodiments, the breech lock barrel 34 also includes a row of raised anti-rotation locking dogs 47 . In the depicted embodiment, there are six locking dogs 47 that are positioned in a spaced relation from one another of about 30 degrees apart.
[0026] The structure of the exemplary top drive cement swivel 16 is better understood with reference to FIGS. 5-10 . It can be seen that the cement swivel 16 has a generally box-shaped main housing 50 . A central axial flowbore 52 passes vertically through the main housing 50 . Lateral fluid flow openings 54 , 56 extend through the main housing 50 and permit fluid communication between the central flowbore 52 and the exterior of the cement swivel 16 . A tubular breech lock box connector 58 extends outwardly from the main housing 50 . As illustrated in FIGS. 11 and 12 , the breech lock box connector 58 defines an interior bore 60 having a plurality of inwardly projecting ridges 62 . The ridges 62 are spaced apart from each other both radially and axially within the bore 60 . Preferably, the interior bore 60 also includes an annular fluid seal 63 ( FIG. 8 ) that creates a fluid seal against the stinger 30 when it is inserted into the bore 60 . In addition, the interior bore 60 also presents a row of inwardly projecting anti-rotation locking dogs 48 . The dogs 48 are meant to be complimentary to the anti-rotation dogs 47 of the breech lock barrel 34 .
[0027] FIGS. 9 and 10 illustrate a locking pin 64 which is preferably used with the cement swivel 16 and is used to lock the stinger assembly 20 into a coupled position with respect to the cement swivel 16 . The locking pin 64 is preferably retained by a sleeve 66 and is axially shiftable between two positions. In the unlocked position shown in FIG. 9 , the locking pin 64 does not prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 . In the locked position shown in FIG. 10 , the locking pin 64 is disposed within an indentation 40 of the flange 38 and will prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 . In particular embodiments, the locking pin 64 has a handle portion 68 that can be used to rotate and shift the locking pin 64 between the unlocked and locked positions.
[0028] In operation, a user can rapidly couple or uncouple the cement conduit 18 to the cement swivel 16 . In order to couple the stinger assembly 20 to the cement swivel 16 , the block and tackle 22 is used to lift and move the stinger assembly 20 by lifting eye 28 until the stinger assembly 20 is proximate the breech lock connector 58 of the cement swivel 16 . A user can then grasp the handle 42 of the stinger assembly 20 and rotate the stinger assembly 20 to the approximate position shown in FIG. 7 . In FIG. 7 , the stinger assembly 20 is rotated approximately 30 degrees from the vertical, as illustrated in FIG. 7 . This rotation will align the keys 46 of the stinger assembly 20 angularly between the ridges 62 of the breech lock barrel bore 60 so that the breech lock barrel 34 can be fully inserted into the bore 60 , as illustrated in FIG. 11 . Once fully inserted, the user will rotate the stinger assembly 20 approximately 30 degrees back to the position depicted in FIG. 5 . This rotation will move the raised keys 46 of the breech lock barrel 34 to the position illustrated in FIG. 12 , wherein each key 46 is located behind a ridge 62 within the bore 60 . Also, each row A, B and C of keys 46 is located behind a row of ridges 62 . The locking dogs 47 will radially abut the dogs 48 of the bore 60 (as depicted in FIG. 12 ), preventing further rotation beyond 30 degrees. In this position, the stinger assembly 20 cannot be axially withdrawn from the bore 60 . The stinger assembly 20 is now coupled to the cement swivel 16 . The user can now move the locking pin 64 from the unlocked position ( FIG. 9 ) to the locked position ( FIG. 10 ) as described previously. Seating of the locking pin 64 within the indentation 40 will prevent the stinger assembly 20 from being inadvertently rotated and uncoupled from the cement swivel 16 . Cement can now be flowed along the cement flow path 32 from the cement conduit 18 into the lateral flow opening 54 of the cement swivel and into the central flowbore 52 of the cement swivel 16 .
[0029] In order to uncouple the stinger assembly 20 from the cement swivel 16 , a user will reverse the operations. The locking pin 64 is moved from the locked position ( FIG. 10 ) to the unlocked position ( FIG. 9 ). A user can then rotate the stinger assembly 20 approximately 30 degrees to the position illustrated in FIG. 7 . The stinger assembly 20 can then be axially withdrawn from the bore 60 of the breech lock connector 58 .
[0030] The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to those skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention. | Devices and methods for quickly connecting and disconnecting a conduit to a port. In a described embodiment, a quick connect coupling is described for quickly connecting and disconnecting a cement supply conduit to the port of a top drive cement swivel. | 4 |
TECHNICAL FIELD
The present invention relates to a heating furnace for heating a subject to be heated by radiation and a heating method employed by the heating furnace. More particularly, the present invention relates to a heating furnace capable of avoiding ignition and enhancing safety and a heating method employed by the heating furnace.
BACKGROUND ART
Heretofore, in a soldering process for bonding a semiconductor element or device to be used in a power module such as an IGBT (insulated gate bipolar transistor) element and others to a substrate through a solder, a hydrogen atmosphere is formed in a chamber serving as a process chamber and the process is conducted under reduced pressure of the atmosphere (for example, Patent Literature 1).
A typical hydrogen vacuum furnace has such a configuration as shown in FIG. 5 . Specifically, a hydrogen vacuum heating furnace 90 includes a process chamber 1 in which a subject 10 to be heated (“subject”) will be placed or set, a heating chamber 2 in which heater lamps 25 serving as a heating source are housed, and a crystal board 3 for separating the process chamber 1 and the heating chamber 2 . The process chamber 1 is provided with a feed port 11 for feeding hydrogen or a mixture gas of hydrogen and inert gas and an exhaust port 12 for discharging gas from the process chamber 1 . In the hydrogen vacuum furnace 90 , the subject 10 is heated by a radiant ray (an infrared ray or the like) from the heater lamp 25 .
The hydrogen vacuum furnace having the above configuration that separates the heater lamps from the subject to be heated provides the following merits as compared with a configuration in which a heater lamp is placed in a process chamber:
(1) The heater lamp which becomes an ignition source is separated from hydrogen or a mixture gas of hydrogen and inert gas; (2) The heater lamp is prevented from electrically discharging during heating under reduced pressure; (3) The heater lamp can be replaced with another one without contaminating the inside of the process chamber (Easy maintenance); (4) The volume of the process chamber is reduced (Reduced amount of gas to be used); (5) Impurities (flux contained in solder or the like) are prevented from sticking to the heater lamp; (6) The process chamber is prevented from contamination by impurities (a reflection film coated on the surface of the heater lamp or the like) from the heater lamp. Patent Literature 1: JP2005-205418A
SUMMARY OF INVENTION
Technical Problem
However, the aforementioned conventional hydrogen vacuum furnace 90 has the following disadvantages. Specifically, the crystal board 3 is sealed by sealing members 31 such as O-rings which tend to deteriorate with duration. This deterioration may break the sealing members 31 , resulting in insufficient sealing. Breakage of the sealing members 31 will cause hydrogen or a mixed gas of hydrogen and inert gas to rapidly flow from the process chamber 1 into the surrounding of each heater lamp 25 , which may become an ignition source.
The present invention has been made to solve the above problems of the aforementioned conventional heating furnace. Specifically, the present invention has a purpose to provide a heating furnace capable of avoiding ignition and enhancing the safety and a heating method employed by the heating furnace.
Solution to Problem
To achieve the above purpose, there is provided a heating furnace for heating a subject to be heated by radiation, comprising: a first chamber in which the subject will be placed, the first chamber including a gas feed port and a gas exhaust port; a second chamber placed adjacent to the first chamber and housing a heating source, and including a gas feed port and a gas exhaust port; and a separation member for separating the first chamber and the second chamber and allowing a radiant ray from the heating source to pass through, wherein atmosphere and atmospheric pressure in the first chamber and the second chamber are changed by feeding gas into and out of the first chamber and the second chamber through the feed ports and the exhaust ports.
In the heating furnace of the present invention, the first and second chambers are placed adjacently, and the radiant ray from the heating source in the second chamber is allowed to pass through the separation member separating both the chambers and be absorbed by the subject to be heated, thereby heating the subject. Each of the first and second chambers is provided with the gas feed port and the gas exhaust port for allowing gas feeding and exhausting. In other words, the chambers can be evacuated to create a vacuum or supplied with gas to perform atmosphere replacement and adjustment of atmospheric pressure.
Accordingly, for example, before the heating process of the subject to be heated, both the chambers are evacuated to remove oxygen from the chambers. The atmosphere of the second chamber is thus replaced with nitrogen. In this way, the second chamber is brought into the inert gas atmosphere and the oxygen concentration which is one of hydrogen ignition conditions is reduced, thereby avoiding firing.
In the heating furnace of the present invention, preferably, during a heating process of the subject, the atmospheric pressure in the second chamber is higher than the atmospheric pressure in the first chamber. Specifically, the inert gas (e.g., nitrogen) is fed into the second chamber. This brings the second chamber into a higher atmospheric pressure state than the first chamber. Even if a sealing member which seals a gap between the first and second chambers is broken, it is possible to prevent hydrogen in the first chamber from rapidly flowing in the second chamber during the heating process. This makes it possible to prevent the hydrogen and an ignition source from simultaneously exist in the second chamber and hence avoid firing.
Furthermore, in the heating furnace of the present invention, preferably, during the heating process of the subject, a flow of inert gas going from the feed port of the second chamber toward the exhaust port of the second chamber is formed. Specifically, the inert gas blowing process is performed in the second chamber. This blowing process can prevent a rise in atmospheric temperature of the second chamber. In association with this, the temperature rise of the separation member is also prevented. Since a highest temperature area in the first chamber is the separation member, the temperature rise in the first chamber is also prevented, which can prevent the appearance of an ignition source (410° C. or higher) which is one of ignition conditions, thus avoiding ignition in the first chamber.
Furthermore, preferably, the heating furnace of the present invention comprises a gas sensing section for detecting a first gas to be fed into the first chamber, the gas sensing section being located in the second chamber or in an exhaust path of gas to be discharged from the second chamber, wherein when the gas sensing section detects that the first gas is at a predetermined value or higher, safety control is performed to prevent content of the first gas in the second chamber from increasing.
Specifically, the gas sensing section detects the first gas (e.g., hydrogen) contained in the second chamber. When the predetermined value or higher is detected, the safety control is performed to prevent the content of the first gas in the second chamber from increasing. For example, the safety control may be performed by stopping feeding of the first gas into the first chamber. Alternatively, the safety control may be performed by increasing a flow velocity of inert gas to be fed into the second chamber. This makes it possible to prevent the concentration of the first gas in the second chamber from increasing and hence to avoid firing.
Furthermore, preferably, the heating furnace of the present invention, comprises: a first pressure gauge for detecting atmospheric pressure in the first chamber; a second pressure gauge for detecting atmospheric pressure in the second chamber; and a control section for controlling the atmospheric pressure in the first chamber and the atmospheric pressure in the second chamber based on measurement results of the first pressure gauge and the second pressure gauge, wherein the control section controls that, during the heating processing of the subject, the atmospheric pressure in the second chamber is higher than the atmospheric pressure in the first chamber and a pressure difference between the atmospheric pressure in the first chamber and the atmospheric pressure in the second chamber is a predetermined value or lower.
Specifically, the control section maintains a state where the pressure difference between the first and second chambers is small. Thus, the stress load on the separation member can be reduced and a reduction in the thickness of the separation member can be achieved. Accordingly, the distance between the heating source and the subject to be heated is shortened, thereby enhancing a heating efficiency. In addition, a cost reduction of the separation member itself can be achieved. Since absorbed energy by the separation member decreases, the temperature of the separation member 3 is prevented from rising.
According to another aspect, the present invention provides a heating method employed by a heating furnace for heating a subject to be heated by radiation, the heating furnace comprising a first chamber for accommodating the subject to be heated, a second chamber placed adjacent to the first chamber and housing a heating source, and a separation member for separating the first chamber and the second chamber and allowing a radiant ray from the heating source to pass through, the method comprising: a preparation step before delivering the subject to be heated into the first chamber, the preparation step including replacing inside of the second chamber with an inert gas atmosphere and then increasing atmospheric pressure in the second chamber than outside atmospheric pressure; an evacuation step after delivering the subject to be heated into the first chamber, the evacuation step including evacuating the first chamber to reduce the atmosphere thereof to a predetermined pressure; and a heating step after the first chamber is evacuated, the heating step including heating the subject to a predetermined temperature.
The aforementioned heating method employed by the heating furnace, preferably, comprises a blowing control step of keeping the second chamber at a predetermined atmospheric pressure and forming a flow of inert gas going from a feed port of the second chamber toward an exhaust port of the second chamber.
The aforementioned heating method employed by the heating furnace, preferably, comprises a pressure difference control step of controlling the atmospheric pressure in each of the first chamber and the second chamber in sync with variations in atmospheric pressure in the first chamber so that the atmospheric pressure in the second chamber is higher than the atmospheric pressure in the first chamber and a pressure difference between the atmospheric pressure in the first chamber and the atmospheric pressure in the second chamber is a predetermined value or lower.
The present invention can provide the heating furnace capable of avoiding ignition and enhancing safety and the heating method employed by the heating furnace.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a configuration view of a hydrogen vacuum furnace of a preferred embodiment;
FIG. 2 is a configuration view of a heating control system included in the hydrogen vacuum furnace of FIG. 1 ;
FIG. 3 is a graph showing profiles of temperature and pressure in a soldering process;
FIG. 4 is a configuration view of a heating vacuum furnace including a process chamber and a heating chamber separately provided; and
FIG. 5 is a configuration view of a hydrogen vacuum furnace in a prior art.
DESCRIPTION OF EMBODIMENTS
A detailed description of a preferred embodiment of a heating furnace embodying the present invention will now be given referring to the accompanying drawings. In this embodiment, the present invention is applied to a hydrogen vacuum furnace to be used in a process for soldering an IGBT element to a ceramic substrate.
<Configuration of Hydrogen Vacuum Furnace>
A heating vacuum furnace 100 of this embodiment includes, as shown in FIG. 1 , a process chamber 1 in which a subject 10 to be heated (simply, a “subject”) will be placed or set for a soldering process of the subject 10 , a heating chamber 2 in which heater lamps 25 serving as a heating source are arranged, a crystal board 3 which separates the subject 10 and the heater lamps 25 from each other, and a safety valve 4 which is to be opened when the inner pressure of the process chamber 1 reaches a predetermined atmospheric pressure or higher. In the hydrogen vacuum furnace 100 , the subject 10 is heated with radiant rays emitted from the heater lamps 25 .
The subject 10 is constituted of an IGBT element, a ceramic substrate, and a solder pellet bonding the IGBT element to the ceramic substrate. The IGBT element is made by a well known semiconductor manufacturing technique. The solder is Pb-free solder that does not substantially containing lead (in this embodiment, Sn—In, Sn—Cu—Ni, Sn—Cu—Ni—P, Sn—Ag—Cu, etc.). The subject 10 is held at its end by a holder member not shown.
The process chamber 1 is provided with a feed port 11 for supplying hydrogen or a mixture gas of hydrogen and inert gas (nitrogen in this embodiment) to the process chamber 1 , an exhaust port 12 for discharging gas from the process chamber 1 , and a thermometer 14 for measuring the temperature of the subject 10 .
The heating chamber 2 is provided with a feed port 21 for feeding inert gas (nitrogen in this embodiment) into the heating chamber 2 , an exhaust port 22 for discharging gas from the heating chamber 2 , heater lamps 25 (halogen lamps in this embodiment) which emit radiant rays (infrared rays in this embodiment) in a predetermined wavelength range, and a reflection plate 26 having a paraboloidal surface which reflects the radiant rays emitted from the heater lamps 25 . The reflection plate 26 is placed in such a position as to reflect the radiant rays from the heater lamps 25 toward the process chamber 1 .
The crystal board 3 is a crystal glass plate of 400 mm in length, 400 mm in width, and 10 mm in thickness, located between the process chamber 1 and the heating chamber 2 to partition them. The crystal board 3 has a function of allowing the radiant rays emitted from the heater lamps 25 to pass through. An edge portion of the crystal board 3 is held between retaining parts 13 and 23 formed on wall surfaces of the process chamber 1 and the heating chamber 2 . O-rings 31 are placed to seal gaps between the retaining pars 13 and 23 and the crystal board 3 , thereby ensuring gas-tightness between the process chamber 1 and the heating chamber 2 .
<Configuration of Heating Control System>
A heating control system including the hydrogen vacuum furnace 100 of this embodiment includes, as shown in FIG. 2 , mass flow controllers (MFC) 61 and 62 , various valves 63 , 64 , 65 , 66 , 67 , 74 , 75 , 76 , 77 , pressure gauges (PG) 71 and 72 , a pump (P) 73 , and a control section 5 for controlling operation of each device.
To be concrete, the process chamber 1 is fed with hydrogen (H 2 ) gas. A hydrogen feed system includes the valve 66 , the MFC 61 , and the valve 63 arranged in this order in a hydrogen feeding direction to feed hydrogen gas into the process chamber 1 through the feed port 11 thereof. The heating chamber 2 is supplied with nitrogen (N 2 ) gas. A nitrogen feed system includes the valve 67 , the MFC 62 , and the valve 64 arranged in this order in a nitrogen feeding direction to feed nitrogen gas into the heating chamber 2 through the feed port 21 thereof. Furthermore, a branch passage extends from between the MFC 62 and the valve 64 to communicate with the hydrogen feed system through the valve 65 . In other words, in this system, nitrogen is allowed to be fed into the process chamber 1 according to the on-off operation of the valve 65 . A feed amount of each gas is controlled by the MFCs 61 and 62 .
Atmospheres in the process chamber 1 and the heating chamber 2 are sucked by the pump 73 . Specifically, an exhaust system of the process chamber 1 includes the valves 75 and 77 , and the pump 73 arranged in this order from the side of the exhaust port 12 of the process chamber 1 . On the other hand, an exhaust system of the heating chamber 2 includes the valves 76 and 77 , and the pump 73 arranged in this order from the side of the exhaust port 22 of the heating chamber 2 . That is, the pump 73 and the valve 77 are used in common for exhaust of the process chamber 1 and the heating chamber 2 . Furthermore, a leak valve 74 is placed downstream from the exhaust port 22 to carry out nitrogen blowing by the on-off operation of the valve 74 .
In the exhaust system of the process chamber 1 , the pressure gauge 71 is placed downstream from the exhaust port 12 of the process chamber 1 . This measures atmospheric pressure in the process chamber 1 . On the other hand, in the exhaust system of the heating chamber 2 , the pressure gauge 72 is placed downstream from the exhaust port of 22 of the heating chamber 2 . This measures atmospheric pressure in the heating chamber 2 . Measurement results of the pressure gauges 71 and 72 are transmitted to the control section 5 .
In the exhaust system of the heating chamber 2 , a hydrogen sensor 78 is placed downstream from the exhaust port 22 of the heating chamber 2 to detect hydrogen concentration in the atmosphere in the heating chamber 2 . A measurement result of the hydrogen sensor 78 is transmitted to the control section 5 .
<Soldering Procedure>
The following explanation is given to operation procedures of the soldering process utilizing the heating control system of this embodiment. In the following explanation, two operation procedures are described by assuming a first mode as a basic example and a second mode as an application.
<First Mode>
Firstly, before delivery of the subject 10 as a workpiece, pre-operation preparation is conducted by nitrogen replacement of both the process chamber 1 and the heating chamber 2 (Step 1 ). Specifically, both chambers are evacuated by the pump 73 . Then, both chambers are supplied with nitrogen to thereby purge oxygen from both chambers until the oxygen concentration is reduced to 10 ppm or lower. Thus, a nitrogen atmosphere is created in each chamber.
Subsequently, while the leak valve 74 is controlled to keep atmospheric pressure in the heating chamber 2 at 1.1 atm, nitrogen is fed at 20 liters/min. into the heating chamber 2 (Step 2 ). In the heating chamber 2 , accordingly, nitrogen gas is caused to flow from the feed port 21 toward exhaust port 22 , forming a gas flow (hereinafter, this process is referred to as “nitrogen blowing process”). In this step 2 , the pre-operation preparation is finished, oxygen is removed from both chambers, and the atmospheric pressure in the heating chamber 2 becomes higher than outside atmospheric pressure.
Subsequently, the procedure goes to the soldering process where the following operations are conducted. The subject 10 is first delivered into the process chamber 1 (Step 3 ). The nitrogen atmosphere in the process chamber 1 is replaced with hydrogen (Step 4 ). In other words, the process chamber 1 is evacuated by the pump 73 . Then, the process chamber 1 is supplied with hydrogen to create a hydrogen atmosphere in the process chamber 1 .
Subsequently, the heater lamps 25 are tuned on to heat the subject 10 up to a preheating target temperature (200° C. in this embodiment) lower than a melting point of solder (solder solidus temperature of 235° C.). After that, the heater lamps 25 are turned off to keep the temperature for a predetermined time (Step 5 ). This preheating cleans up the surface of the subject 10 .
For compressing bubbles in the solder or other purposes, the process chamber 1 is evacuated to 2 kPa (Step 6 ). This largely reduces the atmospheric pressure in the process chamber 1 than the atmospheric pressure in the heating chamber 2 . Thereafter, the subject 10 is heated up to a final target temperature (280° C. in this embodiment) higher than the solder melting point (solder liquidus temperature of 240° C.) (Step 7 ). By this main heating, the solder melts, wet and spread to a predetermined area.
The heater lamps 25 are turned off, the inside of the process chamber 1 is replaced with nitrogen again so as to return to the outside atmospheric pressure (Step 8 ). Then, the subject 10 is cooled to near room temperature, solidifying the solder. The soldering process is thus completed. The subject 10 is then delivered out. In this way, in the soldering process (Steps 3 to 8 ), the atmospheric pressure in the heating chamber 2 is kept to be higher than the atmospheric pressure in the process chamber 1 .
It is to be noted that, during the nitrogen blowing process, a flow rate of hydrogen is detected by the hydrogen sensor 78 . In other words, it is detected whether or not the hydrogen fed into the process chamber 1 leaks in the heating chamber 2 . If the hydrogen is detected to be a predetermined value or higher, safety control is performed to prevent a rise in the content of hydrogen in the heating chamber 2 , thereby avoiding ignition even if a slight amount of hydrogen flows in the heating chamber 2 .
The safety control is carried out for example by urgently stopping the heater lamps 25 to make the existence of the ignition source disappear or by increasing the flow rate of nitrogen in the nitrogen blowing process to purge hydrogen from the heating chamber 2 . In other words, a condition where the hydrogen and the ignition source exist simultaneously is prevented from occurring.
In the soldering process of this embodiment explained above in detail, the pre-operation preparation is conducted by evacuating both chambers to remove oxygen from both chambers (Step 1 ), thereby replacing the atmosphere in both chambers with nitrogen. Therefore, particularly in the heating chamber 2 , an inert gas atmosphere is created with reduced oxygen concentration, thus ensuring avoidance of ignition.
In this embodiment, furthermore, during the heating process of the subject 10 , the atmospheric pressure in the heating chamber 2 is higher than the atmospheric pressure in the process chamber 1 . Specifically, the atmospheric pressure in the heating chamber 2 is increased by feeding nitrogen into the heating chamber 2 (Step 2 ). In the process chamber 1 , on the other hand, the heating process is conducted under reduced pressure (Step 6 ). Accordingly, during the heating process of the subject 10 , the heating chamber 2 is under positive pressure with respect to the process chamber 1 . Even if the sealing members 31 are broken, hydrogen in the process chamber 1 is prevented from rapidly flowing in the heating chamber 2 . The hydrogen and the ignition source are therefore prevented from simultaneously exist in the heating chamber 2 , thus avoiding ignition.
In this embodiment, during the heating process of the subject 10 , the nitrogen blowing process is conducted (Step 2 ) to thereby prevent a rise in atmospheric pressure in the heating chamber 2 . This also prevents a rise in temperature of the crystal board 3 . A highest temperature area in the process chamber 1 is the surface of the crystal board 3 and thus the temperature rise in the process chamber 1 is also prevented, thereby preventing the appearance of the ignition source (410° C. or higher) which is one of ignition conditions, thus avoiding ignition.
In this embodiment, furthermore, oxygen in the heating chamber 2 is removed down to 10 ppm or lower. It is therefore possible to prevent deterioration of the heater lamps 25 by oxidation. In this embodiment, particularly, the halogen lamp is utilized and accordingly oxidation of the sealing members of the heater lamps 25 will largely influence the heater life. Thus, preventing oxidation is particularly effective in achieving a long life.
<Second Embodiment>
In this embodiment, a soldering process is conducted by controlling the atmospheric pressure in each chamber so that the atmospheric pressure in the heating chamber 2 follows variations in atmospheric pressure in the process chamber 1 and is constantly positive pressure with respect to the process chamber 1 . This configuration is different from that in the first embodiment where close pressure control is not conducted.
Operations in the soldering process in this embodiment will be explained below with reference to a graph in FIG. 3 showing profiles of temperature and pressure. The operation for pre-operation preparation is the same as in the first embodiment.
Firstly, from the time of delivery of the subject 10 to the time t 0 , pre-heating is performed by heating the subject 10 to the pre-heating target temperature. During this period, the inside of the heating chamber 2 is kept at a higher atmospheric pressure than in the process chamber 1 . By the nitrogen blowing process, the atmosphere in the heating chamber 2 is refreshed at all times. This makes it possible to prevent the atmospheric temperature in the heating chamber 2 and the temperature of the crystal board 3 from rising.
Subsequently, from the time t 0 to the time t 1 , the atmospheric pressure in the process chamber 1 is reduced to 1 kPa. At that time, in the heating chamber 2 , the nitrogen blowing process is also stopped and the pressure is reduced to 2 kPa in sync with the vacuum timing to prevent a pressure difference between both chambers from exceeding 1 kPa. The pressure of each chamber is measured by the pressure gauge 71 or 72 . Based on each measurement result, the control section 5 controls the pressure of each chamber. To be concrete, the pressure control during pressure rise is performed by the MFCs 61 and 62 and the pressure control during pressure drop is performed by on-off operations of the vacuum valves 75 , 76 , and 77 .
Then, from the time t 1 to the time t 2 , main heating is performed by heating the subject 10 to the final target temperature. During this period, the heating causes the temperature of the process chamber 1 to gradually rise. Accordingly, the process chamber 1 is evacuated as needed to perform fine control to prevent the pressure difference from the heating chamber 2 from exceeding 1 kPa.
After the time t 2 , the heater lamps 25 are turned off and nitrogen is fed into both chambers to return the inside of the process chamber 1 to outside atmospheric pressure. At this time, an amount of nitrogen to be supplied is controlled to prevent the pressure difference between the heating chamber 2 and the process chamber 1 from exceeding 1 kPa. The subject 10 is then cooled to near room temperature to solidify the solder. The soldering process is thus terminated. Thereafter, the subject 10 is carried out.
In the soldering process in this embodiment, the control section 5 performs pressure control to keep the pressure difference in atmospheric pressure between the process chamber 1 and the heating chamber 2 from exceeding 1 kPa. This makes it possible to reduce stress load on the crystal board 3 , thereby achieving a reduction in the thickness of the crystal board 3 . Specifically, in the first embodiment, the crystal board 3 needs to have a thickness of about 10 mm, whereas the crystal board 3 has only to have a reduced thickness of about 5 mm. Accordingly, the distance between each heater lamp 25 and the subject 10 is shortened, thereby enhancing a heating efficiency. Cost of the crystal board 3 itself can also be reduced. Since absorbed energy by the crystal board 3 decreases, the rise in temperature of the crystal board 3 is prevented.
The above embodiments are merely examples that do not give any limitations to the present invention. The present invention may be embodied in other specific forms without departing from the essential characteristics thereof. For instance, in the above embodiments, the process chamber 1 and the heating chamber 2 are configured as an integral chamber in which the crystal board 3 is placed to partition the inside thereof, but not limited thereto. For instance, as shown in FIG. 4 , a heating box 20 which can be reduced in pressure may be attached to the process chamber 1 . That is, the process chamber 1 and the heating chamber 2 may be configured separately.
Although the pressure gauges 71 and 72 and the hydrogen sensor 78 are placed outside the process chamber 1 and the heating chamber 2 , they are not limited therein and may be placed inside the process chamber 1 or the heating chamber 2 .
The heating sources 25 may be selected from not only the halogen lamps but also carbon heaters, ceramic heaters, etc. The separation member for separating the process chamber 1 and the heating chamber 2 is not limited to the crystal board and may be a transparent ceramic or the like.
The subject 10 is not particularly limited and may be selected from not only the power IC such as IGBT element and a ceramic substrate but also a resistor element, a condenser element, a printed circuit board, etc., if only it can be processed by heat in the hydrogen vacuum furnace. Furthermore, the kind of solder is not limited to the Pb-free solder. | A hydrogen vacuum furnace ( 100 ) is provided with a process chamber ( 1 ) wherein a subject ( 10 ) to be heated is stored; a heating chamber ( 2 ) wherein a heater lamp ( 25 ) is stored; and a crystal board ( 3 ) for separating the subject ( 10 ) and the heater lamp ( 25 ) one from the other. In the hydrogen vacuum furnace ( 100 ), the subject ( 10 ) is heated by a radiant ray applied from the heater lamp ( 25 ). The process chamber ( 1 ) and the heating chamber ( 2 ) are provided with gas feed ports ( 11, 21 ) and exhaust ports ( 12, 22 ), respectively, for feeding and exhausting a gas. When the subject ( 10 ) is being heated, atmospheric pressure in each chamber is adjusted so that the heating chamber ( 2 ) is under positive pressure to the process chamber ( 1 ) by feeding or exhausting the gas. | 5 |
BACKGROUND OF THE INVENTION
The invention relates to a profiled cutter head having cutters which can be resharpened without changing the profile and trajectory, which cutter head has the features of the preamble of claim 1.
BRIEF DESCRIPTION OF THE INVENTION
In a known profiled cutter head of this kind (G 69 33 019), each cutter support is clamped by means of screws against the base of the recess accommodating it in the basic body. Radially inside the cutter fixed to the cutter support, the cutter support has a bead-like protrusion which engages deeper into a groove in the basic body the smaller the thickness of the cutter becomes owing to its being ground away on its front for the purpose of resharpening. As soon as the engagement in the groove is free from play, this positive lock allows at least some of the centrifugal forces acting on the cutter to be taken up and thus makes it possible to prevent an increase in the trajectory owing to centrifugal force. However, fitting of this kind is complicated in terms of production engineering. Moreover, the screws have to be tightened carefully.
OBJECT OF THE INVENTION
The object underlying the invention is to provide a profiled cutter head having cutters which can be resharpened without changing the profile and trajectory, which cutter head has advantages over the known profiled cutter heads of the type discussed and in particular can be realized without expensive construction means. This object is achieved by a profiled cutter head having the features of claim 1.
A profiled cutter head of this kind does not require any special fitting. The cutter support and the cutter fixed thereto are positioned without fitting measures exclusively by means of the flanks, which form the bearing surfaces for the transverse part of the foot of the cutter support, of the grooves provided in the basic body and by means of the frontal stop surface. A positive lock which is free from play is then present in the direction in which the centrifugal force and the cutting force act. A further significant advantage consists in the fact that the force of the setscrew or setscrews, like the centrifugal force, presses the cutter support with its cutter against the surfaces serving for positioning, for which reason the centrifugal force is unable to bring about any change in position. The cutter head is therefore able to withstand high dynamic loads. This contributes to cost-effective production. Resharpening is carried out on the front of the cutter and can therefore be performed in a simple manner. Furthermore, the tool according to the invention makes it possible to achieve high cutting rates, long total tool paths and an excellent cutting quality. The cutter material can be utilized virtually completely, so that there is no need to throw away valuable cutting material. Furthermore, the basic body can be reused. The same cutter supports can be used for various profiles. Due to the exchangeability of the cutter supports, a modular system is obtained. Tool geometries and cutting materials which are adapted to the material can therefore be used without problems. The chip space can be configured optimally, as a result of which the dust fraction produced during the machining of wood can be significantly reduced.
Due to the fact that precise positioning of the cutter is inevitably achieved during clamping of the cutter support, a tool change is easy to carry out. The play-free positioning of the cutter ensures a high degree of accuracy during repeat positioning. The basic body may optionally consist of steel or aluminium, aluminium leading to a lower residual imbalance and thus protecting the bearings of the mounting spindle of the machine. The fact that it is possible to select large axis angles for a low power consumption and that the rake angle can be adapted to the material contributes further to a low machine loading.
The play-free positive lock of the cutters results in a high level of safety for the user and a high level of operational reliability. The feed can take place mechanically or manually. Furthermore, the tool according to the invention is maintenance-friendly. Simple and error-free resharpening can take place in a sharpening device. The tool is easy to clean, owing to a closed design. Large setscrews which are easy to undo prevent overtightening.
The solution according to the invention can be applied not only to cutter heads with disk- or bowl-like basic bodies but also to cutter heads with an offset, i.e. bell-like, basic body, the receptacles of which are open towards the ring-disk-like end face.
The cutter head according to the invention can be used for profiling and joining, specifically both as a single tool and as a set of tools comprising a plurality of individual tools. The cutters are preferably super-high-speed steel- Stellite- or carbide-tipped cutters on the frontal stop surface 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a preferred embodiment, that region of the receptacle which accommodates the foot has a T-shaped cross-sectional profile, the transverse part of which is formed by the two longitudinal grooves, the flanks of which, serving to support the foot of the cutter support, preferably then lie in one and the same plane. The extent to which the two arms of the foot can be displaced in the longitudinal grooves in the direction of their depth and to which the longitudinal part of the foot can be displaced in the longitudinal part of that region of the receptacle which accommodates the foot is selected here to be at least equal to the thickness of the layer of the cutter which can be ground off during resharpening. The cutter material can therefore be virtually completely consumed during resharpening. The reduction in the cutter thickness owing to resharpening has no effect on the positioning of the cutter and its support and on the play-free positive lock between the cutter support and the basic body. The maximum permissible removal of material from the front of the cutter during resharpening can be determined in a simple manner by allowing the longitudinal part of the foot to come to bear against the limit surface, which adjoins the frontal stop surface, of the longitudinal part of the receptacle when the cutter has reached its minimum thickness. As long as there continues to be a gap between these two surfaces, the cutter can be resharpened.
The positioning surfaces formed by the flanks of the groove preferably run at a right angle to a radial plane. Furthermore, the angle which the frontal stop surface and the neighbouring positioning surface include, like the angle which the clamping surface of the cutter support and the neighbouring positioning surface include, is preferably less than 80°.
Preferably, it is not the setscrew which bears against the clamping surface of the cutter support, but rather the end face of a pressure pin which is guided in a bore, which runs perpendicular to the clamping surface, in the basic body. If it is not possible, in particular for reasons of space, for the pressure screw to be arranged coaxially with the pressure pin, that end of the pressure pin which is remote from the clamping surface is bevelled. The longitudinal axis of the clamping screw then runs perpendicular to this inclined surface, the wedge angle of the inclined surface with respect to the longitudinal axis of the pressure pin preferably being selected to be greater than 30°.
The profiled cutter head according to the invention is suitable not only for embodiments in which the axis angle is zero, i.e. the longitudinal axis of each recess runs parallel to the central longitudinal axis of the basic body, but rather it is possible to provide axis angles different from zero, it being possible to retain the cross-sectional profile of the receptacles and the cutter supports, i.e. there is no need to make a major change either to the receptacles in the basic body or to the cutter support.
In a preferred embodiment, an axial stop which protrudes beyond the cross-sectional profile of the cutter support is fixed to the foot thereof for positioning in the axial direction.
If the profiled cutter head according to the invention is designed not as a tool with a central receiving bore but rather as a shank tool, it is preferred for one end face of the basic body to bear against an end face of the shank, concentrically thereto. This end face of the shank is advantageously provided on a flange-like end which has a greater diameter than the remaining part of the shank. Furthermore, it is advantageous if, in the case of such a shank tool, the basic body has a centring peg which projects beyond the end face bearing against the shank, which centring peg engages without play in a centring bore in the shank. Axially parallel through bores, which are aligned with threaded bores of the flange-like end section of the shank and accommodate connecting screws, may be provided in the basic body for connecting the basic body to the shank.
The invention is explained in detail below with reference to exemplary embodiments depicted in the drawing, in which:
FIG. 1 shows an end view of a first exemplary embodiment,
FIG. 2 shows an end view, illustrated incompletely and partially in cross-section, of the first exemplary embodiment with the tool in the as-new condition,
FIG. 3 shows an end view, illustrated incompletely and partially in cross-section, of the first exemplary embodiment at the end of the resharpening path,
FIG. 4 shows a view, illustrated diagrammatically and in perspective and also incompletely, of a second exemplary embodiment with an axis angle different from zero and a rectilinear cutting blade,
FIG. 5 shows a view, illustrated diagrammatically and in perspective and also incompletely, of a third exemplary embodiment with an axis angle different from zero and a profiled cutter,
FIG. 6 shows another view, illustrated in perspective, of the exemplary embodiment in accordance with FIG. 5 with the cutter removed from the basic body in the axial direction,
FIG. 7 shows a side view, illustrated incompletely and partially in section, of a fourth exemplary embodiment in the form of a shank tool,
FIG. 8 shows an incomplete end view, illustrated partially in section and on an enlarged scale, of the exemplary embodiment in accordance with FIG. 7,
FIG. 9 shows an end view, illustrated incompletely and partially in section, of a modification to the exemplary embodiment in accordance with FIGS. 7 and 8.
The exemplary embodiment depicted in FIGS. 1 to 3 of the profiled cutter head according to the invention has a basic body 2, which is provided with a central bore 1 for receiving a shaft, is made of steel or aluminium and in which two receptacles 3 are made, which receptacles are of identical design and are arranged diametrically with respect to the central bore 1. Since the axis angle in this cutter head is zero, the receptacles 3 run parallel to the longitudinal axis of the basic body 2. Its cross-sectional profile is composed of a trapezoidal region which widens towards the outer circumferential surface and a T-shaped region, the longitudinal part of which extends radially inwards from the trapezoidal region towards the transverse part formed by two longitudinal grooves 4 and 5. The two longitudinal grooves 4 and 5, which are open towards one another, are bounded radially to the outside by a first positioning surface 6 and a second positioning surface 7, respectively, both of which lie in the same plane which, together with a radial plane, includes an angle of 90°. The first positioning surface is adjoined at right angles by a limiting surface 8 which is adjoined by a frontal stop surface 9, which is inclined with respect to a radial plane by the rake angle. In the exemplary embodiment, one edge of a chip removal groove 10 made in the basic body 2 adjoins the frontal stop surface 9.
Together with the frontal stop surface 9, a likewise planar side surface 11 of the receptacle 3 includes an angle of slightly less than 90° and is adjoined by a limiting surface 12, which runs parallel to the limiting surface 8 and on the other side adjoins the second positioning surface 7. As shown in particular by FIGS. 2 and 3, the radial extent of the limiting surface 12 is significantly less than that of the limiting surface 8, due to the fact that the side surface 11 is significantly wider than the frontal stop surface 9.
A cutter support 14, which is equipped with a resharpenable cutter 13 and the axial length of which may be greater than that of the basic body 2, is inserted into each of the receptacles 3. The two identically formed cutter supports 14, which are preferably cut to length from a correspondingly profiled bar, have a head part, against whose surface which is situated at the front in the running direction the cutter 13, which is soldered onto the cutter support 14, bears. The surface which delimits the cutter support 14 on the outside is profiled in the same way as the cutter 13. Since in the exemplary embodiment in accordance with FIGS. 1 to 3 the cutting edge is rectilinear, this surface lies in the plane defined by the flank of the cutter 13. Towards the side surface 11, the head region of the cutter support 14 is delimited by a planar clamping surface 15 running parallel to the side surface 11.
The head region of the cutter support 14 is adjoined radially on the inside by a T-shaped foot region, the transverse part of which forms a first arm 16 engaging in the longitudinal groove 4 and a second arm 17 engaging in the longitudinal groove 5. As shown by FIGS. 2 and 3, the thickness of the arms 16 and 17 is less than the width of the longitudinal grooves 4 and 5. The first arm 16 is delimited radially on the outside by a stop surface 16' and the second arm 17 is delimited radially on the outside by a stop surface 17'. The stop surface 16' is intended to bear against the first positioning surface 6, and the stop surface 17' to bear against the second positioning surface 7. Like the positioning surfaces 6 and 7, the two stop surfaces 16' and 17' lie in one and the same plane.
As also shown by FIGS. 2 and 3, the distance between the limiting surface 8 and the limiting surface 12 of the basic body 2 is larger by slightly more than the resharpening path than the thickness, measured in this direction, of the longitudinal part of the foot of the cutter support 14. In the as-new state of the cutter 13, the longitudinal part of the foot is at only a small distance from the limiting surface 12 of the receptacle 3. As the thickness of the cutter 13 decreases owing to the resharpening, the central part of the foot comes ever closer to the limiting surface 8 until at the minimum thickness of the cutter it is only a distance of about 0.2 mm from the limiting surface 8. This thin gap indicates that the cutter 13 can no longer be sharpened further. As the thickness of the cutter decreases, the first arm 16 penetrates ever further into the longitudinal groove 4 during positioning of the cutter support 14, while the second arm 17 is moved further and further out of the longitudinal groove 5. However, the two arms 16 and 17, both with the maximum and minimum thickness of the cutter, still engage sufficiently deep into the longitudinal grooves 4 and 5, respectively, to position the cutter 13 by bearing against the positioning surfaces 6 and 7, respectively, and, for the forces acting on the said cutter and on the cutter support 14, to join to the basic body 2 in a positively-locking manner.
Starting from the side surface 11, a number of blind bores 18 penetrate into the basic body 2, perpendicular to the side surface 11, which number is dependent on the axial length of the basic body 2 and of the cutter support 14; if a plurality of these blind bores 18 are provided, their longitudinal axis lies in a plane parallel to the longitudinal axis of the basic body 2. A pressure pin 19, one end face of which bears against the clamping surface 15 of the cutter support 14, is arranged longitudinally displaceably in each blind bore 18. The end remote from this end forms an inclined surface 20 which, together with the longitudinal axis of the pressure pin 19, includes an angle of more than 30°. This inclined surface 20 is adjoined by the end face of a setscrew 21, which is situated in a threaded bore, running perpendicular to the inclined surface 20, of the basic body 2. The inclined surface 20 converts the screw force acting in the longitudinal direction of the setscrew 21 into a clamping force acting in the longitudinal direction of the pressure pin 19.
As shown in FIG. 1, in order to position the cutter support 14 and the cutter 13 in the axial direction, a disk-like axial stop 22 is fixed, specifically by means of a screw in the exemplary embodiment, to one end face of the cutter support 14 in the region of the free end of the first arm 16. When the cutter support 14 is correctly positioned, this axial stop 22 bears against the end face of the basic body 2 in the region of the longitudinal groove 4.
When the cutter support 14 has reached its correct axial position and the setscrew or setscrews 21 are tightened, the cutter support 14 is initially pushed to the left, when viewed in accordance with FIGS. 1 to 3, until the front surface 13' of the cutter 13 bears against the frontal stop surface 9 of the basic body 2. The force of the setscrews 21 then has the effect of pressing the stop surfaces 16' and 17' of the arms 16 and 17, respectively, onto the positioning surfaces 6 and 7, respectively. The cutter support 14 and the cutter 13 are now positioned, without additional fittings, precisely, due to the fact that there is no play, and moreover in a positively-locking manner with respect to the clamping force and the centrifugal force. The cutter support 14 and the cutter 13 are also connected in a positively-locking manner to the basic body 2 with regard to the cutting force. The tool can therefore be subjected to high dynamic loads.
To resharpen the cutter 13, the setscrews 21 merely have to be loosened slightly. The cutter support 14 can then be removed from the receptacle 3 in the axial direction. After resharpening, which does not lead to any change in the profile, because the resharpening takes place on the front surface 13' of the cutter 13, precisely the same trajectory is achieved again, because the cutter support 14 is displaced towards the frontal stop surface 9, with respect to the previous positioning, only by the resharpening distance and, moreover, the positioning and positively-locking connection to the basic body 2 are unchanged.
The exemplary embodiment in accordance with FIG. 4 differs from that in accordance with FIGS. 1 to 3 only in that it has an axis angle which is different from zero. The limiting surfaces of the recesses 103 of the basic body 102 are merely rotated through the axis angle in the plane of the flank. The cross-sectional profile of both the recess 103 and of the cutter support 114 are therefore unchanged by comparison with the exemplary embodiment in accordance with FIGS. 1 to 3. Reference can therefore be made to the first exemplary embodiment with regard to the further design of the basic body 102, the cutter support 114 and the cutter 113.
The cutter support 114 can be cut from the same section bar as the cutter support 14. It is merely necessary here for the plane of the cut to be offset by the axis angle with respect to a cross-sectional plane. FIG. 4 also shows that the cutter support 114, together with the cutter 113, can project beyond one end face of the basic body 102.
The exemplary embodiment depicted in FIG. 5 differs from that in accordance with FIG. 4 essentially only in that each cutter 213 and, in the same way, the head part of each cutter support 214, is profiled. This profile too does not change as a result of resharpening of the cutter 213 on its front surface 213'. The trajectory too does not change as a result of the resharpening. As shown by FIG. 6, the axis angle which is different from zero makes it necessary to provide a pocket in the clamping surface 215 of the cutter support 214 for each pressure pin, which pocket forms a stop surface 215', lying parallel to the end face of the pressure pin, for the end face of the pressure pin. The two setscrews, which are each arranged in a threaded bore of the basic body 202, are denoted by 221, while the axial stop of the cutter support 214 is denoted by 222. Reference is made to the exemplary embodiment in accordance with FIGS. 1 to 3 with regard to the remaining details, since in this respect the third exemplary embodiment is identical to the first exemplary embodiment.
In contrast to the exemplary embodiments in accordance with FIGS. 1 to 6, which involve tools with a bore, FIGS. 7 and 8 show a shank tool.
A cylindrical shank 323 has at its end a cylindrical flange 324 and at its other end a central threaded bore, into which a screw 326 can be screwed. One end face of a basic body 302 of a profiled cutter head bears against the free end face of the flange 324. For centring purposes, a central centring peg 327 protrudes beyond this end face of the basic body 302 and engages without play in a central centring bore 328 of the flange 324. Two through bores, which lie diametrically with respect to the longitudinal axis of the tool, of the basic body 302 are in each case aligned with a threaded bore 325 of the flange 324. Screws 329 clamp the basic body 302 against the flange 324 without play.
The basic body 302 is provided with two diametrically arranged, identically designed receptacles 303, which, as FIG. 8 shows, have the same shape as the receptacles 3 of the first exemplary embodiment. The associated cutter supports 314 also have essentially the same shape as the cutter support 14. In particular, the play-free connection, which is positively locking for the clamping force and the centrifugal force and the cutting force, between the cutter support 314 and the basic body 303 is carried out, as in the exemplary embodiments described above, by means of the two positioning surfaces 306 and 307, the frontal stop surface 309 and the clamping surface 315. The cutter 313 soldered onto the cutter support 314 is a tip made of sintered carbide, Stellite or super-high-speed steel. The layer of solder is noted by 330.
As shown in FIG. 8, the spatial conditions allow the setscrews 321 in the basic body 302 to be arranged coaxially with the associated pressure pins 319.
When the setscrews 321 are tightened, the clamping force, which is transmitted via the pressure pin 319 to the cutter support 314 and runs approximately parallel to the frontal surface 313' of the cutter 313, has the effect of bringing the cutter 313 to bear against the frontal stop surface 309 and then of pressing the stop surfaces 316' and 317' against the two positioning surfaces 306 and 307.
Instead of arranging the pressure pin and the setscrew to form an angle which opens towards the circumferential surface of the basic body, as is the case in the exemplary embodiment s in accordance with FIGS. 1 to 6, or instead of a coaxial arrangement as in the exemplary embodiment in accordance with FIGS. 7 and 8, it is possible, if spatial conditions in the basic body 402 allow, also to arrange the pressure pin 419 and the setscrew 421 such that they form an angle which opens towards the centre of the basic body 402, as shown by FIG. 9. | In a profiled inserted-blade cutter, with blades (13) which can be re-sharpened without altering the profile and trajectory, each blade (13) is secured to a blade holder (14) having a base with a T-shape cross section, one arm (16) of the transverse section of which engages in a first longitudinal groove (4) in the basic unit (2). The other arm (17) engages in a second longitudinal groove (5) also in the basic unit (2) and open towards the first groove (4). The flanks of the first and second longitudinal grooves (4, 5) at a greater distance from the central longitudinal axis of the basic unit (2) lie in planes which are mutually parallel and parallel to the longitudinal axis of the basic unit and each form a positioning surface (6, 7) for one or other arm (16, 17) of the transverse section. On the blade holder (14) there is a clamping surface (15) which encloses a radially outwardly opening angle with the frontal surface (13') of the blade (13) and an acute angle with the adjacent positioning surface (7). The clamping force of each clamping screw (21) is directed against the clamping surface (15) and presses the blade holder (14) with a first component against the frontal stop surface (9) and with a second component against the two positioning surfaces (6, 7). | 8 |
RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application Ser. No. 10/715,430, Embedded Barrier to Fluid Flow, by McInerney et al., filed Nov. 19, 2003, and incorporated herein by reference.
STATEMENT OF GOVERNMENT INTEREST
[0002] Under paragraph 1(a) of Executive Order 10096, the conditions under which this invention was made entitle the Government of the United States, as represented by the Secretary of the Army, to the entire right, title and interest therein of any patent granted thereon by the United States. This patent and related ones are available for licensing. Contact Bea Shahin at 217 373-7234 or Phillip Stewart at 601 634-4113.
BACKGROUND
[0003] U.S. Pat. No. 6,286,279, Method for Attaching Fabric and Floor Covering Materials to Concrete, to Bean et al., Sep. 11, 2001, and incorporated herein by reference, teaches bonding a thin metal plate or metal foil to a concrete surface to effect a barrier to water vapor transfer. The configuration of the '279 patent improves the maintenance of the bond between a concrete surface and various types of floor coverings. The '279 patent teaches two systems for implementing the barrier: one uses a single-layered thin metal plate or metal foil that is folded to produce recesses much like corrugated sheet metal. One side of the foil is attached to the concrete surface using a Portland cement-based thin set grout. A second embodiment employs a two-part thin metal plate or foil. A first lower part is perforated (or slit and expanded) and attached to a second solid upper part. The lower perforated part is embedded in a layer of thin set mortar on the concrete to anchor it to the concrete. The thin set mortar that oozes through the perforations also serves as a mechanical bond, a “cementitious rivet,” supplementing the chemical bond made along the contact surface.
[0004] A preferred embodiment of the present invention is an improvement on the '279 patent in that it allows the thin metal plate or metal foil to be embedded just below the surface of the underlayment, concrete in the case of a “poured slab,” so that there is a layer, e.g., concrete, both above and below the thin metal plate or metal foil. That is, a robust “finish” surface, e.g., concrete, is placed above the thin metal plate or metal foil, thus presenting a durable surface of conventional appearance. One advantage of this design is the ability of the surface to resist moisture flow from without while accommodating typical use, e.g., that of hard-wheeled vehicles on a concrete floor that would otherwise damage vinyl or carpet floor coverings.
SUMMARY
[0005] A fluid, or vapor, barrier is encapsulated within a durable structure to preclude passage of fluid in at least one direction while retaining the durability of a surface of a structure that conventionally does not contain such a barrier.
[0006] A first preferred embodiment of the present invention employs a two-part folded thin metal (or composite) plate or metal (or composite) solid (un-perforated) foil such as provided in the '279 patent, but embedded just below the top surface of a durable surface such as an underlayment, typically a concrete “slab” or floor.
[0007] Alternatively, a second preferred embodiment of the present invention employs a two-part thin metal plate or metal foil differing from that of the '279 patent in that the second or top layer of metal is a perforated thin plate or metal foil. The perforations on the top side of the second (top) layer serve to facilitate the formation of a mechanical bond via the concrete oozing through the perforations and acting as a “cementitious rivet” between the top side of the second layer and the bottom side of the surface of the underlayment above this second (top) layer. This mechanical bond acts in addition to any chemical bond formed between the bottom side of the underlayment surface and the remainder of the upper surface of this second (top) perforated layer. This second preferred embodiment must employ a solid thin metal plate or metal foil as a first (bottom) layer to block passage of moisture through the path provided by the underlayment material, typically concrete, that, upon installation, oozed through the perforations in the second (top) layer of perforated thin metal plate or metal foil. That is, if a perforated second (top) layer of a two-part thin metal plate or metal foil is used to achieve a better bond, then the first (bottom) layer must be solid, and conversely, if a perforated first (bottom) layer is used, then the second (top) layer must be solid.
[0008] Alternatively, a third preferred embodiment of the present invention employs a three-part thin metal plate or metal foil differing from that of the '279 patent in that a solid center foil or thin metal plate has an expanded metal foil or thin metal plate, e.g., pleated foil, applied to both sides. Application of the top and bottom pleated foils or thin pleated metal plates may be by way of spot welding in one embodiment. This results in a three-layered system that provides opportunity for the adhesive, e.g., thin-set mortar, to infiltrate slots in the lower foil (or thin metal plate) positioned over the adhesive immediately applied to an existing slab, while the expanded foil (or thin metal plate) attached to the top of this three-layer version establishes a similar mechanical and chemical bond to the overlaid concrete that forms a surface, e.g., concrete flooring. This particular embodiment also aids in resisting “curling” of an overlaid concrete layer that provides a durable surface for use by hard-wheeled vehicles.
[0009] A preferred method of applying a first preferred embodiment of the present invention to an existing porous surface, such as cured concrete, comprises:
applying a layer of adhesive, such as thin set mortar, to the existing surface; placing a folded or pleated thin metal plate or folded or pleated metal foil on the layer of adhesive, e.g., thin set mortar; embedding the bottom of the thin metal plate or metal foil into the adhesive, e.g., thin set mortar; covering the top of the folded or pleated thin metal plate or folded or pleated metal foil with a thin layer of durable material, such as concrete; permitting the adhesive to cure; and finishing and curing the thin layer of durable material, e.g., concrete, as needed.
[0016] Note that if concrete is used as a finish layer, consolidation of this covering concrete must be done with care to avoid loosening the foil bonded to the adhesive, e.g., thin set mortar.
[0017] As an alternative, seams between the pieces (sheets) of the folded or pleated thin metal plate or folded or pleated metal foil may be sealed with flexible commercially available room temperature vulcanizing (RTV) products appropriate for use in alkaline environments. As a further alternative, employing accordion-style pleats at edges of the thin metal plate or metal foil accommodates panel movement while avoiding tearing or breaking the folded thin metal plate or folded metal foil should the installed surface move under load. Of course, this method is not limited to existing installations but may be employed upon initial installation of an underlayment or wall.
[0018] In installing a second preferred embodiment, the above method of installation may be applied using a two-part thin metal plate or metal foil having a first (bottom) layer and a second (top) layer, instead of a single folded thin metal plate or folded metal foil.
[0019] In another method of installing the second preferred embodiment a two-part thin metal plate or two-part metal foil is used in which the second (top) layer incorporates perforations and the first (bottom) layer is solid.
[0020] In yet another method of installing the second preferred embodiment, the immediately above method of installation may be applied using a two-part thin metal plate or two-part metal foil in which the first (bottom) layer incorporates perforations and the second (top) layer is solid.
[0021] Finally, the above method of installation may be applied using the third preferred embodiment, a three-layer sandwich comprising top and bottom layers of perforated, folded or pleated foil or thin metal covering a solid middle layer of foil or thin metal. The top and bottom layers may be joined to the solid center layer by any of a number of suitable processes, e.g., tack welding.
[0022] Embodiments of the present invention are not limited to underlayments but may be used on vertical or slanted surfaces where protection from fluid intrusion is desired. Further, a “one-way” vapor barrier may be installed to prevent intrusion of fluids while permitting expulsion of the same fluids or vapors. Instead of a metal foil or thin metal plate, a special “breathing” polyester such as those marketed under the trademark GORETEX® (waterproof breathable material) may be used in place of metal. This would have particular application in below grade applications such as basement floors or walls and in environments of high humidity such as kitchens or bathroom floors or walls that otherwise “sweat.” In addition to embedding the GORETEX® (waterproof breathable material) lining in concrete on a slab, it could be embedded just beneath a porous outer stucco or similar coating to achieve the same effect as the metal barrier does in the underlayment while also permitting “out gassing” of vapors from within the room.
[0023] Embodiments of the present invention may be used in any application where it is necessary to prevent the movement of fluids (liquid or gas) through porous material, such as concrete. Specifically, it may be used to block the movement of water vapor and will be equally effective in preventing the movement of stable gases, such as radon, through porous material, such as concrete.
[0024] The “embedded barrier” of the present invention, in all of its preferred embodiments, is unique in its implementation. For example, conventionally, a concrete slab has been “sealed” by pre-placing a polymer membrane under the slab prior to placing the new concrete. Once the concrete slab had been installed, the slab could be further sealed only at its top surface. This sealing of the top surface has been accomplished conventionally by using epoxy, fiberglass or combinations of fiberglass and epoxy, leaving a surface that was less durable than a concrete surface.
[0025] To summarize some of the salient advantages of preferred embodiments of the present invention:
it permits modifying existing installations, e.g., addition of concrete above the metal barrier on existing slabs; it allows a trafficked surface above a vapor barrier to be made of durable castable material such as concrete or asphalt concrete; it provides a continuous sheet of metal foil that also serves to reinforce an underlayment, such as a concrete slab; it reduces the opportunity for cracking that occurs on one side of a structure to propagate to the other side; it reduces the opportunity for fractures that exist in the lower part of an underlayment, e.g., a concrete slab, to widen or propagate laterally; in a preferred embodiment it prevents curling of a top surface of concrete that has been applied to an existing concrete slab; and in an alternative embodiment, it accommodates joints between panels of structure, such as an underlayment, by employing a pleated barrier joining section thus permitting movement without compromising the integrity of the barrier.
[0033] Further advantages of the present invention will be apparent from the description below with reference to the accompanying drawings, in which like numbers indicate like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a top view of a single piece thin metal plate or metal foil that may be used in a preferred embodiment of the present invention.
[0035] FIG. 2A is a top view of the perforated piece of a two-piece thin metal plate or metal foil used in a preferred embodiment of the present invention.
[0036] FIG. 2B is a top view of the solid piece of a two-piece thin metal plate or metal foil used in a preferred embodiment of the present invention.
[0037] FIG. 3A is a perspective view of the single piece thin metal plate or metal foil of FIG. 1 as installed in a typical installation.
[0038] FIG. 3B is a perspective view of the two-piece thin metal plate or metal foil of FIGS. 2A and 2B as installed in a typical installation.
[0039] FIG. 4 depicts an alternative installation of a preferred embodiment of the present invention in which an expansion joint is used between flooring panels.
[0040] FIG. 5 depicts an alternative installation of a preferred embodiment of the present invention in which an expansion joint is used between a flooring panel and an adjoining vertical wall.
[0041] FIG. 6A depicts a single layer thin metal plate or foil that has been pleated to be used with a preferred embodiment of the present invention.
[0042] FIG. 6B depicts a three-layer barrier, two of which layers are that configuration shown in FIG. 6A as may be used with a preferred embodiment of the present invention.
[0043] FIG. 7 depicts an alternative means of joining two sections of barrier that may be used in a preferred embodiment of the present invention.
DETAILED DESCRIPTION
[0044] Refer to FIGS. 1, 3A , 3 B, and 6 A. Provided is a method of implementing a fluid barrier within porous material such as concrete. In a preferred embodiment, a barrier panel 100 , in one embodiment including pleats 101 and having pleated edges 102 , is placed between a “base” 311 of porous material, such as a concrete slab, and an emplaced topmost section 313 of durable material, such as concrete, thus creating a topmost surface suitable for use by wheeled traffic. A single layer 600 plate or foil with pleats 101 and related spacings 601 between the pleats 101 may be used as an embedded fluid barrier such as shown at 310 . Also shown at 310 are depictions 315 of the adhesive 312 as it forms in the valleys between pleats 101 and the formation of anchoring portions 314 of the initially “flowable” top layer 313 as it is placed on the surface 103 of a pleated single layer panel 100 of the configuration at 310 .
[0045] Refer to FIGS. 3A, 3B and 7 . Also provided in a preferred embodiment of the present invention is a configuration 310 such as shown in FIG. 3A or the configuration 320 shown in FIG. 3B implementing a barrier to fluid flow in at least one direction and enclosed within porous material. Either configuration 310 , 320 uses a durable top section 313 applied over the barrier panel 100 placed upon adhesive 312 coated on a first section 311 of the porous material. Either configuration 310 , 320 is thus made suitable for routine use by wheeled traffic. Both configurations comprise:
at least one layer of adhesive 312 applied to a top surface of the porous material comprising a base 311 , e.g., thin set mortar applied to a concrete slab; panels 100 of non-porous material having edges 102 suitable for overlapping, e.g., pleated edges, as shown at 701 of FIG. 7 , affixed to a topmost layer of adhesive 312 so as to completely cover the adhesive 312 , a flexible sealant as shown at 702 of FIG. 7 applied between the overlapping edges as shown at 701 of FIG. 7 ; and the topmost section 313 emplaced upon the panels 100 so as to completely cover all said panels 100 , the topmost section 313 incorporating the top surface suitable for routine use by wheeled traffic.
[0050] In a preferred embodiment of the configuration, the barrier is a vapor barrier embedded, i.e., completely enclosed, in porous material. The non-porous material used for the panels 100 may be selected from: a metal, a metal alloy, a steel alloy, a stainless steel, a composite material, a composite material containing at least some metal, and combinations thereof.
[0051] In a preferred embodiment of the configuration, the non-porous material comprises at least one metal and the porous material comprises at least some concrete. Further, the adhesive 312 may be a thin set mortar applied to a thickness of about 6 mm (¼ inch). In a preferred embodiment of the configuration in which the porous material at least partially comprises concrete, the topmost section may comprise concrete applied to a thickness of about 2.5 cm (1 inch) or more.
[0052] Refer to FIG. 7 . In a preferred embodiment of the configuration, a seal 702 comprises a continuous bead of a flexible sealant applied along the entire length between all overlapped edges 701 of the panels 160 . A preferred embodiment of flexible sealant is a RTV sealant.
[0053] Refer to FIGS. 2A, 2B , and 3 B. In a preferred embodiment of the configuration, the panels 100 are plates of a total thickness less than about 6 mm (¼ inch). In an alternate preferred embodiment, the panel 100 comprises a first perforated plate 210 in contact with a second solid plate 220 , i.e., a two-layer panel 100 , each of the first 210 and second 220 plates being of a total thickness of less than about 3 mm (⅛ inch). A preferred configuration places a first perforated plate 210 “layer” immediately adjacent the bottom side of the topmost section 313 , e.g., the finish layer of concrete. A generic two-layer configuration 321 , 322 representing this preferred configuration is shown in FIG. 3B . The first perforated plate 210 would be placed at 321 in FIG. 3B and the second solid plate 220 at 322 in FIG. 3B .
[0054] Refer to FIGS. 2A, 2B , and 3 B. In an alternate preferred embodiment of the configuration, the panels 100 comprise a multi-layer foil of a thickness less than about 2 mm (0.008 inch) and preferably in the range of about 0.5-1.5 mm (20-60 mils), and may be represented as in FIG. 3B as a perforated foil (such as depicted in FIG. 2 at 210 ) at 321 and a solid foil (such as depicted in FIG. 2 at 220 ) at 322 . Each of the foil layers 210 , 220 in a two-layer foil 321 , 322 used in a preferred embodiment of the present invention has a total thickness of less than about 1 mm (0.004 inch) and preferably in the range of about 0.25-0.76 mm (10-30 mils).
[0055] Refer to FIGS. 1, 3A , 6 A and 6 B. In yet another preferred embodiment, the configuration employs panels 100 comprising three-layers, two identical configurations as shown at 600 , and a single flat configuration as shown at 610 . In FIG. 6A , the adhesive 602 is shown as it oozes into the folds of the foil or thin metal from the layers of porous material (not shown separately in FIG. 6A ) above and below the foil or thin metal configuration 600 . In FIG. 6B , by contrast, the adhesive 620 is emplaced to adhere to the portion of the thin foil or thin metal configuration 600 in direct contact with a separate middle layer 610 as described immediately below. These configurations 600 , 610 may be metal (or composite) foil or thin metal (or composite) sheets or plates. The top 600 and bottom 600 layers of the three-layer panel 600 , 610 may be perforated, a solid that is folded or pleated, and combinations thereof, while the middle layer 610 must be solid if both the top and bottom layers 600 are perforated. As foils, the layers 600 , 610 each may be of a thickness less than 1.0 mm (40 mils) and more preferably less than about 0.76 mm (30 mils) and most preferably in a range of thickness from about 0.25-0.76 mm (10-30 mils).
[0056] A preferred method of implementing an embedded barrier comprises:
applying at least one layer 312 of adhesive, such as a thin set mortar, to an entire first surface of the porous material of the base 311 , e.g., a concrete slab, prior to emplacing the topmost section 313 , e.g., a finish layer of concrete; placing panels 100 of non-porous material, such as a metal or composite plate or metal or composite foil, upon a topmost layer 312 of adhesive (if more than one layer of adhesive is used), overlapping edges 102 of each panel 100 with edges of any panels 100 placed adjacent thereto in the same plane along the topmost layer 312 of adhesive such as shown at 701 in FIG. 7 , and completely covering the topmost adhesive layer 312 with the overlapping panels 100 ; establishing a seal 702 as shown in FIG. 7 between all the overlapped panel edges 701 ; and emplacing at least one layer of material comprising a topmost section 313 upon the panels 100 such that each panel 100 is confined below the topmost section 313 and above a topmost layer 312 of adhesive.
[0062] Employing this method, i.e., providing one or more adhesive layers 312 upon a surface of a base 311 of porous material, placing “barrier” panels 100 of one or more layers such as layers depicted at 210 , 220 , 600 , 610 upon the topmost layer 312 of adhesive, establishing a seal 702 between the overlapped edges 701 of the panels 100 and emplacing a topmost section 313 to encapsulate the panels 100 , implements a fluid barrier within porous material, preferably durable porous material such as concrete.
[0063] Refer to FIG. 3A . In one preferred method, the adhesive 312 may then be allowed to “set” or cure prior to installing a finish layer 313 over the plate (or foil) 100 . Not all methods may require curing of the adhesive 312 prior to the finish step, however. The finish layer 313 may be a poured fluid, such as concrete, such that the concrete oozes into the spaces between the channels 101 as shown at 314 , thus facilitating a strong bond between the plate (or foil) 100 and the finish layer 313 . For those underlayments 311 that are exposed to heavy traffic, including hard-wheeled vehicles, for example, the finish layer 313 may be relatively thick concrete. In one preferred embodiment, the result is a multi-layered configuration 310 that achieves an effective moisture and vapor barrier to fluid ingress from beneath the underlayment 311 , while permitting heavy traffic on its concrete finished surface 313 .
[0064] The method of emplacing a fluid barrier within porous material extends to establishing a vapor barrier in porous material. The vapor barrier may be a one-way barrier such that the configuration is permitted to “breathe” or “outgas” in one direction while establishing and maintaining a fluid barrier in the opposite direction.
[0065] In a preferred embodiment of a method of implementation of the present invention, the method employs non-porous material comprising at least one metal and the porous material comprises at least some concrete. Further, the topmost adhesive layer 312 may be a thin set mortar applied to a thickness of about 6 mm (0.25 inch). In a preferred embodiment in which the porous material at least partially comprises concrete, the topmost section may comprise concrete applied to a thickness of about 2.5 cm (1.0 inch) or more.
[0066] Refer to FIGS. 3A, 3B , and 7 . In a preferred embodiment of a method of implementing the present invention, a seal 702 may be established, at least in part, by applying a continuous bead of a flexible sealant along the entire length between all overlapped edges 701 of the panels 100 . A preferred embodiment of flexible sealant is a RTV sealant. In applications where concrete is to be applied as a finishing layer 313 , the RTV sealant should be suitable for use in alkaline environments.
[0067] Refer to FIGS. 1, 2A , 2 B and 3 B. In a preferred method of implementing the present invention, the panels 100 comprise multiple layers 321 , 322 of plates of a total thickness less than about 6 mm (0.25 inch). In an alternate preferred method, the panels 100 comprise a perforated plate 210 as a first layer 321 , the perforated plate 210 having evenly spaced perforations 212 on its interior surface 211 and abutted about its entire surface area to a second solid plate 220 as a second layer 322 , the solid plate having a solid interior surface 221 , and each of the first 210 and second 220 plates being of a total thickness of less than about 3 mm (0.125 inch). A preferred method is to place the first perforated plate 220 immediately adjacent the bottom side of the topmost section 313 as shown at 321 in the configuration 320 of FIG. 3B .
[0068] Refer to FIGS. 2A, 2B , and 3 B. In an alternate preferred method, the method employs panels 100 comprising multi-layer foil of a thickness less than about 4 mm (0.16 inch), and more preferably less than about 2.5 mm (100 mils), and most preferably about 0.5 mm to 1.5 mm (20-60 mils). In yet another alternate preferred method, the panels 100 comprise a first perforated foil 210 as a first layer 321 of a two-layer foil 321 , 322 , the second layer 322 being a solid foil 220 . Each of the first and second foil layers 321 , 322 has a total thickness of less than about 2 mm (80 mils), and more preferably less than about 0.76 mm (30 mils), and most preferably about 0.25 mm to 0.76 mm (10-30 mils). In a preferred embodiment, the first perforated foil 210 is placed immediately adjacent the bottom side of the topmost section 313 as shown at 321 .
[0069] Refer to FIGS. 1, 3A , 6 A and 6 B. In yet another preferred embodiment, the method employs panels 100 comprising three-layers, two identical configurations as shown at 600 , and a single flat configuration as shown at 610 . These may be metal (or composite) foil or thin metal (or composite) sheets or plates. The three layers 600 , 610 are bonded together by any of a number of suitable means, such as by gluing, heating, applying pressure, soldering, tack welding, or combinations of the above. The top 600 and bottom 600 layers of the three-layer panel 600 , 610 may be perforated, a solid that is folded or pleated, and combinations thereof, while the middle layer 610 must be solid if both the top and bottom layers 600 are perforated. As foils, the layers 600 , 610 each may be provided in a thickness less than 1.0 mm (40 mils) and more preferably less than about 0.76 mm (30 mils) and most preferably in a range in thickness from about 0.25-0.76 mm (10-30 mils).
[0070] Refer to FIG. 4 . Some installations 400 of underlayments 311 , such as a concrete slab, applied over a prepared base 404 , such as an aggregate, incorporate embedded expansion joints. A preferred embodiment of the present invention incorporates a sealed expansion joint 401 between each of the overlaid top sections 313 and a corresponding portion of the underlayment 311 . This sealed expansion joint 401 comprises a pleated non-porous strip 402 that is placed over the adhesive 312 at the expansion joint 401 to overlap the entire length of each side of the expansion joint 401 below the installed panels 100 (that may be thin metal or composite plates or foil layers), each overlap of a width less than about 5.0 cm (2.0 inches). The strip 402 is then sealed with an appropriate sealant as shown at 403 along each longitudinal edge of the strip 402 between the top surface of the edge of the strip 402 and the bottom of each panel 100 abutting the expansion joint 401 . A preferred embodiment employs a continuous bead 403 of flexible sealant, such as an RTV, applied along the entire length of the expansion joint 401 .
[0071] Refer to FIGS. 2A, 2B and 3 B. FIG. 2A depicts the perforated piece 210 of a two-piece thin metal plate (or foil) structure shown installed in FIG. 3B at 321 , 322 . The perforations 212 in the main part 211 of this perforated piece 210 facilitate bonding of the metal plate (or foil) structure to either the adhesive layer 312 or the overlaying finish layer 313 as shown in the resultant multi-layered structure 320 of FIG. 3B . The solid piece 220 of the two-piece thin metal plate (or foil) is shown installed as one of the layers in FIG. 3B at 321 , 322 . The configuration 320 of FIG. 3B facilitates additional mechanical bonding of the two-piece plate 321 , 322 , to either the adhesive layer 312 or the finish layer 313 , but not both while providing a solid interface to prevent moisture or vapor flow from beneath the underlayment 311 . A preferred method of installation is to mount the perforated piece 210 against the finish layer 313 and the solid piece 220 against the adhesive layer 312 . In the case of a concrete finish layer 313 , this provides protection for the mechanical bond developed by the concrete as it oozes into the perforations 212 in the perforated piece 210 since no moisture or vapor passes through the solid piece 220 mounted next to the adhesive layer 312 , for example, thin set mortar in the case of a concrete underlayment 311 . Although the perforations 212 are shown as circular holes in FIG. 2A , other means of perforation may be used. For example, the perforated piece 210 may comprise metal screen material very similar to that used in screening windows to prevent insect ingress, a wire mesh, or combinations of types of perforations. Also shown in FIGS. 2A and 2B are alternative edges 102 that facilitate flexion of the installed two-piece plate (or foil) 210 , 220 in much the same manner as described above for the one-piece configuration 100 of FIG. 1 . The two pieces 210 , 220 may be joined together prior to installation by any of a number of means such as application of adhesive to parts of their adjoining surfaces, mechanically pressing edges together, soldering, welding, and combinations of these means. Further, the two pieces 210 , 220 may be installed separately and either joined as would be done in methods described above for joining prior to installation or simply placed one above the other as part of the installation with the weight of the finish layer 313 and the adhesion of the adhesive layer 312 serving to maintain proper alignment. Adjacent two-piece plates (or foils) 210 , 220 may be connected in the same manner as for the one-piece plates (or foils) 100 as described above.
[0072] Refer to FIG. 4 . Expansion joints 401 provide for movement of underlayment 311 in many cases. A preferred embodiment 400 of the present invention provides for bridging these joints 401 while sealing the joint 401 from moisture or vapor and avoiding tearing the underlying metal plate (or foil) 100 , 210 , 220 , 321 , 322 . In a preferred embodiment of the present invention, a separate flexible and expandable “bridge” 402 is provided for bridging expansion joints in underlayments 311 above a sub-grade 404 . This bridge 402 may be a long narrow section of thin metal plate (or foil) similar to that used as the moisture and vapor barrier. The longitudinal edges are flat while the center section is accordion-shaped or pleated to permit movement. These bridges 402 are installed over, and bond to, the adhesive layer 312 at the expansion joint 401 prior to installation of the thin metal plate (or foil) 100 , 210 , 220 , 321 , 322 . The bridges 402 are then bonded to the thin metal plate (or foil) 100 , 210 , 220 , 321 , 322 via any of a number of suitable means such as the application of a continuous bead 403 of a flexible sealant, e.g., any of various commercial RTV sealants suited to the application.
[0073] Refer to FIG. 5 . In much the same way as expansion joints 401 are provided for in underlayments 311 , the joint 501 between a floor and a wall 504 is also subject to movement and a preferred embodiment 500 of the present invention provides for addressing this joint 501 also. The bridge 502 used in this application is affixed at one end to the underlayment in the same manner as for the in-floor expansion joint 401 . The bridge 502 is bent at a right angle to permit installation along the adjoining wall 504 to a point just above the top of the finish layer 313 . A bead 503 of suitable flexible sealant, such as any of a number of commercial RTV sealants, is applied along the entire length of the bridge 502 at the wall 504 .
[0074] The abstract of the disclosure is provided to comply with the rules requiring an abstract that will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. 37 CFR § 1.72(b). Any advantages and benefits described may not apply to all embodiments of the invention.
[0075] While the invention has been described in terms of its preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims. For example, although the system is described in specific examples related to concrete structure, it may be adapted to other porous construction materials, such as drywall, chipboard, wood, tile, composites, and combinations thereof. Thus, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting, and the invention should be defined only in accordance with the following claims and their equivalents. | A barrier to fluid passage is embedded within, instead of atop, porous material to retain the durability of the surface of the porous material. In one embodiment, a thin set mortar is applied to a concrete slab. A pleated metal foil is pressed into the wet mortar and a bond is established. The mortar is allowed to set and a top, or finish, section of concrete is then poured over the foil and finished conventionally. Provisions are made for sealing expansion joints in concrete slab floors and at the juncture of floor and wall. The foil may be provided in multiple layers to provide a mechanical bond via mortar oozing through perforations or along pleats in each of the top and bottoms layers, while providing a solid layer through which a fluid will not pass, at least in one direction. | 4 |
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/EP01/02095 which has an International filing date of Feb. 23, 2001, which designated the United States of America and which claims priority on German Patent Application number EP 00104345.4 filed Mar. 2, 2000, the entire contents of which are hereby incorporated herein by reference.
FIELD OF THE INVENTION
The invention generally relates to a turbine, in particular a gas turbine.
BACKGROUND OF THE INVENTION
In a turbine, in particular in a gas turbine of a turbo set of a power station for energy generation, a hot gas is led through the turbine. A result is that a shaft having moving blades arranged on it is driven. This shaft is connected, as a rule, to a generator for the generation of energy. The moving blades extend radially outward. Stationary guide vanes are arranged in the opposite direction, that is to say radially from the outside inward. As seen in the longitudinal direction of the turbine, the guide vanes and the moving blades engage one into the other in a tooth-like manner.
The turbine, as a rule, has a plurality of turbine stages, a guide vane ring being arranged in each stage. Thus, a plurality of the guide vanes are arranged next to one another in the circumferential direction of the turbine. The individual guide vane rings are arranged successively in the axial direction. The flow path of the hot gas through the turbine is designated hereafter as the gas space.
The guide vanes each include a vane leaf which extends radially into the gas space and is attached to a foot plate, via which the guide vane is fastened to what is known as a guide vane carrier. The individual foot plates of the guide vanes form an essentially closed surface and outwardly delimit the gas space. In order to achieve as small leakage gaps as possible between the individual foot plates, seals are provided, as a rule, between the individual foot plates.
In a conventional seal variant, the foot plate edge region is made thickened, particularly in the case of foot plates adjacent to one another in the circumferential direction, an end-face groove being worked into the thickening. For sealing, a common sealing sheet is introduced into mutually opposite grooves of adjacent foot plates.
The massive construction of the edge region in which the groove for the sealing sheet is arranged presents problems in terms of the thermal load on the foot plate. On account of the high temperatures in the turbine, the foot plates are normally cooled by way of a coolant. In this case, special cooling measures have to be taken for the massive edge region, so as not to give rise to any excessive thermal stresses between the massive edge region and the relatively thin plate region of the foot plate.
This problem is aggravated when a closed cooling circuit, for example a closed steam cooling circuit, is provided for cooling, since this does away with the possibility of guiding through the massive edge region cooling bores through which, for example, cooling air can flow. Instead, in the case of a closed cooling circuit, such bores have to be produced as blind holes, the cooling effect naturally being low in this case, since the cooling medium will scarcely flow through the blind hole to a sufficient extent.
In a further seal variant, the grooves and the sealing sheet are set back from the hot-gas side located on the gas-space side and an undercut is introduced into the massive edge region below the sealing element. Here, too, there is then again the problem of the coolant flowing through this undercut to a sufficient extent. A third seal variant, according to which cooling ducts are introduced into the body of the foot plate itself, is complicated in production terms.
In particular, here, there is the problem that, in order to form the cooling ducts during the casting of the foot plate, a core which is positioned via spacers, also has to be cast in. The core and the spacers are removed by way of suitable measures after casting, so that the cavities formed thereby can be used as cooling ducts. However, there is a connection of the cooling ducts to the outside via the cavity produced by the spacers, so that a closed cooling circuit can be implemented only with difficulty.
SUMMARY OF THE INVENTION
An object on which an embodiment of the invention may be based is, in a turbine, to design the seal between adjacent guide vanes suitably for simple cooling.
An object may be achieved, according to an embodiment of the invention, by a turbine, in particular by a gas turbine, with a gas space and with a number of guide vanes which each have a foot plate and a vane leaf extending radially from the foot plate into the gas space, a sealing element with a reception region, into which the foot plates extend, being provided in each case between the foot plates of adjacent guide vanes.
The fundamental idea of this configuration is to be seen in the reversal of the conventional sealing principle, in which a sealing sheet is introduced into corresponding grooves of the foot plates. To be precise, this necessarily requires a reinforcement of the edge of the foot plates in the groove region, thus ultimately leading to the cooling problems. In this case, in a reversal of this sealing principle, the sealing sheet is not inserted into the foot plates, but, instead, the foot plates are introduced into the sealing element. This avoids the need for a reinforcement of the edge region of the foot plate. Coolability is therefore simplified and the foot plate is cooled homogeneously in all regions, so that no thermal stresses occur.
In a preferred design, the sealing element is designed with an H-shaped cross section with two longitudinal limbs connected via a transverse limb, there being formed between the longitudinal limbs two reception regions which are separated from the transverse limb and into which the foot plates of adjacent guide vanes extend in each case. The sealing element thus partially covers the adjacent foot plates with its two longitudinal limbs, so that, in addition to the sealing property, the foot plates are held by the sealing element.
In view of assembly requirements during the production of the turbine, the sealing element is arranged preferably between guide vanes adjacent to one another in the circumferential direction of the turbine.
According to a preferred refinement, the foot plates each have a side edge bent away from the gas space, in particular radially outward, the sealing element being arranged between two side edges of adjacent guide vanes. The effective sealing height of the seal is thereby increased, without the plate thickness of the foot plate being increased. The two bent-away side edges of the foot plates in this case come to bear, in particular, on the transverse limb of the H-shaped sealing element.
In order to achieve homogeneous cooling and consequently avoid thermal stresses, the side edge has substantially the same material thickness as the remaining foot plate.
In order to prevent the sealing element from projecting into the gas space, the front side of the foot plate, the front side being directed toward the gas space, has, in the region of the sealing element, a bearing surface which is set back from the gas space and on which the sealing element lies. Preferably, at the same time, the sealing element is flush with the foot plate.
In an expedient refinement, there is, for cooling the sealing element, a flow path in the form of a leakage gap for air between the sealing element and the foot plates. There is therefore no desire to have absolute leak-tightness, in order to keep low the thermal load in the region of the sealing element and at the side edges of the foot plate. As a rule, the outside space around the gas space in a turbine is kept at a higher pressure than the gas space, so that air enters the gas space from outside via the leakage gap and the outflow of hot gas from the gas space is avoided.
In a particularly advantageous embodiment, a closed cooling system, through which a coolant is capable of flowing, is arranged in the rear region of the foot plates which faces away from the gas space, that is to say in the outside space. The coolant is in this case, in particular, steam. Alternatively, the coolant used is also a liquid, such as water, or another gas, such as air or hydrogen. Such a closed cooling system allows an effective, directional and homogeneous cooling of the foot plates and of the entire guide vanes.
Preferably, at the same time, the coolant is capable of flowing, in particular directly, over the rear side of the foot plates which faces away from the gas space, so that direct heat exchange takes place between the coolant and the foot plate.
In order to achieve an effective cooling of the foot plates, an inflow duct for the coolant is formed between an outer guide sheet and a baffle sheet, the baffle sheet being arranged between the outer guide sheet and the foot plate and having flow orifices toward the foot plate, and a return-flow duct for the cooling medium being formed between the baffle sheet and the foot plate. A closed cooling system, which has a high cooling action, is consequently implemented in a simple way. During operation, the coolant is supplied via the inflow duct and is guided at high velocity onto the foot plate via the, in particular, nozzle-like flow orifices in the baffle sheet, so that intensive heat exchange takes place between the coolant and the foot plate. The heated coolant is subsequently discharged in the return-flow duct.
Preferably, the baffle sheet is supported on the foot plate via a supporting element, so that the baffle sheet is held at a defined distance from the foot plate.
For simple fastening, preferably the baffle sheet is fastened to the bent-away side edge of the foot plate and the guide sheet is fastened, in particular, to the baffle sheet.
In order to achieve a simple mounting of the foot plates and at the same time good sealing of the foot plates both in the circumferential direction and in the axial direction between adjacent turbine stages, preferably the sealing element described is provided for sealing in the circumferential direction and a further sealing element is provided for sealing in the axial direction. Depending on the direction, therefore, and particularly for assembly reasons, differently designed sealing elements are used.
The further sealing element connects the foot plates to one another in a staple-like manner, preferably on their rear sides facing away from the gas space. The essential advantage is in this case to be seen in the staple-like configuration of the further sealing element which spans the two foot plates. The further sealing element is in this case designed to be elastic, in particular in a plurality of directions, so that, under thermal expansions, it follows the foot plates, without opening up a gap. The sealing by the further sealing element is therefore largely unaffected by thermal expansions.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the invention are explained in more detail below with reference to the drawings, in which, in each case in a highly diagrammatical illustration,
FIG. 1 shows a turbine plant,
FIG. 2 shows the sealing region between two foot plates adjacent to one another in the circumferential direction of the turbine, in a conventional embodiment,
FIG. 3 shows the sealing region in a configuration according to an embodiment of the invention, and
FIG. 4 shows a seal provided, in particular, for foot plates arranged next to one another in the axial direction of the turbine plant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to FIG. 1 a turbine plant 2 , in particular a gas turbine plant of a turbo set for a power station for energy generation, comprises a combustion chamber 4 and a turbine 6 which is arranged downstream of the combustion chamber 4 in the longitudinal or axial direction 8 of the turbine plant 2 . The turbine 6 is illustrated, cut away, in a part region, so that it is possible to look into the gas space 12 of the turbine 6 . The flow path of a hot gas HG through the turbine 6 is designated as the gas space 12 .
During operation, the combustion chamber 4 is supplied via a gas supply 14 with a fuel gas BG which is burnt in the combustion chamber 4 and which forms said hot gas HG. The hot gas HG flows through the turbine 6 and leaves the latter as cold gas KG via a gas discharge line 16 . The hot gas HG is guided in the turbine 6 via guide vanes 18 and moving blades 20 . In this case, a shaft 22 , on which the moving blades 20 are arranged, is driven. The shaft 22 is connected to a generator 24 for the generation of electric energy.
The moving blades 20 extend radially outward from the shaft 22 . The guide vanes 18 have a foot plate 21 and a vane leaf 23 fastened to the latter. The guide vanes 20 are fastened outwardly to the turbine 6 via their foot plate 21 in each case on what is known as a guide vane carrier 26 and extend radially into the gas space 12 . As seen in the longitudinal direction 8 , the guide vanes 18 and the moving blades 20 engage one into the other in a tooth-like manner. A plurality of moving blades 20 and of guide vanes 18 are in each case combined to form a ring, each guide vane ring representing a turbine stage.
In the exemplary embodiment of FIG. 1, the second turbine stage 28 and the third turbine stage 30 are illustrated by way of example.
The foot plates 21 of the individual guide vanes 18 are contiguous to one another both in the axial direction 8 and in the circumferential direction 32 of the turbine 6 and outwardly delimit the gas space 12 .
The foot plates 21 adjacent to one another are sealed relative to one another, in order to keep leakage gaps 34 between them as small as possible.
According to a conventional seal variant for two foot plates 21 arranged next to one another in the circumferential direction 32 , the latter have a thickened edge region 36 , as shown in FIG. 2 . Grooves 40 which are located opposite one another and into which a common sealing sheet 42 is inserted are worked into the end faces 38 of the edge regions 36 of adjacent foot plates 21 . This sealing principle, according to which the foot plates 21 receive a sealing element in the form of a sealing sheet 42 , necessarily requires the reinforced edge region 36 . As a rule, this edge region 36 has a thickness D 1 higher by the factor 3 to the factor 5 than the thickness D 2 of the remaining foot plate 21 .
These different material thicknesses in the edge region 36 and the remaining foot plate 21 lead to problems in terms of a uniform and homogeneous cooling of the foot plates 21 , so that there is a risk of thermal stresses.
In order to avoid this problem, according to the proposed preferred embodiment shown in FIG. 3, the conventional sealing principle is reversed, so that, in this case, the foot plates 21 extend into a sealing element 44 . The sealing element 44 is designed with an H-shaped cross section and has two longitudinal limbs 46 which are connected to one another via a transverse limb 48 .
The sealing element 44 is therefore designed in the manner of a “double-T girder”. Between the two longitudinal limbs 46 are formed two reception regions 50 which are separated from the transverse limb 48 and into which the foot plates 21 extend. Alternatively to the H-shaped design, the sealing element 44 has a T-shaped design, that is to say with only one longitudinal limb 46 . In a sealing element 44 of this kind, the reception spaces formed are open.
In the region of the sealing element 44 , the front sides 52 of the foot plates 21 , the front sides being oriented toward the gas space 12 , each have a bearing surface 54 which is set back from the gas space 12 and on which one longitudinal limb 56 of the sealing element 44 lies. For this purpose, the foot plate 21 has a step-shaped design in the region of the sealing element 44 . The end regions of the foot plates 21 , said end regions adjoining the step, are bent away outward from the gas space 12 approximately perpendicularly and in each case form a bent-away or radially extending side edge 56 . The side edges 56 of the adjacent foot plates 21 directly fit snugly against the transverse limb 48 . An increase in sealing height H is thereby achieved, without the foot plate 21 being reinforced in the sealing region. A flow path 58 designed as a leakage gap is formed between the sealing element 44 and at least one of the foot plates 21 , so that, for example, air from the outside space 60 facing away from the gas space 12 can flow via the flow path 58 into the gas space 12 and therefore cools the sealing region, that is to say the sealing element 44 and the side edges 56 .
To cool the foot plates 21 , in particular, a closed cooling system 62 is provided, which uses preferably steam as a coolant and a detail of which is illustrated in FIG. 3 . This closed cooling system 62 has an inflow duct 64 and a return-flow duct 66 . The inflow duct 64 is formed between an outer guide sheet 68 and a baffle sheet 70 which is arranged between the guide sheet 68 and the foot plate 21 .
The baffle sheet 70 has flow orifices 72 which are designed in the manner of nozzles, so that the coolant supplied via the inflow duct 64 flows over into the return-flow duct 66 along the arrows illustrated. By virtue of the nozzle-like operation of the flow orifices 72 , the coolant is guided at high velocity against the rear side 74 of the foot plate 21 , so that effective heat transmission between the coolant and the foot plate 21 is implemented.
In order to achieve a uniform action of the cooling system 62 , the baffle sheet 70 is supported against the foot plate 21 and kept at a distance from the latter via supporting elements 76 , for example in the form of weld spots or welded webs. The baffle sheet 70 is directly fastened, in particular welded, to the side edge 56 of the foot plate 21 , and the guide sheet 68 is fastened to the baffle sheet 70 .
For assembly and cooling reasons, the sealing arrangement illustrated in FIG. 3 is provided, in particular, for two guide vanes 18 adjacent to one another in the circumferential direction 32 . The illustrated inflow ducts 64 and return-flow ducts 66 therefore extend in the axial direction 8 of the turbine 6 . The foot plates 21 of a guide vane ring are thus sealed relative to one another via the H-shaped sealing element 44 . For assembly reasons, this seal is less suitable, albeit possible in principle, for foot plates 21 of successive turbine stages 28 , 30 , said foot plates being adjacent to one another in the axial direction 8 .
For the sealing of foot plates 21 adjoining one another in the axial direction 8 , according to FIG. 4 a further sealing element 80 is preferably provided, which connects the foot plates 21 to one another in a staple-like manner on their rear sides 74 . The further sealing element 80 is in this case introduced and fastened in grooves 82 which extend essentially radially from the rear side 74 into the foot plates 21 . As illustrated in FIG. 4, the further sealing element 80 is, for example, of U-shaped design with two limbs 86 connected via an arc 84 .
Alternatively to this, the further sealing element 80 is provided with a wavy structure in the manner of a concertina. The elongate U-shaped configuration or else the configuration with the wavy structure has the effect that the further sealing element 80 is elastic and allows all-round movability of the foot plates 21 as a result of thermal expansion. FIG. 4 also illustrates hooking elements 88 which are arranged on the rear sides 74 and by means of which the guide vanes 18 are hooked into the guide vane carrier 26 (cf. FIG. 1 ).
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | A turbine includes a sealing element with a receiving area for sealing the guide blade vanes which are adjacent to each other in the peripheral direction of the turbine. The foot plates of the guide blade vanes extend into the receiving area. The edge area of the foot plates does not have to be reinforced compared to a conventional seal, which enables the entire foot plate to be cooled homogeneously. A closed cooling system can therefore be used for cooling, especially with steam. | 5 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a national stage entry of PCT/Ep2013/003429 filed Nov. 14, 2013, under the International Convention claiming priority over French Patent Application No. 1260893 filed Nov. 16, 2012.
FIELD OF THE INVENTION
[0002] The invention relates to a method for opening/closing an aircraft electric door for a pressurized airframe, together with an electric door intended for implementing this method. This door can be a passenger door, a service door, a cargo door, in nominal or emergency use, or even an emergency exit door.
BACKGROUND OF THE INVENTION
[0003] The opening of an aircraft door can generally be broken down into several phases that succeed each other: unlocking and releasing the safety catch, lifting, pivoting and disengaging the door along the external side of the aircraft fuselage. In particular, triggering the lifting phase can enable the ice that may be present on the external side of the fuselage to be broken before continuing with opening the door through the pivoting and disengaging phases. For closing, the phases take place in the reverse order and according to inverse kinematics.
[0004] In emergency situations, it is necessary to be able to trigger door opening in a single operation. Due to operability constraints on airline personnel, the opening or closing force on the door actuation handle must be limited in normal utilization conditions and in emergency conditions.
[0005] In particular, slight icing of the door (for example, of the order of 2.5 mm thickness of ice on the fuselage) already causes opening difficulties, which does not allow an emergency evacuation of passengers in the safety conditions required in the event of evacuation to be performed. Heavy icing of the door (for example, of more than 6 mm thickness of ice) makes it difficult to open the door, which necessitates the intervention of several operators and causes a delay in disembarking the passengers.
[0006] The doors are therefore advantageously equipped with electric motors that will act to guarantee their opening through an appropriate supply of power. These motors control actuators that guide the door according to pre-established kinematics, with a lifting phase to break the ice on the exterior of the fuselage.
[0007] An aircraft electric door is known from the patent document EP 0 465 785, whose opening and closing kinematics are implemented by a dozen electric motors. These motors are digitally controlled to perform different functioning phases in a coordinated manner: pivoting, closing and locking, as well as the reverse functions.
[0008] The patent document U.S. Pat. No. 5,163,639 furthermore describes an aircraft electric passenger door equipped with two electric motors for controlling the operations: a motor for controlling the rotation of the door and a motor for controlling the means of opening/closing the door.
[0009] The electric door of the patent document EP 1 090 834 is also equipped with two electric motors actuated by a control and management unit. This unit transmits control signals to a first motor to lock/unlock and to lift a door lifting and (un)locking arm, and to a second motor to pivot the door and bring it to its final open position.
[0010] In critical emergency exit situations—fire risk, unsecured landing, serious technical problem—the door must be capable of releasing itself automatically from the fuselage after having actuated the handle. This actuation is generally provided by a pneumatic jack linked with a gas supply.
[0011] These solutions present major drawbacks with regard to safety, especially in cases of emergency opening, and more generally, with regard to the kinematics sequence. These problems are related to the coordination complexity between the motors in performing the different door opening/closing phases, and also to the presence of a pneumatic jack with its gas supply for activation in the event of an emergency. Moreover, breaking the external ice is not the subject of any special treatment in the motorized solutions.
SUMMARY OF THE INVENTION
[0012] The invention aims to remedy these drawbacks of the prior art by integrating the activation of the different phases of releasing the door and harmonizing its movements by means of a single electric motor, including the treatment of the external ice that may be present.
[0013] More precisely, the object of the present invention is a method for opening/closing an aircraft electric door for a pressurized airframe, passenger or service door, being driven by a single electric motor controlled by a door computer:
[0014] for opening the door, after disarming the toboggan, to successively link the sequential phases of unlocking, lifting and pivoting the door by
[0015] unlocking the safety catch of the door by releasing locking means of a locking system;
[0016] electrically lifting the door with a door arm hinged on a vertical hinge mounted on the door, and, driven by the electric motor, with mechanically forced guidance along the vertical axis by preventing a horizontal rotational drive along the same axis;
[0017] releasing a horizontal guideway when the vertical guideway comes against the stop, then pivoting the door arm on a horizontal guideway along a cylindrical surface of a vertical axis of rotation in order to disengage the door along the external aircraft fuselage;
[0018] for closing the door, to rotate the door arm and the door in the reverse direction to that for opening, by horizontal guidance along the cylindrical surface, to stop the horizontal guidance for pivoting the door arm when this guidance comes to the stop, then of lowering the door arm and the door 1 , with mechanically forced guidance along the vertical axis by preventing the rotational drive.
[0019] The door can be opened just as well from the exterior as from the interior of the aircraft, after disarming the toboggan and unlocking the safety catch, by lifting the door with the door arm then by rotating the door arm.
[0020] According to preferred implementations:
[0021] lifting is initiated by an accelerated phase using a lever for multiplying from a few millimeters to about ten millimeters that produces a sufficiently high force to break the ice that may have formed on the aircraft, between the perimeter of the door and the fuselage;
[0022] the door computer manages the movements of the door according to the information transmitted by all of the position sensors fitted opposite the rotating parts equipped with roller bearing Hall effect tracks;
[0023] in the event of an emergency, the unlocking of the door safety catch is triggered in a single operation by actuating an internal handle, which, through detection of its movement, transmits an unlocking signal to the door computer.
[0024] The invention also relates to an aircraft electric door for a pressurized airframe, namely a passenger or service door, comprising a locking system provided with means for locking a safety catch and a system for coordinating door movements having a single electric motor driving a mobile cylindrical support having a vertical rotation axis, managed by a door computer, and a fixed guide, the mobile support and fixed guide being intended to control and coordinate the movement of the door arm. The support has at least one guideway linked with the arm, this guideway being at least partially helical along the vertical axis of the support. The door arm is capable of pivoting around a vertical hinge and is linked with door lifting means mounted between a shaft of the safety catch and the door arm. The fixed guide, likewise cylindrical with a vertical axis, possesses at least one double, vertical and horizontal, camway for guiding the arm successively in these two directions, respectively to prevent it from lifting vertically and then to pivot it.
[0025] According to preferred embodiments:
[0026] at least one lifting slider is associated with a lifting ramp of the door in order to form at least one lever for multiplying the initiating force for lifting the door in order to break the ice that may have formed on the aircraft, between the perimeter of the door and the fuselage;
[0027] a triggering means, internal or external to the aircraft, is capable of actuating the unlocking of the safety catch, this means being chosen between a handle associated with an end of travel detection sensor and a push-button triggering an electrical signal linked with the door computer;
[0028] position sensors are fitted opposite the rotating parts equipped with roller bearing Hall effect tracks and are linked with the door computer in order to transmit position information about these parts;
[0029] in the event of an emergency opening, only the internal handle is capable of directly triggering the unlocking of the safety catch, this triggering being provoked by a signal from a sensor situated at the end of travel of the handle;
[0030] a multiplying lifting lever is placed at each extremity of the safety catch shaft;
[0031] the horizontal camway of the fixed cam is chosen among a groove, a raised edge of a support and a horizontal track, in order to keep the door lifted and to prevent it from lowering;
[0032] the means of locking the safety catch comprise locks mounted on a lock shaft and associated with counter-locks mounted on the safety catch shaft, the locking link between the locks and the counter-locks being released by the triggering means;
[0033] the cylindrical support is a sleeve, rotationally mobile, comprising a camway formed from a helical portion, globally slanting, linked with a guiding slider coming from the door arm; and the sleeve is surrounded by a cylindrical cam support, forming the fixed guide having a double, vertical and horizontal, camway linked with the same guiding slider;
[0034] the mobile cylindrical support is a sleeve rotated by the motor via a vertical column, this sleeve comprising a camway formed from a helical portion, globally slanting, linked with a guiding slider coming from the door arm; and the fixed guide is constituted from a second sleeve coaxial with the first sleeve, forming the double, vertical and horizontal, camway linked with a second guiding slider coming from the door arm via a hinge arm with the motor vertical column passing through it;
[0035] the vertical column is driven by a reducing gear associated with the electric motor;
[0036] the cylindrical support is a screw rod rotated by a back-geared motor via a nut mounted on the rod, this threaded rod forming a helical guideway; and the fixed guide is constituted from a guideway sleeve coaxial with the rod and a hinge plate coming from a fuselage fitting. This sleeve forms a camway, vertical and horizontal, linked with a guiding slider coming from the rod, and the hinge plate forms a horizontal camway linked with another slider coming from the rod;
[0037] the threaded rod is a rod with balls and the nut is a nut with balls.
[0038] In this text, the term “slider” designates both a bearing part such as a roller, rotationally mobile as it moves in a camway or slide, and a non-rotating finger moving in translation in a camway or a slide. The term “motor” or electric motor includes the driving motors used in the field, the motors associated with reducing gears and back-geared motors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Other data, characteristics and advantages of the present invention will emerge on reading the non-limited description that follows, with reference to the attached figures, which show, respectively:
[0040] FIG. 1 , an overall view of the internal side of an aircraft door equipped with an example of a system for coordinating door movements according to the invention, implementing a set of door movement rollers;
[0041] FIG. 2 , a perspective view of the locking system for the safety catch of the preceding example;
[0042] FIGS. 3 a to 3 c , perspective views illustrating the door arm lifting operation in the preceding example;
[0043] FIGS. 4 a to 4 c , side views of the door lifting lever and the safety catch shaft during an initial door lifting phase to break the ice covering the joining perimeter between the external fuselage and the door;
[0044] FIGS. 5 a to 5 c , perspective views ( FIGS. 5 a and 5 b ) illustrating the door arm pivoting operation by horizontal guidance according to the preceding example, and also a partial sectional view showing the installation of the set of rollers ( FIG. 5 c );
[0045] FIGS. 6 a and 6 b , two perspective views along two complementary viewing angles of the door in the closed position, the door being equipped with a second example of a system for coordinating movements with two door movement rollers;
[0046] FIGS. 7 a and 7 b , two perspective views along two complementary viewing angles of the door in the intermediate lifting position, the door being equipped with the second example of a system for coordinating movements;
[0047] FIGS. 8 to 10 , perspective views of the door, respectively in the lifted position, in the intermediate position during its horizontal pivoting rotation, and in the final open position after its horizontal pivoting rotation, the door being equipped with said second example of a system for coordinating movements;
[0048] FIG. 11 , a perspective view of a third example of a system for coordinating movement of an aircraft door having two rollers and a ball rod according to the invention, the door being in the closed position;
[0049] FIGS. 12 a to 12 c , overall and detailed perspective views, and also a vertical sectional view in a plane of symmetry of the third example of a system for coordinating movements, in the initial door closed position;
[0050] FIGS. 13 a and 13 b , and respectively FIGS. 14 a and 14 b , perspective and vertical sectional views in the plane of symmetry of this third example, respectively in the door ready-to-lift position and in the position of door lifted to the upper position, and
[0051] FIGS. 15 a and 15 b , respectively perspective and sectional views in the plane of symmetry of this third example, in rotation around the vertical axis, in order to pivot the door to the open position.
DETAILED DESCRIPTION OF THE INVENTION
[0052] In all of this text, the qualifiers “vertical” and “horizontal” (and their derivatives), relative to the position of items in use, refer to the direction of the Earth's gravity, in relation to land or on water, and to a plane perpendicular to this direction. Furthermore, identical reference characters on the figures refer to the same items with the same functions and the paragraphs that describe them.
[0053] With reference to FIG. 1 , which illustrates an overall view of the internal side 1 a of an example of an aircraft door 1 for passengers according to the invention, a single actuating electric motor 2 is managed by a digital control data processing unit 3 , known by the name “door computer”. An internal locking handle 4 allows a locking system S 4 to be released. A sensor C 1 is placed at the end of travel of the handle 4 in order directly to trigger the starting of the motor 2 in the event of an emergency opening. In normal conditions, this starting is triggered by a dual push-button B 4 of the “on/off” (open/closed) type.
[0054] The electric door likewise comprises a system for coordinating movements 110 , vertical lifting movement and horizontal door pivoting movement. This system 110 comprises the single actuating electric motor 2 , a cylindrical sleeve 50 having a vertical rotation axis Z′Z, intended to be rotated by the motor 2 , and a fixed cam 9 .
[0055] The electric motor 2 is likewise linked with a mobile cam 5 formed in the cylindrical sleeve 50 having the vertical rotation axis Z′Z. This mobile cam 5 is intended to perform the lifting of the door 1 and its pivoting. It has a guideway, called the camway 51 , of a door arm 6 . The arm 6 is hinged on a vertical hinge 61 mounted on the door 1 , in order to pivot the door 1 around the fuselage (see the description referring to FIGS. 5 a and 5 b ). The door arm 6 thus remains free in vertical translation along the axis Z′Z. In particular, during the flight phases, the arm 6 is not loaded by the weight of the door 1 .
[0056] This arm 6 is furthermore linked, in axial rotation along the axis X′X, with a central linking lever 8 , itself linked in axial rotation on a safety catch shaft 43 .
[0057] A fixed cam 9 fitted in a cylindrical sleeve around the sleeve 50 of the mobile cam 5 is likewise intended to guide the door arm 6 in two directions. FIGS. 3 a to 3 c and 5 a to 5 c will more accurately illustrate these guideways in two directions.
[0058] Moreover, a set of guide links 102 is provided on the upper part of the door 1 in order to ensure circular translation when the door opens.
[0059] The perspective view of FIG. 2 is a detailed illustration of the locking system S 4 of the safety catch.
[0060] In this system, a lifting action (arrow F 1 ) through 180 degrees of the internal safety handle 4 (or the actuation of the push-button B 4 of FIG. 1 ) unlocks the safety catch consisting of the tight contact of locks in the form of locking stops 41 of a lock shaft 42 against counter-locks 44 of the safety catch shaft 43 . The shaft 43 is then electrically released from the stop 41 by rotation of the lock shaft 42 , driven by the motor 2 actuated by the door computer 3 (see FIG. 1 ).
[0061] The rotation of the shafts 42 and 43 is detected and electronically monitored by position sensors C 2 and C 3 ( FIG. 1 ), respectively fitted opposite an extremity of the shafts 42 and 43 . These sensors receive a variable induction emitted by Hall effect tracks integrated in the shaft bearings. The sensors C 3 send the angular position of the shafts 42 and 43 to the door computer.
[0062] More generally, the computer manages the movements of the door according to the information transmitted by all of the position sensors fitted opposite the rotating parts, especially—in the illustrated example—opposite the sensors of the shafts 42 and 43 and also that of the motor column (see below).
[0063] This figure also shows the linking lever 8 mounted to rotate axially on a lever roller 81 arranged in a fitting 62 linking with the door arm 6 .
[0064] The lifting operation of the door arm, which starts door opening, is illustrated by the perspective views of FIGS. 3 a to 3 c . In these figures (and also in FIGS. 5 a to 5 c ), the door arm 6 appears as transparent in order to avoid masking the components situated behind.
[0065] The end of unlocking the safety catch, described above, transmits, via the door computer 3 , a command to the electric motor 2 to rotate the mobile cam 5 of vertical axis of rotation Z′Z. To do this, the angular position of the lock shaft 42 is detected, for example by the Hall effect sensors of the lock shaft 42 .
[0066] For this lifting operation, a traveler, presented in the example as a set 63 of coaxial rollers (see FIG. 5 c ) coming from the door arm 6 , is positioned in the helical and globally slanted camway 51 formed on the sleeve 50 . The roller 63 is likewise inscribed in a vertical guideway called the camway 9 v of the fixed cam 9 .
[0067] With reference to FIG. 3 a , in which the safety catch is unlocked but the safety catch shaft 43 remains in the “door closed” position, the roller 63 is simultaneously placed at the low extremity of the slanted camway 51 and the vertical camway 9 v.
[0068] After actuation of the rotation of the cam 5 (arrow F 2 ) by the electric motor 2 and unlocking of the safety catch shaft 43 (see the later passage referring to FIG. 4 b ), the roller 63 rises in the slanted camway 51 of the mobile cam 5 , and also in the vertical camway 9 v of the fixed cam 9 (see FIG. 3 b ). This vertical camway 9 v being fixed, the roller 63 rises vertically in the direction Z′Z and, in this rise, drives the door arm 6 , which therefore likewise rises vertically. The linking lever 8 is then axially rotated by the door arm 6 , and releases the safety catch shaft 43 from its locked position.
[0069] The door arm 6 likewise drives a vertical lifting of the door 1 , and this lifting continues until the roller 63 ( FIG. 3 c ) reaches the upper extremity of the slanted camway 51 and that of the vertical camway 9 v.
[0070] Respectively at the same moments when the views of FIGS. 3 a to 3 c were taken, FIGS. 4 a to 4 c illustrate more accurately, in side views in the frame 100 of the door 1 , the rotation of safety catch levers 4 a placed at the extremities of the safety catch shaft 43 in the aim of unlocking the safety catch shaft 43 . In FIG. 4 a , the shaft 43 is in the locked position relative to safety catch ramps 4 b and to unlocking rollers 40 fitted on the safety catch levers 4 a . The unlocking rollers 40 are released, which at the same time releases the safety catch shaft 43 ( FIG. 4 b ). The rotation of the linking lever 8 then rotates the safety catch levers 4 a . In FIG. 4 c , the door is lifted to the upper position, this lift corresponding to that of the linking fitting 62 .
[0071] During this rotation, lifting rollers 7 a , mounted at the extremity of the safety catch shaft 43 , bear against lifting ramps 7 b , which allows a significant lifting force to develop, in order if necessary to break the ice covering the external skin of the aircraft ( FIGS. 4 b and 4 c ). The moment exerted by the short lever arm formed between the rollers 7 a and the ramps 7 b supplies a large force, which, guided by the lifting ramp 7 b , increases the lifting force: the door is raised by a few millimeters with a force sufficient to break, mainly by shearing, the ice localized between the perimeter of the door and the fuselage.
[0072] With reference to FIGS. 5 a and 5 b , which illustrate the pivoting operation of the door 1 when the door 1 is in the upper position at the end of the lifting operation (as illustrated by FIG. 3 c ), the cam 5 continues to turn (arrow F 2 ). The set of coaxial rollers 63 , which abut the extremity of the slanted camway 51 , is no longer guided by the vertical camway 9 v . Driven by the sleeve 50 , it turns with the latter around the vertical axis Z′Z, while still bearing against a horizontal guideway, called the camway 9 h , of the cam 9 . This rotation causes that of the door arm 6 , pivoting around the hinge 61 of the door 1 (see FIG. 1 ), and therefore causes the door 1 to move forward along the aircraft fuselage.
[0073] The partial sectional view of FIG. 5 c more particularly illustrates the installation of the rollers 63 a and 63 b constituting the set 63 . The rollers 63 a and 63 b are mounted coaxially on a single axle 6 x.
[0074] For door closing, the operations of door pivoting, door lowering, safety catch locking and immobilizing, take place in the reverse order through a control of the motor 2 in inverse rotation and through closing the internal safety handle 4 ( FIG. 1 ).
[0075] A second embodiment of a system for coordinating door movements with two separate rollers is illustrated in FIGS. 6 a to 10 . FIGS. 6 a and 6 b show two complementary perspective views of this system 200 in the door closed position. These complementary views 6 a and 6 b , and also views 7 a and 7 b described below, make it possible to illustrate the relative positions of the rollers.
[0076] In this second embodiment, the camway sleeves are separate: the coordination system 200 comprises a mobile cylindrical sleeve 501 , mounted on the vertical column 20 , which is rotated by the motor 2 via a reducing gear 21 , and a fixed cylindrical sleeve 91 coaxial with the mobile sleeve 501 along the axis Z′Z. The rotation of the column 20 is monitored by a Hall effect sensor C 4 ( FIG. 1 ), as are the lock shaft 42 and the safety catch shaft 43 .
[0077] The mobile sleeve 501 comprises a camway 511 formed from a helical portion, globally slanted on the axis Z′Z, linked with a first door movement guide roller 631 coming from the door arm 6 .
[0078] The fixed sleeve 91 , coaxial with the first sleeve 501 , furthermore forms a double camway 91 h and 91 v , respectively vertical and horizontal, linked with a second door movement guide roller 632 . This second roller 632 comes from the door arm 6 via a lower yoke in which a bore 601 has been made such that the vertical column 20 of the motor can pass through it.
[0079] The complementary perspective views of FIGS. 7 a and 7 b illustrate an intermediate lifting position of the door arm 6 (and therefore of the aircraft door). In FIG. 7 a , the first roller 631 appears to move forward in the slanted camway 511 , this camway rotating around the vertical axis Z′Z. Because the second roller 632 is vertically guided in the camway 91 v ( FIG. 7 b ), the first roller 631 can only move likewise in a vertical movement when it travels the slanted camway 511 .
[0080] With reference to the perspective view of FIG. 8 , the rollers 631 and 632 are at the upper stops of the camways 511 and 91 v . The door arm 6 (and therefore the aircraft door), is then in the upper lifting position.
[0081] As illustrated by the perspective view of FIG. 9 , the first roller 631 is then driven in rotation around the axis Z′Z by the reducing gear 21 via the mobile sleeve 501 . In fact, the second roller is simultaneously guided through the horizontal camway 91 h , which extends as a continuation of the vertical camway 91 v.
[0082] During this rotation, the door arm 6 pivots and FIG. 9 illustrates the arm 6 in the intermediate pivoted position. When the second roller 632 has reached the stop of the horizontal camway 91 h ( FIG. 10 ), the door arm 6 has fully pivoted and the door is fully disengaged along the external skin of the fuselage.
[0083] A third embodiment of the system for coordinating movements of doors with rollers and with ball rods is illustrated in FIGS. 11 to 15 b.
[0084] In the perspective view of FIG. 11 , the system for coordinating movements 300 corresponds to the position of the door arm 6 when the door is closed. This coordination system 300 comprises a vertical rod 23 , forming a threaded rod 502 with balls, and a fixed guideway sleeve 92 coaxial with the rod 23 . The coordination system 300 rests on fittings 330 s and 330 i via cylindrical hinge plates: two upper hinge plates 331 a and 331 b linked with an upper fitting 330 s , an intermediate hinge plate 331 c and a lower hinge plate 331 d linked with a lower fitting 330 i . The sleeve 92 , which is part of the lower fitting 330 i , has the intermediate hinge plate 331 c as its base.
[0085] The rod 23 , intended to be rotated by the back-geared motor 210 , forms a helical guideway 512 linked with a ball nut 633 for lifting the door arm 6 .
[0086] Also illustrated in FIG. 11 are the upper and lower hinge yokes 64 and 65 for rotationally mounting the door arm 6 on the rod 23 , and also an intermediate yoke 66 . These yokes are mounted on guide rings (not illustrated).
[0087] With reference to the perspective and sectional views of FIGS. 12 a to 12 c , which illustrate the door arm 6 in the initial door closed position, the ball nut 633 appears to be mounted around the rod 502 of the rod 23 . The nut and rod with balls assembly forms a rotation system around the rod 23 that is virtually devoid of any friction.
[0088] The fixed sleeve 92 of the intermediate fitting 331 c comprises a vertical camway 92 v ( FIGS. 12 b and 12 c ). This vertical camway 92 v is devoted to a guide roller 634 mounted on a portion 24 a of a transverse rod 24 , consisting of two coaxial portions 24 a and 24 b , and integral with the rod 23 . This transverse rod 24 is made to lift the door arm 6 vertically via the intermediate yoke 66 . Another upper transverse rod 25 , mounted above the intermediate yoke 66 of the door arm 6 , passes through the rod 23 . This upper transverse rod 25 is terminated by two rollers 635 and 636 mounted to turn around this transverse rod 25 .
[0089] After the back-geared motor has been triggered by the push-button B 4 or by the sensor C 1 ( FIG. 1 ), the rod 23 is driven in translation in the direction of lift (arrow F 3 ) along the axis Z′Z, via the ball nut 633 linked with the threaded rod 502 ( FIG. 12 a ). The perspective and sectional views of FIGS. 13 a and 13 b illustrate a position of the rod 23 ready to lift the door arm.
[0090] From the initial door closed position ( FIGS. 12 a to 12 c ) to the position of the rod 23 ready to lift the door ( FIGS. 13 a and 13 b ), the rod 502 is mechanically prevented from rotating by the vertical guidance imposed by the roller 634 moving in the vertical camway 92 v of the fixed sleeve 92 . In the ready-to-lift position ( FIGS. 13 a and 13 b ), the transverse rod 24 has become embedded in the intermediate yoke 66 in order to lift it vertically. The transverse rod 25 lifts with the rod 23 .
[0091] Such a vertical lifting of the door (still according to the arrow F 3 along the axis Z′Z), via the intermediate yoke 66 of the door arm 6 , finishes at the door lifting position called upper. This position is illustrated by the perspective and sectional views of FIGS. 14 a and 14 b . At this stage, the roller 634 has exited the vertical camway 92 v of the fixed sleeve 92 , and coaxially along the vertical axis Z′Z, the upper transverse rod 25 has become embedded in the upper hinge plate 331 b.
[0092] With reference to the perspective and sectional views of FIGS. 15 a and 15 b , the movements coordination system 300 is in the rotation phase for pivoting the arm 6 and opening the door along the external skin of the aircraft fuselage.
[0093] During this phase, the exit of the roller 634 from the vertical camway 92 v ( FIGS. 14 a and 14 b ) releases the rotational drive (arrow F 4 ) of the rod 23 through the nut 633 . Until then, this rotation was mechanically prevented by the vertical camway 92 v . The rollers 635 and 636 then move in a horizontal camway 92 h formed in the upper hinge plate 331 b ( FIG. 15 b ). The vertical translation along the axis Z′Z is then blocked by the hinge plate 331 b . Furthermore, the lower transverse rod 24 is likewise driven in horizontal rotation in a toric groove provided in the intermediate yoke 66 .
[0094] The invention is not limited to the embodiment examples described and illustrated. A battery can therefore be provided to supply electrical energy if the on-board network is no longer capable of supplying electrical current, especially in the event of an emergency. It is moreover possible to provide a substitute manual device to open the door if neither the on-board network nor the battery is capable of supplying electrical current. Such a device is not directly accessible, so that it cannot be deregulated, and is connected directly to the motor or back-geared motor.
[0095] The airborne vehicle is usually an aircraft, but it could be a cargo airplane and, more generally, any flying machine capable of transporting passengers.
[0096] Several parallel camways can furthermore be formed on the sleeves, these camways and the corresponding sliders being vertically aligned in the vertical camway of the fixed cam. | The invention aims to integrate the activation of the opening/closing phases around a single electric motor, including the treatment of the external window that may be present. An airplane electric door according to the invention has a locking system provided with means for locking a safety catch and a system ( 200 ) for coordinating door movements having a single actuating electric motor ( 2 ), a cylindrical support ( 501 ) having a vertical rotation axis (Z′Z), said support ( 501 ) being intended to be rotated by the motor ( 2 ), and a fixed guide ( 91 ). The support ( 501 ) has at least one guideway ( 511 ) connected to the arm ( 6 ), this guideway ( 511 ) being at least partially helical along the vertical axis (Z′Z) of the support ( 501 ). The fixed guide ( 9 ), which is likewise cylindrical with a vertical axis (Z′Z), possesses at least one double, vertical ( 91 v ) and horizontal ( 91 h ), camway for guiding the arm ( 6 ) successively in these two directions in a manner connected to the arm ( 6 ) in order to prevent it from lifting vertically and then to pivot it. | 4 |
This application is a division of application Ser. No. 293,752, filed Aug. 17, 1981, now U.S. Pat. No. 4,406,061.
BACKGROUND OF THE INVENTION
This invention is related to the art of pulping and bleaching lignocellulosic materials to prepare pulps for the manufacture of paper, more specifically to the use of monoperoxysulfates therein.
The use of organic peracids and their salts in a pretreatment step to improve the results obtained from standard alkaline pulping processes and as bleaches for the products of such pulping processes are known.
The present invention concerns the use of monopersulfuric acid and its salts in place of such organic peracids. The use of monopersulfates in such fashion has, to applicant's knowledge, not been previously suggested, nor have they been used in a way which would suggest to a pulp and paper chemist that monopersulfates would perform in pulping and bleaching of lignocellulosic materials in a fashion similar to that of organic peracids, or for that matter, that they may be employed under non-extreme conditions in the treatment of cellulose containing materials to assist in and improve the separation of non-cellulosic materials therefrom.
CITATION OF RELEVANT ART
Applicant is aware of the following references:
U.S. Pat. No. 2,353,823
U.S. Pat. No. 2,388,592
U.S. Pat. No. 2,528,351
U.S. Pat. No. 2,739,034
U.S. Pat. No. 3,351,419
U.S. Pat. No. 3,353,902
U.S. Pat. No. 3,467,574
USSR Pat. No. 604,887, Khim. Drev. (Riga) No. 3, 71-80 (May/June 1978) (Russ.)
Khim Drev. (Riga) No. 9: 109-117 (1971).
SUMMARY OF THE INVENTION
The invention provides a process comprising the treatment of lignocellulosic materials with monoperoxysulfuric acid or its salts with cations.
The tangible embodiments produced by this process aspect of the invention possess the inherent applied use characteristics of being lignocellulosic materials from which the non-cellulosic materials are more readily separated from cellulose thereby indicating usefulness in producing pulp or bleaching pulp for use in papermaking.
The invention also provides in a subgeneric process aspect a process for treating unpulped lignocellulosic material prior to conventional alkaline pulping which comprises treating said unpulped lignocellulosic material with monopersulfuric acid or a salt thereof.
The invention also provides in another subgeneric process aspect a process for bleaching pulp produced by conventional alkaline pulping of lignocellulosic material which comprises treating lignocellulosic pulp produced by said conventional alkaline pulping processes with monopersulfuric acid or a salt thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The manner of practicing the process of the invention will now be specifically illustrated with reference to specific embodiments thereof, namely:
Treatment of northern softwood chips with potassium monoperoxysulfate to prepare chips more readily pulped in alkaline pulping processes and bleaching of nothern hardwood kraft pulp with potassium monoperoxysulfate.
Northern softwood chips may be steeped in a solution containing monopersulfate, conveniently as potassium monopersulfate (KHSO 5 ), conveniently about ten percent by weight KHSO 5 based on the dry weight of wood at a liquor to wood ratio of 7.6 parts by weight liquor to 1.0 parts by weight wood for about 72 hours at ambient temperature, about 20° C. The KHSO 5 is conveniently provided as the mixture 2KHSO 5 .KHSO 4 .K 2 SO 4 , sold under the tradename OXONE by the Dupont Co.
After draining the pretreatment liquor the chips may then be pulped by standard methods, for example, soda or kraft pulping. The pulp so produced will have a lower kappa number, and as a result, lower viscosity and slightly lower yield than pulp produced from identical chips by an otherwise identical pulping process omitting the monopersulfate pretreatment.
Northern hardwood kraft pulp may be treated at about ten percent consistency with persulfate, conveniently provided as OXONE, at about 0.5 percent by weight KHSO 5 based on dry pulp weight for about 3.0 hours at slightly elevated temperature, conveniently about 50° C. followed by extraction with aqueous alkali, conveniently for about 30 minutes with about 0.35 percent by weight sodium hydroxide in water.
The resulting bleached pulp has a lowered permanganate number, substantial brightness improvement and only slightly lowered viscosity.
One skilled in the art will recognize that if additional brightness improvement is desired various known standard bleaching techniques such as ozone, chlorine, chlorine dioxide, and the like may be applied to the monopersulfate bleached pulp.
One skilled in the art will also recognize that in addition to the northern hardwood kraft pulp and the northern softwood chips illustrated, one may apply the persulfate treatment to other known lignocellulosic materials preferably in comminuted form such as chips prior to pulping by standard technique or to the pulps produced from such lignocellulosic materials to obtain analogous results.
While the preferred lignocellulosic species in addition to the northern hardwoods and softwoods illustrated are other woody materials especially tree woods including southern softwoods and hardwoods, other lignocellulosic species commonly employed in making pulp and paper may be employed. Illustrative of these non-woody species are such materials as the grasses, e.g. straw, bamboo, as well as, bagasse, kenaf hemp, jute, and the like.
The exact quantities of monopersulfate as well as the time and temperature of the treatment, when monopersulfate is employed as a pretreatment before pulping, are not particularly critical and may vary within wide limits. Amounts of monopersulfate from about 0.35% to about 35% by weight based on oven dry material may be employed for about 1 to about 72 hours at temperatures from about 20° C. to about 70° C.
Similarly the quantity of monopersulfate when employed as a post pulping bleach may vary widely as may the temperature and time.
Monopersulfate may be employed in amounts equivalent to from about 0.5% to about 5% KHSO 5 , preferably from about 1.0% to about 3.0% by weight based on oven dry pulp for about 0.5 hours to about 3.0 hours at temperatures of from 20° C. to about 80° C., preferably from about 40° C. to 80° C.
The pH employed in either pretreatment or post pulping bleaching may also vary widely. pH values of from about 2.0 to about 12.0 preferably from about 3.0 to about 12.0 may be employed.
The counterion to the HSO 5 -anion is also not particularly critical. In addition to the potassium cation specifically mentioned previously other alkali and alkaline earth metal cations may be employed. Illustrative of these, but not in limitation thereof are the cations of such metals as lithium, sodium, magnesium, cesium, and the like. In addition to cations derived from metals, other non-oxidizable cations, such as, those having the general formula ##STR1## wherein R 1 , R 2 , R 3 , and R 4 may be the same or different and are selected from hydrogen, straight, branched chain or cyclic alkyl of from 1 to about 20 carbon atoms, straight, branched chain or cyclic alkenyl of from 3 to about 20 carbon atoms, straight, branched chain or cyclic alkynyl of from 3 to about 20 carbon atoms, hydroxy alkyl of from 2 to about 20 carbon atoms or any 2 of R 1 , R 2 , R 3 , and R 4 may be concatenated to form, when taken together with the nitrogen atom, a heterocyclic nucleus, such as, pyrolyl, pyridyl, pyrolidinyl, piperidyl, oxazolyl, pyrazolyl, imidazolyl, triazolyl, indolyl, indazolyl, tetrazolyl either unsubstituted or substituted with one or more alkyl, alkenyl, or carbocyclic or heterocyclic aryl moieties; or carbocyclic, or heterocyclic aryl.
Quaternary ammonium cations having at least one straight alkyl chain of at least 16 carbons may be particularly useful in producing softer, less adherent pulp with better hand for tissue and fluff pulp uses.
The substitution of one counter cation for another will be readily accomplished by one of skill in the art employing known standard techniques. Cation exchange employing known cation exchange resins is a particularly convenient method.
In addition to the kraft and soda pulping processes mentioned above, the term standard alkaline pulping processes comprehends all those known pulping processes which are conducted or which are initiated at pH values greater than 7. Illustrative of these processes are such methods as soda-oxygen, neutral sulfite semichemical, alkaline sulfite, polysulfide, bisulfite, alkaline sulfite, and sulfonated chemimechanical.
It will also be obvious to one of skill in the art that the use or the non-use of anthraquinone, anthrahydroquinone, and all related compounds well known in the recent literature in such standard alkaline pulping processes are also both comprehended by the invention.
The following examples further illustrate the best mode contemplated by the inventor for the practice of his invention.
The initial series of examples illustrate the use of monoperoxysulfate in the pretreatment of wood prior to chemical pulping. A series of samples of northern softwood chips having an average moisture content of 15% are treated by immersion in aqueous solutions of OXONE at varying weight concentrations relative to the oven dry weight of the wood at varying times and temperatures.
EXAMPLE 1
Wood chips (425 g) are immersed in liquor containing KHSO 5 (42.5 g) at a liquor to wood ratio of 7.6 to 1.0 at 20° C. for 72 hours. The chips are then drained, washed and soda pulped. Cooking conditions are 22% NaOH, 70 minutes to 170° C., 90 minutes at 170° C. and a liquor to wood ratio of 4 to 1. The resulting pulp has an unscreened Kappa number of 106.5, a screened Kappa number of 92.8, a yield of 51.6% and a viscosity (TAPPI T-230) of 18.2 cp.
From non-pretreated chips when subjected to the same cooking conditions, a pulp is obtained having an unscreened Kappa number of 130.3, a screened Kappa number of 117.3, a yield of 54.8%, and a viscosity of 35 cp.
EXAMPLE 2
Following a procedure analogous to that of Example 1 from 425 gms. of wood chips pretreated with 127.5 g KHSO 5 and pulped under similar conditions, a pulp is obtained having an unscreened Kappa number of 55.16 a screened Kappa number of 46.2, a yield of 45.8% and a viscosity of 18.8 cp.
EXAMPLE 3
Following a procedure analogous to that of Example 1 from 425 g of wood chips pretreated at 50° for 24 hours with 127.5 g KHSO 4 and pulped under similar conditions, a pulp is obtained having an unscreened Kappa number of 73.1, a screened Kappa number of 50.5 and a yield of 51.4%.
EXAMPLE 4
Following a pretreatment procedure analogous to that of Example 1 from 425 g of wood chips pretreated with 42.5 g KHSO 5 then subjected to kraft cooking at 14% active alkali, 20.6% sulfidity, 4:1 liquor to wood ratio, 70 minutes to 170° C., 80 minutes at 170° C., a pulp is obtained having an unscreened Kappa number of 74.7 and a yield of 51.4%.
From a similar pulp cooked under similar kraft conditions but not pretreated, a pulp is obtained having an unscreened Kappa number of 98.1 and a yield of 52.4%.
EXAMPLE 5
Following a procedure analogous to that of Example 4 from 425 g of wood chips pretreated with 85 g of KHSO 5 and then cooked under similar kraft conditions, a pulp is obtained having an unscreened Kappa number of 51.8 and a yield of 48.3%.
EXAMPLE 6
Following a procedure analogous to that of Example 4 from 425 g of wood chips pretreated with 127.5% KHSO 5 then pulped under similar kraft conditions, a pulp is obtained having an unscreened Kappa number of 23.7 and a yield of 43.1%.
EXAMPLE 7
Following a pretreatment procedure analogous to that of Examples 1 and 4, there is obtained from 425 g of wood chips pretreated with 42.5 g KHSO 5 and then kraft pulped at 18% active alkali, 20.6% sulfidity, 4 to 1 liquor to wood ratio, 90 minutes to 170° C. and 90 minutes at 170° C. a pulp having an unscreened Kappa number of 33.1 and a yield of 42.8%. From a similar pulp cooked under analogous conditions but not pretreated, a pulp is obtained having an unscreened Kappa number of 37.2 and a yield of 43.1%.
The following examples illustrate the use of monopersulfate in bleaching of pulp. A northern hardwood kraft pulp having an initial permanganate number (P-number) of 8.4, 25.8% brightness (G. E.) and a viscosity of 22.6 cp. is treated with OXONE at ten percent consistency at 50° C. for three hours. Twenty-five oven dried grams of pulp are used in each example. Following completion of the OXONE treatment all pulps are extracted with aqueous NaOH (0.35%) prior to determination of P-number, brightness and viscosity.
EXAMPLE 8
Pulp is treated with KHSO 5 (0.5 weight percent based on oven dry pulp) at pH 3.0 (adjusted with H 2 SO 4 ). The pulp obtained has P-number 6.85, brightness 29.95%, viscosity 22.17 cp.
EXAMPLE 9
Following a procedure analogous to that of Example 8 except that pH of bleaching is 11.0 (adjusted by NaOH) there is obtained a pulp having P-number 6.5, brightness 30.35, viscosity 21.93 cp.
EXAMPLE 10
Following a procedure analogous to that of Example 8 except increasing the amount of KHSO 5 to 3.0 weight percent based on oven dried pulp, there is obtained a pulp having P-number 5.3, brightness 34.4%, viscosity 18.9 cp.
EXAMPLE 11
Following a procedure analogous to that of Example 9 except that the amount of KHSO 5 is increased to 3.0 weight percent based on oven dry pulp, there is obtained a pulp having P-number 5.25, brightness 35.7% and viscosity 19.4 cp. | Treatment of lignocellulosic materials with monoperoxysulfate to permit more ready separation of non-cellulosic materials therefrom to produce papermaking pulps is disclosed. | 3 |
FIELD OF THE INVENTION
The present invention relates to a novel class of oncogenes. In particular, a novel oncogene, mutant TC21 has been associated with human ovarian carcinoma cells. Mutations of R-ras have also been found to be oncogenic. The novel oncogenes of the present invention are useful in detecting transformed cells in tumors and tissues not previously associated with an activated oncogene.
BACKGROUND OF THE INVENTION
A family of small G-proteins encoded by H-, K-, and N-ras is frequently activated as oncogenes in a wide array of human tumors (Bos, 1989). Activation is generally due to point mutation at one of two major sites, position 12 or 61, within the coding sequence. These mutations cause the molecule to be constitutively in the GTP bound (active) rather than GDP bound (inactive) state (Barbacid, 1989). In normal cells, these proteins are coupled to growth factor signaling pathways and appear to cause proliferation or differentiation depending on the cell type (Chardin, 1991). Over the past several years, cloning efforts by many laboratories have greatly expanded the number of known ras-related proteins, some of which like Rho and Rac, are coupled to signaling pathways related to cell motility (Ridley & Hall, 1992; Ridley et al., 1992). Others, including the Rab proteins are involved in intracellular vesicular transport (Novick & Brennwald, 1993).
Three ras-related molecules, R-ras, K-rev-1/rap and TC21, within the ras superfamily are more closely related to ras than to either Rho or Rab subfamilies. TC21 has recently been cloned by means of degenerate PCR primers but is otherwise uncharacterized (Drivas, et al., 1990). The human R-ras gene was initially cloned by low-stringency hybridization method using a viral H-ras cDNA as probe (Lowe et al., 1987). R-ras has been thought to be non-transforming since efforts to detect transforming potential by introduction of ras-activating mutations were unsuccessful (Lowe & Goeddel, 1987). Recent studies have demonstrated R-ras interacts with the BCL-2 product involved in a signaling pathway that intervenes with apoptosis (Fernandez-Sarabia & Bischoff, 1993). K-rev-1/rap, was initially detected as a suppressor of ras transforming function (Kitayama et al., 1989).
Three previously identified ras genes with transforming potential include H-, K- and N-ras. Whereas H-, K- and N-ras p21 proteins share 75% amino acid sequence identity, this similarity increases to greater than >97% when their putative N-terminal catalytic domains (positions 5 to 120) are compared. In contrast, TC21 shows 56% overall similarity and only 70% relatedness in the conserved catalytic domain. Structurally, TC21 also contains an N-terminal 11 amino acid extension, which would result in a predicted 23 kD product rather than the 21 kd proteins observed for H-, K- as well as N-ras. Of note, TC21 is more closely related to H-, K- and N-ras than the human R-ras gene product with 64% identity throughout, and 76% similarity in the most conserved domain. R-ras was initially identified by low stringency hybridization using a viral H-ras probe (Lowe, et al., 1987). Yet, efforts to mutationally activate R-ras as an oncogene in vitro were unsuccessful (Lowe & Goeddel, 1987). Thus, it would not be possible to predict the oncogenic potential of TC21 by comparison of its overall similarity or function with known ras-related genes.
Previously identified ras oncogenes have been implicated in a wide array of human malignancies. Greater than 90% of pancreatic carcinomas and more than 50% of colon carcinomas exhibit activating mutations of H- or K-ras alleles (Bos, 1989). Such oncogenes have also been identified in a variety of other carcinomas. In contrast, N-ras oncogenes seem to be preferentially observed in mesenchymal and hematopoietic malignancies (Bos, 1989). Evidence from experimental models indicates that ras oncogenes may be responsible for initiation of the malignant process as well as play important roles in later steps of tumor progression of cancers in which an activated ras protein has been identified to exist (Barbacid, 1987). Oncogenes have yet to be commonly detected in many human tumors. These include ovarian, breast and prostate tumors as well as hepatomas and melanomas.
SUMMARY OF THE INVENTION
As an approach to identify new human oncogenes, the present invention has generated an expression cDNA library from an ovarian carcinoma line. The present invention relates to the detection of a potent transforming gene product. The transforming gene product was identified as mutant TC21 protein, having a single point mutation substituting glutamine with leucine at position 72. TC21 is a recently cloned member of the ras gene superfamily. While the mutant TC21 cDNA clone possessed high transforming activity, the ovarian tumor genomic DNA which contained the mutated TC21 allele failed to induce transformed foci. Thus, by the use of a non-conventional expression cDNA cloning system, it was possible to identify and isolate a new human oncogene that has evaded detection by cloning techniques within in the art.
Based on the finding that an oncogenic form of TC21 exists, the present invention also relates to the generation of various point mutations to a close relative, R-ras, for expression study in rodent fibroblasts. Mutations introduced to the R-ras gene at positions 38 and 87 induced morphological transformation in NIH/3T3 cells at high frequency. NIH/3T3 cells transfected with mutant R-ras plasmids grew well in soft agar and were tumorigenic in animals. The 4.6 and 1.2 kb transcripts of R-ras were ubiquitously expressed in all human tissues examined. The present invention provides further biological evidence that R-ras gene can indeed synergize with c-raf-1 gene in inducing cellular transformation. In fact, cooperation between wild-type H-ras and c-raf-1 genes in transforming NIH/3T3 cells has previously been reported (Cuadrado et al., 1993). In the instant invention, the use of wild-type R-ras gene was insufficient to register a cooperative effect and expression of the oncogenic R-ras mutant at position 38 ("R-ras val38 ") construct was necessary to produce a similar result in activating the transforming pathway in NIH/3T3 cells.
Based upon the finding that the proteins of the present invention are oncogenic, mutations clustered within these regions also exhibit oncogenic characteristics. For TC21, mutations clustered around codon positions 23 to 75 will result in a mutant having oncogenic properties. For R-ras, mutations clustered around codon positions 3 to 87 will have oncogenic activity. Analogous regions of other ras proteins have been demonstrated to produce oncogenically active mutants of ras (Bos, 1989).
The present invention relates to methods of diagnosing cancers and cell transformations by detection of mutant forms of R-ras or TC21 or detection of mutant forms of the corresponding genes. The novel oncogenes of the present invention are important in serving as tumor markers, allowing relevant cancers to be diagnosed and monitored in prognosis of disease progression. The invention further relates to detecting mutant TC21 or the mutant TC21 gene in ovarian tissue to determine whether said tissue is transformed. The present invention also relates to a kit for diagnosing certain types of cancers by determination of elevated levels of mutant TC21 and/or R-ras, or by expression of mutant forms of the corresponding genes.
The present invention also relates to methods of controlling or inhibiting the transforming capability of the novel oncogenes of the present invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1. Transformed focus induced by rescued plasmid 66-1. Approximately 1.5×10 5 NIH/3T3 cells were transfected with 0.01 mg of plasmid DNA. The morphology of a typical focus after two weeks in culture is shown.
FIGS. 2A, 2B & 2C. Physical characterization of transforming cDNAs. (2A) Schematic representation of the 1.7 kb and 2.4 kb cDNA inserts of 64-1 and 66-1 plasmids, respectively. Open reading frames encoding the TC21 gene product are indicated by filled boxes and 5' and 3' untranslated regions are represented by open boxes. Abbreviations of restriction enzymes are: S (SalI), B (BglII), H (HindIII) and, X (XbaI). (2B) Sequence disparities in N-terminal coding regions of the TC21 (Drivas, et al., 1990) and 66-1 cDNAs. Nucleotides at positions 11, 20, and 33 in 66-1 not present in TC21 are shown, and the resulting changes in amino acid sequence are indicated. (2C) Sequence analysis flanking nucleotide position 215 showing the wild-type and mutant TC21 sequences. The adenine (hereinafter called "A") to thymine (hereinafter called "T") transversion in the second base pair of codon 72 of the TC21 oncogene is boxed.
FIGS. 3A & 3B. Detection of TC21 mutation in A2780 human ovarian carcinoma cells. (3A) Schematic representation of the strategy for detection of mutations at position 215 by PCR showing primers a and b (arrows) used for amplification of the region between positions 168 to 312. The polymorphic BfaI site generated as a result of the A to T transversion at position 215 is indicated by an asterisk. An additional BfaI site at position 191, which serves as an internal control for restriction enzyme digestion, is also shown. The shaded bar represents the 45 bp oligonucleotide probe, tc26, used for detection of mutant-specific restriction fragments. (3B) Southern analysis of Bfal digested PCR fragments generated from RNA samples derived from AB589 human mammary epithelial cells, A2780 ovarian carcinoma cells at early (E), medium (M), and late (L) passages, and the SK-ES-1 human Ewing's sarcoma cell line (Nishida & Gotoh, 1993). Samples were subjected to Southern blot analysis and hybridized with the tc26 probe. The 95 bp mutant-specific fragment, the 143 bp band representing uncut DNA, and the 119 bp band representing the wild-type specific fragment obtained by digestion at position 191 alone, are indicated.
FIGS. 4A & 4B. TC21 expression of in cell lines and tissues. (4A) Northern analysis of total cellular RNA obtained from a AB589 human mammary epithelial cells, early, medium, and late passages of A2780 cells (A2780E, A2780M, A2780L), and NIH/3T3 cells transfected with the TC21 transforming plasmid (NIH3T3/TC21) or with control plasmid, pSV2neo (NIH3T3/neo). Approximately 20 mg of total cellular RNA was subjected to Northern blot analysis using a 32P!-labeled TC21 cDNA probe. A major 2.5 kb and a minor 1.7 kb TC21 transcript are indicated. Equal amounts of RNA were loaded in each lane as confirmed by ethidium bromide staining. (4B) Expression of TC21 gene in tissues was analyzed utilizing a commercially available filter (Clontech, Palo Alto) with approximately 2 mg of poly(A)+ RNA loaded in each lane. Following hybridization with a TC21 cDNA probe, the filter was stripped and rehybridized with a control mouse β-actin probe for normalization of the amount of RNA loaded.
FIG. 5. In vitro transcription/translation of R-ras mutant plasmids. Samples with 1 mg of circular plasmid DNAs from wild-type (R-ras wt ), position 38 (R-ras val38 ) and position 87 (R-ras leu87 ) mutants of R-ras gene were in vitro transcribed and translated with rabbit reticulocyte lysate in the presence of 35S!methionine. Controlled reactions were performed with either no DNA added (-) or with a Ga12 plasmid that has previously been described (Chan et al., 1993). The 23-kDa and 44-kDa protein species encoded by R-ras and Ga12 cDNAs, respectively, are indicated by arrows.
FIG. 6. Focus morphology of NIH/3T3 transfectants. Expression plasmids representing R-ras wt , R-ras val38 , and R-ras leu87 constructions were transfected separately into NIH/3T3 cells, and morphologically transformed foci were photographed after 2 weeks in culture.
FIGS. 7A & 7B. Expression of R-ras. (7A) Cell lysates derived from NIH/3T3 cells transfected with various expression plasmids were analyzed by Western blotting techniques. Approximately 100 mg of total cell protein was loaded per lane and immunoblotted with a pan-ras monoclonal antibodies, M90. The 23-kDa protein species of R-ras are indicated by an arrow. (7B) Tissue distribution of R-ras transcripts was examined utilizing a commercially available nitrocellulose filter (Clontech) with about 2 mg of poly(A)+RNAs derived from various human tissues. 32P!-labeled R-ras cDNA probe was hybridized to the filter and the amount of RNA loaded was normalized with a mouse β-actin probe. The 4.6- and 1.2-kb transcripts of R-ras are indicated.
FIG. 8. Tumorigenicity of R-ras mutants. ˜1.0×10 5 cells were introduced subcutaneously into athymic nude mice. 7 mice were used for tumorigenicity assay for each transfectant. Data indicates incidence of tumors at the week after inoculation.
DETAILED DESCRIPTION OF THE INVENTION
The present invention utilizes an unusual and efficient cloning vector system which allows stable cDNA expression (Miki, et al., 1991). This system combines the ability to generate high complexity phagemid libraries containing a large proportion of full length cDNAs with the ability to perform efficient rescue of integrated plasmids (Miki, et al., 1989). In order to uncover novel human oncogenes by this strategy, an expression library was generated from an ovarian carcinoma line. The ovarian carcinoma cell line is a tumor type in which oncogenes were previously for the most part uncharacterized.
The present invention demonstrates the application of a stable expression cDNA cloning strategy in isolating new human oncogenes. One embodiment of the present invention is a novel oncogene, a mutated allele of TC21, which is a member of the ras superfamily. The TC21 oncogene of the present invention contains a position 72 substitution, resulting in the reduction of the intrinsic GTPase activity of the molecule. Other mutations clustered within this region will result in similar oncogenic activation. The TC21 oncogene is shown to activate oncogenic properties in tissue culture and in vivo, and to be present in the initially established human ovarian carcinoma line. Thus, the mutated TC21 allele of the present invention is likely activated as part of the malignant process in this tumor.
A striking finding was the lack of TC21 oncogene detection by standard NIH/3T3 transfection analysis using A2780 ovarian tumor cell line DNA. Such a standard transfection analysis incorporates genomic DNA fragments into the host cells. TC21 downstream signaling pathways in NIH/3T3 cells must be intact, because this oncogene was almost as efficient in transformation as an H-ras oncogene under analogous LTR transcriptional control. The TC21 oncogene including essential regulatory elements may be too large to allow efficient genomic transfer. Alternatively, species or tissue specific differences in transcriptional regulation of the genomic TC21 sequence may prevent a sufficient level of its expression for induction of the transformed phenotype.
The present discovery of new human oncogenes of the ras superfamily, which have evaded detection by previous approaches, raises the possibility that this oncogene may be widely implicated in human malignancies. The present finding that mutated TC21 exists in an ovarian cell line is significant, since this tumor-type has previously not been correlated with an activated ras-oncogene.
Two previous reports have examined the transforming capability of R-ras. These researchers attempted mutation of R-ras within the region of R-ras thought to inhibit GTPase activity. However, these experiments did not lead to the conversion of R-ras into a transforming factor. The inability of two previous reports to show both transforming (Lowe & Goeddel, 1987) or growth promoting (Rey et al., 1994) is contrary to the present invention, in which both position 38 and 87 mutants can efficiently induce morphological and malignant transformation in rodent fibroblasts. This disparity can be explained by potential experimental variations due to the use of different expression vectors of the higher susceptibility of NIH/3T3 cells to undergo transformation when compared to the Rat 1A cells used in the early study. These different results illustrate the unexpected nature of the present invention.
R-ras like TC21, is evolutionarily distant to H-ras, K-, or N-ras. But all of these proteins share a highly conserved N-terminal catalytic domain with effector binding sequences (amino acid sequence 32-40 in H-ras) (Valencia et al, 1991). Of all the small GTP-binding proteins with transforming activity in rodent fibroblasts, there exists a hierarchy of transforming ability with mutant H-ras gene displaying the highest potency of transforming properties. The second most potent transforming factor was the position 72 mutant of TC21 and yet weaker as a transforming factor were the two mutants of R-ras. This gradation of transforming potential is correlated with the efficiency and morphological parameters associated with cellular transformation. These marked differences among small G-proteins may reflect their relative ability in inducing downstream signaling cascade leading to cellular transformation.
The fact that the position 87 mutation of R-ras was stronger than the position 38 mutation in inducing transformation is also an unexpected result. In the case of H-ras, glycine 12 (gly38 in R-ras) is situated in the phosphate-binding domain and Mg2+ binding site in the first half of the guanine nucleotide binding domain and glutamine 61 (gln87 in R-ras) was postulated to be involved in interacting with a water molecule believed to attack the γ-phosphate (Valencia et al., 1991). Mutations in both positions of the ras oncogenes have been shown to abolish their GTPase activity leading to a GTP-bound, constitutively active state. The oncogenicity of both R-ras mutants analyzed in this study is most likely due to their GTPase deficiency, however, we do not exclude the possibility of impaired interaction with regulator molecules such as GTPase-activating proteins (GAP), guanine-nucleotide exchange stimulators or downstream effector elements such Raf (Boguski & McCormick, 1993).
The present finding that mutant TC21 and mutant R-ras can be oncogenic, in combination with the knowledge that particular sites within ras genes, when mutated are highly oncogenic ("hot spots") (Bos, 1989), leads to the conclusion that analogous mutations within hot spots of TC21 and R-ras will be oncogenic. Within TC21, mutations clustered around codon positions 23 to 75 are expected to have oncogenic properties. While within R-ras, mutations clustered around codon positions 38 to 87 are expected to have oncogenic properties. These mutational hot spots could not have been predicted prior to the present invention, since there was no suggestion that mutants of R-ras or TC21 would be oncogenic.
It has been reported that the C-terminal 60 amino acid region of the R-ras encoded product interacts with the Bcl-2 oncogene product both in vitro and in vivo (Fernandez-Sarabia & Bischoff, 1993). It was speculated that R-ras gene product may be involved in mediating the process of programmed cell-death and that Bcl-2 blocks this pathway. The present invention, in contradistinction, provides strong evidence that R-ras gene product when in the activated state can, in fact, efficiently promote cell growth and transformation. Whether R-ras plays a role in providing signals for cell survival remains to be determined.
The prevalent view of human carcinogenesis postulates a multi-step process involving the activation of cellular proto-oncogenes and inactivation of tumor suppressor genes (Weinberg, 1991). Tumor suppressor genes, such as, p53 and more recently, p16, have been implicated in more than 50% of all human cancer (Kamb et al., 1994). In contrast, oncogenes have yet to be commonly detected in many human tumors. These include ovarian, breast and prostate tumors as well as melanomas. Previously identified ras oncogenes have been implicated in a wide array of human malignancies (Bos, 1989). Greater than 90% of pancreatic carcinomas and more than 50% of colon carcinomas exhibit activating mutations of Hor K-ras alleles. In contrast, N-ras oncogenes seem to be preferentially observed in mesenchymal and hematopoietic malignancies. The novel oncogenes of the present invention provide two more additional targets for mutational activation. The wide spectrum of tissue expression of the R-ras transcripts provides strong impetus for identifying R-ras mutations in diverse human tumor types.
The presence of specific marker genes has important implications with respect to diagnosis and prognosis (Muss, et al., 1994). The oncogenes of the present invention provide a marker for identifying and diagnosing the transformation of cell populations in human tissues. These marker genes can serve as a prognostic marker in determining initial cell transformation, severity of tumors, tumor-progression and tumor relapse.
The mutant R-ras and TC21 can be detected either at the protein level or the gene itself can be analyzed for diagnosis and prognosis. At the protein level, mutant R-ras or TC21 can be detected in cell populations by monitoring protein expression levels in cases where oncogenesis is concomitantly associated with overexpression of ras. Alternatively, mutant R-ras and mutant TC21 can be detected using immunoblotting or in situ immunostaining techniques.
In one embodiment, the mutant TC21 and/or R-ras can be detected by a mutant-specific monoclonal or polyclonal antibody (Stiles et al.; Kohler and Milstein, 1975). Production of such antibodies are within the skill in the art, in view of the present invention and are thus considered within the scope of the invention. A standard immunoassay can be used to detect mutant TC21 and mutant R-ras.
Another embodiment for detecting mutant R-ras and mutant TC21 protein in tumors or tissue samples utilizes an altered mobility assay (Srivastava, et al., 1985). This assay can be used to distinguish mutant ras proteins from wild-type based on an altered mobility through gel electrophoresis.
Yet another embodiment for diagnosing or prognosing cancers having an oncogenic R-ras or TC21 utilizes the gene itself. The mutant gene can be detected in tissue samples as well as in situ using a nucleic acid probe specific for the mutant form of R-ras and/or TC21.
Another embodiment for detecting mutant R-ras or mutant TC21 nucleic acid in tumors or tissue samples utilizes an RNase protection assay (Bos, 1989). This assay could be useful in distinguishing R-ras and TC21 mutants from wild-type ras by use of a nucleic acid probe spanning the mutated region within the gene. Upon treatment of the probe-RNA hybrid with RNase, the form containing the mis-match will be cleaved, thereby producing two fragments when analyzed by gel electrophoresis.
Mutant TC21 can be used as a marker gene for diagnosis of cell transformation in ovarian tissue. Mutant TC21 gene can be detected in ovarian tissue samples by single strand conformational polymorphism (Orita, et al., 1989a; Orita, et al., 1989b) R-ras genes can also be detected by SSCP.
In addition, the present invention identifies new cancers which are associated with novel oncogenic ras-related gene, so that inhibition of such cancers is now possible. Such treatments utilize specific inhibitors of ras, which mechanistically function in a variety of ways. One method of blocking oncogenic ras activity involves blocking the functional group of ras required for its association with the cell membrane. The cell membrane is the site where ras is thought to facilitate its signal transduction activity. Ras normally is myristylated. Blocking myristylation results in a ras protein incapable of making the necessary association with the cell wall to be functional. However, much like other conventional chemotherapeutics, such therapeutic treatment may have an adverse effect on normal cells.
EXAMPLES
The following methods were used in carrying out the experiments illustrative of the present invention. These experiments represent non-limiting examples of the present invention. Other embodiments would be readily apparent to the skilled artisan and are considered within the scope of the present invention.
Library Construction
A cDNA expression library was constructed as described in Miki, et al., 1989, from poly(A)+ RNA generously provided by Dr. G. Kruh, Fox Chase Cancer Center. cDNAs were inserted directionally into the λpCEV29 eukaryotic expression vector, which is a derivative of the λpCEV27 vector (Miki, et al., 1991). The λpCEV29 plasmid is essentially the same as λpCEV27, except that a pak1 restriction endonuclease site has been added for ease of plasmid rescue. For the purposes of the example experiments the two plasmids, λpCEV27 and λpCEV29 are interchangeable.
The λpCEV27 system was developed to clone cDNAs by means of stable phenotypic changes induced by a specific cDNA. Use of a λ-plasmid composite vector made it possible to generate high complexity cDNA libraries and to efficiently excise the plasmid from the stably integrated phagemid DNA. This phagemid vector contained several features including two SfiI sites for construction of cDNA libraries using the automatic directional cloning (ADC) method, an M-MLV LTR promoter suitable for cDNA expression in mammalian cells, the SV40 promoter-driven neo gene as a selectable marker, and multiple excision sites (MESS) for plasmid rescue from genomic DNA. The λpCEV27 system incorporated, in addition to the M-MTV LTR, the rat preproinsulin polyadenylation (polyA) signal downstream from the cDNA cloning site. In this vector, the bacterial neo gene was placed under the independent control of the SV40 early promoter and the SV40 late polyA signal for use in marker selection in mammalian cells. The bona fide promoter of the neo gene was removed so as to fuse the SV40 promoter directly to the neo structural gene.
The cDNA library consisting of ˜10 7 individual phage clones was amplified by a standard plate lysate method for DNA transfection experiments. Focus identification and plasmid rescue procedures were performed as described (Miki, et al., 1991).
Cell Cultures
Cultures were maintained in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% calf serum (CS). NIH3T3 cells carrying different plasmid constructs were derived by transfecting 1.5×10 5 cells with 1.0 mg of DNA by the calcium phosphate precipitation method (Wigler, et al., 1977). Transfectants were selected in Geneticin (750 mg/ml) and passaged twice prior to characterization of growth properties in vitro and in vivo.
Cell Proliferation Assay
For analysis of proliferation in semi-solid medium, 1×10 4 and 1×10 3 cells were suspended in 0.4% agarose (SeaPlaque, FMC) in DMEM supplemented with 10% CS as described elsewhere (DiFiore, et al., 1987). Colonies were stained with p-iodonitrotetrazolium violet (Sigma) and scored after 2 weeks. For analysis of tumor forming capacity, around 1-5×10 5 cells were injected subcutaneously into athymic nude mice as described (Heidaran, et al., 1990). Tumor occurrence and size were monitored at least once weekly for 5 weeks.
Detection of Mutations
For the reverse transcriptasepolymerase chain reactions ("RT-PCR"), 10 mg of total RNA was reverse-transcribed by MuLV reverse transcriptase (Gibco-BRL) to synthesize first strand cDNAs with random oligonucleotide primers in a final reaction volume of 50 ml. 4 ml of the first strand reaction was used in a 50 ml PCR reaction with primers "A" (5' ATAGATGACAGAGCAGCCCGGCTA 3') (SEQ ID NO:6) and "B" (5' GATAGAGGCAGTTTTGAAGAAATC 3') (SEQ ID NO:7) under the following cycling conditions: 94° C., 1 min., 57° C., 2 min., and 72° C., 3 min. for 30 cycles. Reactions were separated on an 1.3% agarose gel and the 143 bp PCR-amplified products were extracted from the gel by a QIAEX kit (Qiagen). Purified fragments were then digested with BfaI enzyme (New England Biolab) and electrophoresis was performed on a 4% agarose gel. DNA fragments were then transferred onto a nitrocellulose membrane and hybridized to a 32P!-labeled oligonucleotide probe (tc26) under standard conditions (Maniatis, et al., 1982). Following stringency wash of the filter, membrane was exposed to X-ray film (Kodak) at -70° C. for 3 hours.
Site-directed mutagenesis
The human wild-type R-ras coding region (nucleotide 1-657) was generated by polymerase chain reaction (PCR) method from a human cDNA library with an BamHI-tagged (+) primer (5'-AAAGGATCCATGAGCAGCGGGGCGGCGTCCG-3') (p5) (SEQ ID NO:8) and an EcoRI-tagged (-) primer (5'-AAAGAATTCCTACAGCAGGACGCAGGGGCA-3') (p10) (SEQ ID NO:9). PCR amplified product was subcloned into the multiple cloning site of an eukaryotic expression vector, pCEV29 and was sequenced to confirm authenticity. The R-ras point mutants were generated from the wild-type construct using a two-step PCR method (Gak et al., 1992). First, complementary mutant oligonucleotides were designed for position 38 (5'-TCGTGGGCGGCGTCGGCGTGGGCAA-3') (SEQ ID NO:10) and position 87 (5'-GACACCGCGGGCCTGGAAGAGTTC) (SEQ ID NO:11) for PCR separately with the upstream p5 primer and the downstream p10 primer (see above) under the following conditions: 94° C., 1 min; 45° C., 1 min; 72° C., 2 min; 25 cycles. The two PCR products amplified for each position were mixed and used as templates for a subsequent PCR reaction using the p5 and p10 primers under the following conditions: 94° C., 1 min; 58° C., 2 min; 72° C., 3 min; 30 cycles. PCR products were digested with restriction enzymes and subcloned into pCEV29 vector.
Northern Analysis
Total RNA was isolated from cell lines by RNAzol solution (Cinn/Biotecx Labs. Int. Inc.) as described by the manufacturer. After separating samples by electrophoresis on 1% denaturing formaldehyde agarose gel, RNAs were transferred to nitrocellulose filters (Maniatis, et al., 1982). A tissue RNA blot was purchased from Clontech (Palo Alto, Calif.). Blots were hybridized at 42° C. for 12 hours with 32P!-labeled DNA probes in 40% formamide, 6× saline sodium citrate (SSC), 5× Denhardt's solution, 1% SDS, 10% dextran sulfate and sonicated salmon sperm DNA (50 mg/ml). After the hybridization reactions, filters were washed twice in 1× SSC and 0.1% SDS at room temperature and in 0.1×SSC and 0.1% SDS at 55° C. Filters were dried and exposed to X-ray films at -70° C. for various times.
In vitro transcription/translation
A TNT in vitro transcription/translation kit was purchased from Promega. Approximately 1 mg of circular plasmid was added to each reaction of rabbit reticulocyte lysate in the presence of 40 mCi of 35S! methionine (NEN, Dupont, 10 mCi/ml; specific activity, 1078 Ci/mmol) and Sp6 RNA polymerase in a final volume of 50 ml. Reaction mixtures were incubated at 30° C. for 90 minutes. Samples (5 ml) were then boiled in Laemmli sample buffer and protein products were resolved by 10% polyacrylamide gel electrophoresis (SDS-PAGE). Gels were dried and exposed to X-ray films at -70° C. for 6-12 hours.
Cell Proliferation assay
For analysis of proliferation in semi-solid medium, 1×10 4 and 1×10 5 cells were suspended in 0.5% agarose (SeaPlaque, FMC) in 10% CS as described in DiFiore et al., 1987. Colonies were stained and scored after 2 weeks. For analysis of tumor forming capacity, around 1.0×10 5 cells were injected subcutaneously into athymic nude mice as described (Heidaran et al., 1990). Tumor occurrence and size were monitored weekly.
Western blotting
Mass-selected cultures were lysed with HEPES solubilizing solution (50 mM HEPES, Na 4 PO 2 , 4 mM EDTA, 10% Triton X-100) and 100 mg of protein was loaded per lane on an 12.5% SDS-PAGE gel. Following transfer onto Immobilon-P membrane (Millipore, Bedford, Mass.), R-ras protein was detected by a Pan-ras monoclonal antibodies, M90 (Lacal, et al., 1986).
Example 1
Expression Cloning of a Transforming Gene from a Human ovarian Tumor cDNA Library
A λpCEV29 cDNA expression library was generated from a late passage of the A2780 cell line established from a metastatic human ovarian carcinoma (Eva, et al., 1982). For analysis of transforming cDNAs, library DNA was used to transfect NIH/3T3 cells. A distinct class of morphologically transformed foci consisting of rapidly-growing, highly retractile cells (FIG. 1) was identified at a frequency of about 1 focus-forming units per plate ("ffu/plate"). Two independent foci (64-1 and 66-1) from separate plates were isolated and shown to exhibit G418 resistance (a neomycin resistance detection agent), indicating that each had taken up and stably integrated the vector. Plasmid rescue was performed as described in Miki, et al. (1991), and the transforming cDNAs were identified based on their high-titred transforming activities (>10 4 ffu/pmol) and ability to confer a similar transformed morphology.
Restriction enzyme analysis revealed cDNA inserts of 1.9 and 2.4 kb (kilobase pairs) for plasmids rescued from foci 64-1 and 66-1, respectively. Moreover, the two cDNA clones displayed the same pattern with BamHI, HindIII and XbaI restriction enzymes, suggesting that they were different cDNAs generated from the same gene (FIG. 2A). The nucleotide sequence of clone 66-1 revealed an open reading frame of 612 bp (base pairs) flanked by 6 bp and ˜1.7 kb of 5'- and 3'-untranslated regions, respectively. The open reading frame predicted a protein species of 204 amino acids with a calculated molecular mass of ˜23 kDa (kilodaltons) (FIG. 2A). A search in the GenBank Database uncovered extensive sequence identity to TC21, a member of the superfamily (Drivas, et al., 1990). TC21 was initially cloned from a human teratocarcinoma cDNA library by polymerase chain reaction (PCR) methodology using degenerate oligonucleotides to the conserved region of the ras genes (Drivas, et al., 1990).
Example 2
TC21 Oncogene is Point-Mutated at Codon 72
Detailed comparison between TC21 and 66-1 identified nucleotide sequence disparities in two regions of the coding sequence. First, three additional nucleotides were present at positions 11, 20, and 33 in the N-terminal region of 66-1 leading to frame-shifts, which resulted in replacement of amino acid residues from codons 5 to 10 (AGGRLR) in TC21 with (GWRDGSG) in 66-1 (FIG. 2B). However, the addition of these three base pairs restored the reading frame at amino acid position 12 of TC21. Our sequence determined for 66-1 was identical to that of a cDNA clone which we isolated from a normal human epithelial cell library, indicating that this region was identical in both the 66-1 oncogene and wild-type allele. Thus, we attribute differences from that reported for TC21 in this region (Drivas, et al., 1990) to sequencing variations arising from the high GC content in this region.
The second disparity involved a region in which the sequences of both the TC21 and the normal human epithelial cell cDNA were identical. This alteration involved an A:T to T:A transversion in the second nucleotide of codon 72, resulting in the substitution of glutamine (CAA) by leucine (CTA) in the 66-1 oncogene (FIG. 2C). Gln72 corresponds exactly to Gln61 in the Harvey-ras (H-ras) proto-oncogene product, a position frequently mutated and responsible for activation of the H-ras oncogene in a variety of human tumors (Yuasa, et al., 1983; Bos, 1989). The same mutational alteration was also present in clone 64-1, indicating that both transforming cDNAs were derived from transcripts expressed from a point-mutated allele of the wild-type TC21 gene.
Example 3
Codon 72 Mutation Activates TC21 Oncogenicity
In order to assess the effects of the single A to T transversion on TC21 biological properties, we compared transforming activities of the normal and mutant cDNAs by NIH/3T3 transfection analysis. As shown in Table 1, the mutant exhibited transforming activity of >10 4 ffu/pmol when either 64-1 or 66-1 plasmids were used. In striking contrast, the wild-type TC21 allele expressed under the influence of the same promoter showed no detectable transforming activity.
These results established the mutation as being responsible for TC21 oncogene activation. Table 1 shows that the TC21 oncogene was almost as active as an H-ras oncogene. However, the wild-type H-ras allele was significantly more active than the wild-type TC21 (Table 1). We next analyzed mass populations of marker-selected cells for other properties of transformed cells including growth in semi-solid agar-containing medium and tumorigenicity upon subcutaneous inoculation of athymic nude mice. Cells expressing the TC21 mutant exhibited a highly transformed phenotype, inducing colony formation in agar and tumors in animals at efficiencies comparable to those of cells expressing an oncogenically activated H-ras mutant (Table 1). All these findings established that the mutation was responsible for activation of TC21 oncogenic properties in transfected NIH/3T3 cells.
TABLE 1______________________________________Transforming Properties of the 66-1 Oncogene Soft-agar Transforming colony Tumorigenicity efficiency.sup.a formation.sup.b (no. tumors/noTransfectant (ffu/pmol) (%) inoculated)______________________________________pSVneo <1.0 × 10.sup.0 <1.0 0/6H-ras.sup.wt 2.5 × 10.sup.2 ND NDH-ras.sup.val12 5.0 × 10.sup.4 23.6 7/7TC21.sup.wt <1.0 × 10.sup.0 ND NDTC21.sup.Leu72 6.0 × 10.sup.4 21.6 7/7______________________________________ .sup.a NIH3T3 cells were transfected with different amounts of each plasmid DNA and the number of foci scored after 3 weeks in culture. All 3 plasmid DNAs produced similar numbers of marker selectable colonies (˜10.sup.4 colonies/μg). .sup.b NIH/3T3 cells were transfected with 1 μg of each plasmid, and mass populations were markerselected. Each markerselected culture was suspended in 0.4% semisolid agarose in medium supplemented with 10% CS. Colonies of more than 300 cells were scored after 14 days and results represent means values of duplicate plates. .sup.c ˜4 × 10.sup.4 markerselected cells were inoculated subcutaneously into athymic nude mice. Animals were monitored at least twice weekly for 5 weeks for the appearance of >0.5 cm.sup.2 tumors at th inoculation site. .sup.d The 641 and 661 plasmids exhibited similar transforming efficiencies. NDnot determined.
A2780 ovarian tumor cells contain the TC21 codon 72 mutation
To establish that the codon 72 mutation was present in the ovarian tumor cell line, advantage was taken of the creation of a polymorphic restriction enzyme site, BfaI (C/TAG), when an A:T to T:A transversion occurs in the second base pair of the tetranucleotide wild-type sequence (CAAG) (FIG. 3A). PCR primers flanking the mutation site were generated to produce an amplified product of 143 bp. An additional BfaI site 24 bp upstream from Gln 72 was included in the PCR product to serve as an internal control for the restriction enzyme reaction. Total cellular RNAs were prepared from 3 different A2780 lines corresponding to early (A2780E, ˜20), middle (A2780M, ˜50), and late (A2780L, >200) passage cells. In parallel, control cell RNAs were prepared from a normal mammary epithelial cell line, AB589, a Ewing's sarcoma cell line, SK-ES-1, and NIH/3T3 cells transformed by the 66-1 plasmid.
As shown in FIG. 3B, two DNA fragments were observed in samples derived from normal human cells and Ewing's sarcoma cells. The upper 143 bp band represented undigested DNA, and the lower 119 bp band represented the product generated by cleavage at the internal control BfaI site. The restriction fragments produced by BfaI digestion of the PCR product from 66-1 transformed NIH/3T3 cells contained an additional 95 bp fragment, consistent with the size expected if cleavage occurred at both control and polymorphic BfaI sites (FIG. 3B). This 95 bp mutant-specific restriction fragment was also observed in all 3 passages of the A2780 tumor cell line, indicating that the TC21 gene was oncogenically activated in the initially established human ovarian cancer line.
Example 5
Lack of Transforming Activity of A2780 Genomic DNA
To investigate the detectability of the mutant TC21 oncogene within A2780 tumor cells by standard genomic transfer, we performed transfection experiments with high molecular weight DNAs isolated from both A2780E and A2780L cells. As controls, genomic DNAs were prepared from T24/EJ bladder carcinoma cells containing a mutated H-ras oncogene and NIH/3T3 cells transfected with the TC21 oncogene cDNA. As shown in Table 2, genomic DNAs isolated from EJ as well as TC21 transformed NIH/3T3 cells induced transformed foci at comparable efficiencies (20-50 ffu/plate). In striking contrast, A2780 genomic DNAs showed no detectable focus forming activity in several experiments. These results establish that the TC21 oncogene would have evaded detection by standard genomic DNA mediated gene transfer approaches.
TABLE 2______________________________________Transforming Activities of Different Genomic DNAs Transforming efficiency.sup.a (ffu/pmol)DNA Source Oncogene exp. 1 exp. 2 exp. 3______________________________________EJ H-ras.sup.val12 ˜30 30, 25, 30 20, 2566-1 TC21.sup.leu72 ˜50 ND 30, 30,transfected 50, 50NIH/3T3A2708.sup.E TC21.sup.leu72 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0A2780.sup.L TC21.sup.leu72 0, 0, 0, 0 ND 0, 0, 0, 0______________________________________ .sup.a NIH3T3 cells were transfected with different 50 μg of each genomic DNA per plate, and the number of foci were scored after 3 weeks i culture. Data shown here were generated from 3 independent experiments, and each number represents results from a single plate. NDnot determined.
Example 6
Expression of TC21 Transcripts
We sought to characterize TC21 transcripts present in normal cells and the A2780 ovarian tumor line. FIG. 4A demonstrates expression of a major 2.5 kb and minor 1.7 kb transcript in A2780 cells at each of several different passage levels. TC21 transcripts of the same respective mobilities were observed at similar relative levels in AB589 human epithelial cells. Thus, oncogene activation was not associated with any gross mRNA size alterations. It should be noted that the 2.4 kb cDNA isolated by expression cloning must represent essentially the full length major transcript. NIH/3T3 cells also expressed two TC21 transcripts of similar respective sizes at somewhat lower but detectable levels. FIG. 4B shows that the two TC21 transcripts were ubiquitously present in all human tissues examined with the highest levels in heart, placenta, and skeletal muscle. Moderate levels were detected in lung and liver, while low levels were observed in brain, kidney, and pancreas.
Example 7
Construction of R-ras mutant plasmids
Previous studies failed to demonstrate that R-ras was capable of transforming activity in Rat-1A fibroblasts (Lowe & Goeddel, 1987). We sought to examine this finding by generating codon 87 (position 61 in H-ras) as well as codon 38 (position 12 in H-ras) mutants for focus formation assay in NIH/3T3 fibroblasts. A guanine ("G") to thymine ("T") base substitution was introduced by polymerase chain reaction (PCR) at the second base pair of codon 38, replacing glycine (GGC) with a valine (GTC) residue (R- val38 ). Similarly, the glutamine (CAG) residue at position 87 was replaced by a leucine (CTG) residue through an A to T transition (R- leu87 ). Analogous mutations in the human oncogenes have been commonly detected in human tumor samples (Bos, 1989). Each R-ras mutant as well as the wild-type allele were subcloned into an eukaryotic expression vector, pCEV29 under the transcriptional control of a MuLV Long Terminal Repeat (LTR) promoter. To ascertain the integrity of our constructs and to detect the putative products generated from each plasmid, cDNA sequences were in vitro transcribed and translated in the presence of 35S! methionine. As shown in FIG. 5, protein species of ˜23 kilodalton (kDa) were observed in samples derived from wild-type and mutant plasmids, consistent with the predicted size of the human R-ras gene product. It might be noted that while the present example shows specific mutations, it is contemplated that other amino acid mutations would provide similar results.
Example 8
Transforming properties of R-ras mutants
To examine the transforming potential of our cDNA clones, plasmid DNAs carrying various ras constructs were transfected into NIH/3T3 cells by the calcium phosphate precipitation method (Wigler et al., 1977). As controls, parallel cultures were transfected with pSV2neo , the wild-type (H-ras wt ) or a valine 12 mutant (H-ras val12 ) of the H-ras gene. We also included both wild-type (TC21 wt ) and mutant (TC21 leu87 ) forms of TC21 gene. As shown in Table 3, both R-ras val138 and R-ras leu87 DNAs demonstrated high titered focus forming ability (10 3 -10 4 ffu/mg) with transformed cells appearing within 10 days following transfection. Among the mutant ras-related genes examined, H-ras val12 possessed the highest specific transforming activity, followed by TC21 leu72 and further lowered transforming activity was observed with the two R-ras mutants. In addition, R-ras mutant foci displayed morphological features that were distinct from the classical ras transformed foci. Position 87 mutant induced foci exhibited an overall dense, rounded appearance and were comprised of small, rounded and highly retractile cells (FIG. 6). In contrast, position 38 mutant induced foci were characterized by areas of high cell density with flatter and less refractile cells. Of note, no transformed foci were observed in cultures transfected with an R-ras wt construct, whereas the wild-type H-ras wt gene driven by a similar promoter produced ˜10 3 ffu/mg of focus forming efficiency.
TABLE 3______________________________________Transforming Properties of Expression Plasmids Specific Transforming Colony-forming transforming efficiency.sup.a efficiency activityPlasmid (ffu/μg) (cfu/μg) (ffu/cfu)______________________________________pSV2neo <1.0 × 10.sup.0 1.0 × 10.sup.4 >10.sup.-4H-ras.sup.wt 1.0 × 10.sup.3 1.0 × 10.sup.5 0.01H-ras.sup.val12 3.0 × 10.sup.4 2.0 × 10.sup.4 1.5TC21.sup.wt <1.0 × 10.sup.0 1.0 × 10.sup.5 <10-5TC21.sup.Leu72 1.0 × 10.sup.5 3.0 × 10.sup.5 0.3R-ras.sup.wt <1.0 × 10.sup.0 1.0 × 10.sup.5 <10-5R-ras.sup.val38 2.0 × 10.sup.3 1.0 × 10.sup.5 0.02R-ras.sup.Leu87 1.0 × 10.sup.4 1.0 × 10.sup.5 0.1______________________________________ .sup.a NIH3T3 cells were transfected with various concentrations of each plasmid and number of foci was scored after 3 weeks in cultures. All plasmids are of equivalent sizes.
To demonstrate that the R-ras mutants induced a transformed phenotype typical of classical oncogenes, marker-selected mass cultures were generated for in vitro and in vivo analysis. R-ras val38 and R-ras leu87 transfected NIH/3T3 cells formed large, progressively growing colonies in soft agar at high frequency. In contrast, NIH/3T3 cells transfected with R-ras wt and control pSV2neo produced significantly lower numbers of colonies. Inoculation of R-ras val38 or R-ras leu87 transfectants subcutaneously into athymic nude mice induced tumors at high frequency within three weeks. In contrast, no tumors were observed with pSV2neo control cells as late as 7 weeks. All of these data provided strong evidence that codon 38 and 87 mutants of the R-ras gene can function as oncogenes, inducing morphological and malignant transformation both in vitro and in vivo.
Example 9
Expression of the R-ras gene product in transformants
To identify the R-ras protein product in R-ras transformed cells, marker-selected mass cultures were subjected to Western analysis using a Pan-ras antibody, M90 (Lacal, et al., 1986) that recognizes the R-ras gene product. As shown in FIG. 7A, M90 antibodies cross-reacted efficiently with H-ras p21 proteins. Similarly, R-ras p23 gene products were also readily detected in cells transfected with either mutant R-ras plasmids to a level ˜50-fold higher than in cells transfected with the pSV2neo .
To search for cell types in which R-ras gene was preferentially expressed, Northern blot analysis was performed with poly(A)+RNA isolated from a wide spectrum of human tissues. As shown in FIG. 7B, the 4.6 kb and 1.2 kb transcripts of the R-ras gene, which may derive from alternative splicing events, were ubiquitously expressed in all tissues examined. Interestingly, the relative ratio of these two transcripts varied widely in different tissue types with the larger 4.6 kb transcript expressed at a higher level in skeletal muscle and the smaller 1.2 kb transcript preferentially overexpressed in heart.
Example 10
Cooperation between R-ras and c-raf-1
A previous study demonstrated the cooperative effect of H-ras and c-raf-1 genes in transforming NIH/3T3 cells (Cuadrado et al., 1993). To test whether R-ras shares downstream effectors with H-ras, co-transfection experiments were performed with the c-raf-1 plasmid and either the R-ras wt or R-ras val38 plasmids. As controls, analogous experiments were performed using the H-ras wt gene under control of its own promoter so as to give a low level of focus-forming frequency (10-20 ffu/plate). As shown in Table 4, whereas the c-raf-1 plasmid alone did not yield detectable transformed foci, co-transfection with 0.1 mg of the H-ras wt construct increased the number of ras transformed foci by 4 to 5 fold. We were unable to detect any transformed foci upon co-transfection of c-raf-1 and R-ras wt . However, when a sub-threshold level (1 ng) of R-ras val38 was used in the co-transfection experiments with c-raf-1, we observed a marked increase in focus formation efficiency of >15 ffu/plate. This cooperative effect was reproducibly obtained in a separate experiment with quantitative enhancement of focus-forming-units with increasing amount of R-ras val38 plasmid.
TABLE 4______________________________________Analysis of cooperative transformation ofNIH/3T3 cells by R-ras and c-raf-1.sup.a Exp. 1 Exp. 2 -- pCEV29 c-raf-1 -- c-raf-1______________________________________H-ras.sup.wt (0.1 μg) 10 1,0 50, 50 15 60, 70H-ras.sup.wt (1.0 μg) 0, 0 0, 0 0, 0 ND NDR-ras.sup.val38 (5 ng) ND ND ND 0 21, 26R-ras.sup.val38 (1 ng) 0, 0 0, 0 15, 20 0 2, 4______________________________________ .sup.a H-ras or Rras plasmids at indicated amounts were cotransfected wit either no plasmid (--) or 1.0 μg each of pCEV29 or craf-1 expression plasmids. The number of focus forming unit produced in each plate from tw separate experiments is indicated. ND not determined.
Example 11
To screen for mutations of TC21 and R-ras genes in human tumor samples, we have a sensitive polymerase chain reaction (PCR) based single-stranded conformation polymorphism (SSCP) analysis (Orita, et al., 1989; Orita, et al., 1989) that could detect single base alterations in DNA samples. Briefly, PCR primers flanking hot spots (positions 24 and 72 of TC21; positions 38 and 37 of R-ras of both genes are used to amplify those regions from human tumor DNA samples and analyze on a denaturing polyacrylamide gel. Changes in base compositions due to mutational alteration theoretically modify the physical structure and therefore other the mobility of the amplified single-stranded DNA when comparing to the wild-type sequence.
Based on this method, we are able, using plasmids corresponding to both wild-type and position 72 mutant alleles of TC21, to generate optimal conditions for SSCP analysis with the observation of distinct mobility shift for both wild-type and mutant sequences. We are developing conditions for SSCP analysis of other positions in TC21 as well as R-ras.
The hereinbelow list of references provides a complete citation of each of the references cited hereinabove. All of the references mentioned in the present application are incorporated in toto into this application by reference thereto.
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__________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 11(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 2336(B) TYPE: Nucleic Acid(C) STRANDEDNESS: Double(D) TOPOLOGY: Linear(ii) MOLECULE TYPE: cDNA(iii) HYPOTHETICAL: No(vi) ORIGINAL SOURCE:(A) ORGANISM: Human(B) STRAIN:(C) INDIVIDUAL ISOLATE:(D) DEVELOPMENTAL STAGE:(E) HAPLOTYPE:(F) TISSUE TYPE:(G) CELL TYPE:(H) CELL LINE:(I) ORGANELLE:(ix) FEATURE:(A) NAME/KEY: R-ras gene(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: exon 1, intron A(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:GAATTCGGGTCCCCCCAAGCCAGTGCCCTCGCTCGGATCC40AGAATCCTGGGTCCCCAGCCTCTCCAATTCCTGGACCTAA80GAGTCCAGGCCCCCGGCTCCCTCCTTTACCGAACCTAGTA120CGAAGGAACCTGTCTACCTTCCTCCCTGACACCCTCCTCC160CCAGGACCCAGGAGTCCACATCTCCAGCCCCATTTTCTCC200TAAGGACCCAGGAGTCTGGGCCCTCTGCTTCCTTCTCCTT240CAAGACCCAGAAATCCTGGCCCCAGGCTCTTCATGACCCA280GGCATCCCTACTTGGGCGAGCTGGCTCATGGATTAGGAAT320GCAGTGATCTCACGGCCCCTCCCTGCCCCGTTACCCTGCT360GTCCCCCTCTAGGGCCCCACTCTCCTCCCAGTCTGTCTTC400CGCTTGGCTGGGACAGCGGGAACCGGAAGCCTGGGTCCCT440TAGCGGGCGGAGACTCTAGCTTCTAACCCAGACGCCGGGG480TCGAAAGCTTGGCTAGGATCCCAGGAGGGAGGTGGAGCTA520CTCCTCAAAACCTGCTGCTTCCTCGGAGCGCCCTATATAC560GGCCGCGCGCGCGAGTCGACGAGCTCCGCCTACCATACTA600AGGCCTCGGAGACGATGCCCCAAGCAGCAGTGTCACAGGG640GTCCTTATTTGCATAGCCCCTCCCCTGAGGAACTTTCCGC680CCCGTCTGCTGAAAGAATAAATTCTTATTAGCATAGCCAC720GCCCACAGACCGCCCTCCCGCTGAGAGCGCGTGGCGCCGC760TCAGGGCAAAGCACAGGTCTCTCATTAGCATAGCCCCGCC800TCATTCGGAATTCCCCTTCGCAGCGAACGCCGTTCCCTTT840CCCTTATTAACATAGCTCCTCCCTTTCTTTGGCCCGTCCC880CCTCCTTAAGTGTCCGGAGACGCGAGCCCTCCTTGCCAGA920GCTCATGATTATGCAGTAGCCTCATTAGCGTAGCCCGCCC960CCCCGGGTCCCGCCCGGCTCCCCCGCAGGCGGTAGCGAAG1000GCAGCAGCAGCGGTGGCGACATGAGCAGCGGNNNGGCGTC1040CGGGACAGGGCGGGGGCGGCCCCGGGGCGGGGGACCTGGG1080CCCGGGGACCCCCCGCCCAGCGAGACACACAAGCTGGTGG1120TCGTGGGCGGCGGCGGCGTGGGCAAGAGCGCGCTGACCAT1160CCAGTTCATCCAGGTAGTGGGCCCTCACCCGGGAGGTGTC1200CCCCGGGACCCAGAACTGAGCCTTGGGGGGATCCCCGAGA1240CCCCTTTTCCCCCTTGACCCATCACTGAGACCCTCCTATA1280AGGCCCTCTAATCTTAAAAGATCCCCACAGATTGTAACCT1320AAACTCTTGGAGAGCCTCCATCCCCTGCACGGGGGACCCT1360TCCTTCTGCACTCGCATCCCGAGACCCACTATTCCCTCTC1400CCAGTGCCTAAGACCCCGCTTACCTGCTGACCTGGCTTTG1440AGCACCTCCTGGGAGCATGCTAAATACAAAATACTCACCC1480CATTCGGACCCTAAGCACTCCCAGGACCCCCACCACGCCC1520TTGGTGCCACCTTCCACCACCCTGAGCCCTATCTCCCCCA1560AATCCCAGTCCCCAACTTCCCCTCTAAGCCATTGAGAGCC1600TTCCTGGGAGAATGCCAGTGCCCAGCACTTTGAGATTCCA1640CCACGTTCGATTCTTTTTTTTCTTTTTTTTTTTTTTTTGA1680GACAGAGTCTCACTCACTCTGTCACCCAGGCTGGAGTGCG1720GTGGAGTGCAGTGGTGCGATGTTGGCTCACTGCAACCTCT1760GCCTCCTGGATTCAAGCAATTCTCCTGCCTCAGCCTCCCA1800AGTAGCTGAGACTACAGGCGAGTGCACCATGCCTGGCTAA1840TTTTTGTATTTTTTAGTAGAGACGGGGTTTCACCATATTG1880GACTGGTCTCGAACTCCTGACCTCGTGATCGGCCTGCCTT1920GGACTCCCAAAGTGCTGGGATTACAGGCATGAGCCACCGT1960GCCCGGCCCCACGTTTGATTCTTAGCCCCTTCCATGACTG2000CCCCCAGAATCTAGAAATTCTACCCAGACCCTGGCCCTGA2040GACTCTTCTGGGACTACCCAGTCCTAAGAGAGTCCTGCTC2080TCCGACCCGAGATTTAAAAAGACATCCTGCCCCTTGGCCA2120TTCCAGAAATCTCCAAGACCCCAAGTCCTGACAATCCCCC2160ATTCCCGGAGGCCCAAACCTCCACTCTCCCACCCCACCCC2200CAAGGAAAACCAGCCCCTCCTCCATCCCATGCTTTCTCCG2240CTGCAACTCCCTGAGCCCCTCTCAGAAACCCTGAATAGCT2280CTCAAATCATCTCCATGGAAGAAGCCCCCAGATTCTTGGC2320ACCCCCAGAAAGATCT2336(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 3350(B) TYPE: Nucleic acid(C) STRANDEDNESS: Double(D) TOPOLOGY: Linear(ii) MOLECULE TYPE: cDNA(iii) HYPOTHETICAL: No(vi) ORIGINAL SOURCE:(A) ORGANISM: Human(B) STRAIN:(C) INDIVIDUAL ISOLATE:(D) DEVELOPMENTAL STAGE:(E) HAPLOTYPE:(F) TISSUE TYPE:(G) CELL TYPE:(H) CELL LINE:(I) ORGANELLE:(ix) FEATURE:(A) NAME/KEY: Human R-ras gene(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: exons 2- 6.(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:AGCTACCCAAAGAGAAGGGGACAGAGACCCAGAGAGAGAG40AGTAATAGAGACTCAGAGAGACAGAGGGGACAGAGACCCA80GAGAAAAGGGGGCAGAGACCCAGCAACAAGGACAGACATC120TGGAGAGAGAGAGAAGGACAGGGCAGGGCGCAGTGGCTCA160CATCTGTAATCCCAGCACTTTGGGAGACCCAGGCGGGCGG200ATCACCTGAGGTCAGGAGTTCGAGACCAGCCTGACCAACA240CAGCCTGACCAACACATCTCTACTAAAAATACAAAATTAG280CCAGGTGTGGTGGCGCATGCCTGTAATCCCAGCTACTTGG320GAGGCTGAGGCAGGAGAATCTCTTGAACCCAGGAGGCAGA360GGTTGCAGTGAGCCGAGATCTCGCCATTGCACTCCAGCCT400GTGCAACAAGAGCGAAACTCCGTCTCAAAAAAAAAAAAAA440AAAAAAAAAGATTCAGAGAGACAGACGGGACAGAGACCCA480GAGAAAAGGGGGCAGAGACCCAGCAACAGGGACAGACATT520TAGAGAGAGAGGGACAGAGACTGAGAGAGGCATCCCAAGG560GCAGGGCTTCGTCCTGTCTGCCGGGGCACTGCAGTAACTA600TCCTCTCCCCACCCCGCCAGTCCTACTTCGTGTCTGACTA640CGACCCCACTATTGAGGACTCCTACACGAAGATCTGCAGT680GTGGATGGCATCCCAGCCCGGCTGGACAGTGAGGGCGGCA720AGGATGGATGATGGATGGGGGTGGTGTCAGTGGGGGCTGA760GTGCTCTTGGGGGTGACTGCGGGGAGCCTGGTCCCCACAA800TGGCCCCTCTCCCTGTCTCTGCAGTCCTGGACACCGCGGG840CNNNGAAGAGTTCGGGGCCATGAGAGAGCAGTACATGCGT880GCTGGCCACGGCTTCCTGCTGGTGTTCGCCATTAATGACC920GGCAGAGGTGACAGGGGTTACTGGTGGCGGAGCAGTGGGT960GGGTGTGGGGAGGACCTGGGCTCTGCAGCTGGCTGGACCT1000CATGCCTCCGGCTTCACTCGCAGTTTCAACGAGGTGGGCA1040AGCTCTTCACGCAGATTCTGCGGGTCAAGGACCGCGACGA1080CTTCCCCGTTGTGTTGGTCGGGAACAAGGCAGATCTGGAG1120TCACAGCGCCAGGTTCGGGACACCCCTCTTTCTGGGGACC1160CCATCTCAGTCTGGGAGGCTCCTTCCAGCACACCTGTCCC1200CCATCAGCATCCTCCTCTGTTCCTGCAGTGCTGCGACTGC1240CACTGTCACACAGCTCACCTAGATGGGTTACCCCCAAACT1280GGACCTTCAGGGTCCCCGGCATCACCGAGCAGAGGGCCTA1320GCATGCAAGTGTCCTCAGGAGAGGCTGCTGGACGGAACAA1360AGGACATTCACCCCCCGTCCGCCAGCTCTCTTTGCCCCTT1400CCTCGCATTCCTCCCTTCCAGCCAACCTCCCACCAGCCCC1440AGCACCTCCCCTGCTCATGGCCGGCCCCCTCCATGGCTCC1480CCAGTTCCTCCCCAGGTGCCAGATGCCCCGCACAGTTGCG1520CCCCTCCTTTCCCTGCTCCCATCACTTCCCCCACAACGAT1560TTCCACACAGAACTCATCCATCTGGCAAAGGCTCTGGGGA1600TTTCCAGGCTTTGGGGTTCCGCCTGCCTCTGCCGGGAACA1640CCCTGACTTCCCTGCCTGCCCACTCCTGGTTATCTAAGGC1680ATAGCAGGGCAAGTGCCCACGAAGCCTGCCCCCATCCCTT1720ACTTAGAAGACACCAAGCCCCTGCGGCATCTCCCTCCATA1760ATCTCTCAGGAGCTCTTCCTCTTTGAGTTCTCACAGTGGG1800TCACCTCTCCTAGAGTATCCAGCCTGCCTGTCTGTCTCTC1840TGGCTGCGGTCACCCTGAGTGCAGGGACCTGACTCCCCCG1880TGTCCCCCCTACCCCCAGGTCCCCCGATCAGAAGCCTCTG1920CCTTCGGCGCCTCCCACCACGTGGCCTACTTTGAGGCCTC1960GGCCAAACTGCGTCTCAACGTGGACGAGGCTTTTGAGCAG2000CTGGTGCGGGCTGTCCGGTGAGCCAAGTCCCCTTCCTGTC2040GTCCTTGTCCCCAGCCCTTCCACTCCAAACTCACTGGCGT2080TTTCCCACAGGAAATACCAGGAACAAGAGCTCCCACCGAG2120CCCTCCCAGTGCCCCCAGGAAGAAGGGCGGGGGCTGCCCC2160TGCGTCCTCCTGTAGCCCAGGCAAGAGAGAAGCAACCACC2200ACAAGCTCTCGGGACTAGCTGCCTTCGCACCTTGCTGTGT2240GACCTGAGGCCCTCACTGAGCCTCAATTTCCTCATCTGGG2280TCTCCCAGGACACATCACATACCCACCCTTACTTCCTGGC2320CTCTTCTGGGCTACTGCCACTGTGTGCCTTCTGCCAACGC2360CTCCTGTCCCCACCTAAGCCTGGTGGGGGTGAGGGGCTCC2400GGGTCACTGCTGTATATAACTCCCCTCCCCCAGAAAAATA2440AATGTCACTGCCAACGTCAGGAGGTGCTTTCTAAAAAGGT2480AATGAGGGTCGGGCACTGTGGCTCACTCCTGTAATCGCAG2520CATTTTGGGAGGCCAATGCGGGAGGACCGCTTGAGTCCAG2560GAGTTTTTGACCAGCCTGGGCAGCATAGCGAGACCCCCAT2600CTCTTAAAAAAAAAGGGTGGGGGAATGAACTCTGGGAAGG2640TGAACGAATTCATGCCACATAGCGAGACCCCATCTCTACA2680ACAAAATGAAAAATTAGCCAAGTGTGCACTCGTAGTCCCA2720GCTACTTGGGAGGCTGAGGCAGGAGGATTGCTTGAGCCCA2760GGAGGTTGAGGCTACAGAGTTGTGATCACGCGACTGCACT2800CCAGCCTGGGCAACACAGTGACACCCTGTCTCAAATAAAT2840AAATAAAATGTAAAAAACGAAGTGTTCCTAGGACACAGAT2880GGGCTTTGGGTATCCAGACTGAAGTGTGTCATCCATTTAC2920CCACTGTGGCCTTAAGACACCCAACACTTCTGCTTCTCCC2960AGGACAGAATAGGGGGTTGGATGGGGGATGTCCACACTGA3000CCCCAAATTGGATTAAGTGTTTAGATTCAGATTTCAGTGC3040TACTGGGAACTTTCTGAAAATGAGGACTTGCCAGACGGCT3080GCTTGGACACCATTCCACCCACCTGTCCCTTCTCGATATA3120CATTGAAGGTGAGAGTGGGACAGGCAGGGTTTGTAGCAGT3160TGCTCCCTGTCTCTATTTTTGTAGACAGAGTCTAGCTCTT3200GCCCAGGCTGGTCTCAAACTCCTGGCCTCAAGTGATCCAC3240CCATTTCGGTCTCCCAAAGTACTGGGCTTACAAGCGTGAG3280CTACCACACCCAGCAGCTGAGTTGCTGCCTGTCTCCAATG3320TCCTAGAACGTTCTATTGGAATGTTCTAGA3350(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 218(B) TYPE: Amino acid(C) STRANDEDNESS:(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: Protein(iii) HYPOTHETICAL: No(vi) ORIGINAL SOURCE:(A) ORGANISM: Human(B) STRAIN:(C) INDIVIDUAL ISOLATE:(D) DEVELOPMENTAL STAGE:(E) HAPLOTYPE:(F) TISSUE TYPE:(G) CELL TYPE:(H) CELL LINE:(I) ORGANELLE:(ix) FEATURE:(A) NAME/KEY: R-ras gene product(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION:(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:MetSerSerGlyAlaAlaSerGlyThrGlyArgGlyArg510ProArgGlyGlyGlyProGlyProGlyAspProProPro152025SerGluThrHisLysLeuValValValGlyGlyXaaGly3035ValGlyLysSerAlaLeuThrIleGlnPheIleGlnSer404550TyrPheValSerAspTyrAspProThrIleGluAspSer556065TyrThrLysIleCysSerValAspGlyIleProAlaArg7075LeuAspIleLeuAspThrAlaGlyXaaGluGluPheGly808590AlaMetArgGluGlnTyrMetArgAlaGlyHisGlyPhe95100LeuLeuValPheAlaIleAsnAspArgGlnSerPheAsn105110115GluValGlyLysLeuPheThrGlnIleLeuArgValLys120125130AspArgAspAspPheProValValLeuValGlyAsnLys135140AlaAspLeuGluSerGlnArgGlnValProArgSerGlu145150155AlaSerAlaPheGlyAlaSerHisHisValAlaTyrPhe160165GluAlaSerAlaLysLeuArgLeuAsnValAspGluAla170175180PheGluGlnLeuValArgAlaValArgLysTyrGlnGlu185190195GlnGluLeuProProSerProProSerAlaProArgLys200205LysGlyGlyGlyCysProCysValLeuLeu210215(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 204(B) TYPE: Amino acid(C) STRANDEDNESS: Single(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: Protein(iii) HYPOTHETICAL: No(vi) ORIGINAL SOURCE:(A) ORGANISM: Human(B) STRAIN:(C) INDIVIDUAL ISOLATE:(D) DEVELOPMENTAL STAGE:(E) HAPLOTYPE:(F) TISSUE TYPE:(G) CELL TYPE:(H) CELL LINE:(I) ORGANELLE:(ix) FEATURE:(A) NAME/KEY: TC21 gene product(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION:(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:MetAlaAlaAlaGlyTrpArgAspGlySerGlyGlnGlu1510LysTyrArgLeuValValValGlyGlyXaaGlyValGly152025LysSerAlaLeuThrIleGlnPheIleGlnSerTyrPhe3035ValThrAspTyrAspProThrIleGluAspSerTyrThr404550LysGlnCysValIleAspAspArgAlaAlaArgLeuAsp556065IleLeuAspThrAlaGlyXaaGluGluPheGlyAlaMet7075ArgGluGlnTyrMetArgThrGlyGluGlyPheLeuLeu808590ValPheSerValThrAspArgGlySerPheGluGluIle95100TyrLysPheGlnArgGlnIleLeuArgValLysAspArg105110115AspGluPheProMetIleLeuIleGlyAsnLysAlaAsp120125130LeuAspHisGlnArgGlnValThrGlnGluGluGlyGln135140GlnLeuAlaArgGlnLeuLysValThrTyrMetGluAla145150155SerAlaLysIleArgMetAsnValAspGlnAlaPheHis160165GluLeuValArgValIleArgLysPheGlnGluGlnGlu170175180CysProProSerProGluProThrArgLysGluLysAsp185190195LysLysGlyCysHisCysValIlePhe200(2) INFORMATION FOR SEQ ID NO:5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 615(B) TYPE: Nucleic acid(C) STRANDEDNESS: Double(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: cDNA(iii) HYPOTHETICAL: No(vi) ORIGINAL SOURCE:(A) ORGANISM: Human(B) STRAIN:(C) INDIVIDUAL ISOLATE:(D) DEVELOPMENTAL STAGE:(E) HAPLOTYPE:(F) TISSUE TYPE:(G) CELL TYPE:(H) CELL LINE:(I) ORGANELLE:(ix) FEATURE:(A) NAME/KEY: TC21 gene(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION:(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:ATGGCCGCGGCCGGCTGGCGGGACGGCTCCGGCCAGGAGA40AGTACCGGCTCGTGGTGGTCGGCGGGGGCGGCGTGGGCAA80GTCGGCGCTCACCATCCAGTTCATCCAGTCCTATTTTGTA120ACGGATTATGATCCAACCATTGAAGATTCTTACACAAAGC160AGTGTGTGATAGATGACAGAGCAGCCCGGCTAGATATTTT200GGATACAGCAGGANNNGAAGAGTTTGGAGCCATGAGAGAA240CAGTATATGAGGACTGGCGAAGGCTTCCTGTTGGTCTTTT280CAGTCACAGATAGAGGCAGTTTTGAAGAAATCTATAAGTT320TCAAAGACAGATTCTCAGAGTAAAGGATCGTGATGAGTTC360CCAATGATTTTAATTGGTAATAAAGCAGATCTGGATCATC400AAAGACAGGTAACACAGGAAGAAGGACAACAGTTAGCACG440GCAGCTTAAGGTAACATACATGGAGGCATCAGCAAAGATT480AGGATGAATGTAGATCAAGCTTTCCATGAACTTGTCCGGG520TTATCAGGAAATTTCAAGAGCAGGAATGTCCTCCTTCACC560AGAACCAACACGGAAAGAAAAAGACAAGAAAGGCTGCCAT600TGTGTCATTTTCTAG615(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 24(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY: primer A(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION:(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:ATAGATGACAGAGCAGCCCGGCTA24(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 24(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY: primer B(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION:(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:GATAGAGGCAGTTTTGAAGAAATC24(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 31(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY: p5(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: BamH1-tagged (+)primer(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:AAAGGATCCATGAGCAGCGGGGCGGCGTCCG31(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 30(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY: p10(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: EcoR1-tagged (-)primer(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:AAAGAATTCCTACAGCAGGACGCAGGGGCA30(2) INFORMATION FOR SEQ ID NO:10:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 25(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY:(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: position 38complementary mutant oligonucleotide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:TCGTGGGCGGCGTCGGCGTGGGCAA25(2) INFORMATION FOR SEQ ID NO:11:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 24(B) TYPE: Nucleic acid(C) STRANDEDNESS: Unknown(D) TOPOLOGY: Unknown(ii) MOLECULE TYPE: oligonucleotide(iii) HYPOTHETICAL: No(ix) FEATURE:(A) NAME/KEY:(B) LOCATION:(C) IDENTIFICATION METHOD:(D) OTHER INFORMATION: position 87complementary mutant oligonucleotide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:GACACCGCGGGCCTGGAAGAGTTC24__________________________________________________________________________ | The oncogene of the present invention, isolated by expression cloning from a human ovarian cancer is a mutant of TC21. The present invention teaches that ras-related genes not thought to have transforming potential can contribute importantly to cancers which have been refractory to oncogene detection. The present invention teaches that another ras relative gene, R-ras, which was previously reported to lack transforming potential, has transforming capacity as well. Thus, these and other genes similarly related to prototype and activated by analogous mechanisms may be important in the diagnosis and prognosis of certain cancers, as well as be critical in the design of rational approaches to therapy of cancers in which they play a role. | 2 |
FIELD OF INVENTION
[0001] The present invention relates to a method for classification of cancer in an individual, wherein the microsatellite status and a prognostic marker are determined by examining gene expression patterns. The invention also relates to various methods of treatment of cancer. Additionally, the present invention concerns a pharmaceutical composition for treatment of cancer and uses of the present invention. The invention also relates to an assay for classification of cancer.
BACKGROUND OF INVENTION
[0002] Studies of differential gene expression in diseased and normal tissues have been greatly facilitated by the building of large databases of the human genome sequences. Gene expression alterations are important factors in the progression from normal tissue to diseased tissue. In order to obtain a profile of transcriptional status in a certain cell type or tissue, array-based screening of thousands of genes simultaneously is an invaluable tool. Array-based screening even allows for the identification of key genes that alone, or in combination with other genes, regulate the behaviour of a cell or tissue. Candidate genes for future therapeutic intervention may thus also be identified.
[0003] Colorectal cancer generally occurs in 1 out of every 20 individuals at some point during their lifetime. In the United States alone about 150,000 new cases are diagnosed each year which amount to 15% of the total number of new cancer diagnoses. Unfortunately, colorectal cancer causes about 56,000 deaths a year in the United States.
[0004] The malignant transformation from normal tissue to cancer is believed to be a multistep process. Two molecular pathways are known to be involved in the development of colorectal cancer (Lengauer C, Kinzler K W, Vogelstein B., 1998) namely the microsatellite stable (MSS) pathway and the microsatellite instable (MSI) pathway. MSS is associated with high frequency of allelic losses, abnormalities of cytogenetic nature and abnormal tumor content of DNA. MSI however is associated with defects in the DNA mismatch repair system which leads to increased rate of point mutations and minor chromosomal insertions or deletions.
[0005] MSI tumors can be of hereditary or sporadic nature. Ninety percent of MSI tumours are of sporadic origin. Sporadic tumours are presumably MSI due to epigenetic hypermethylation of the MLH1 gene promoter. The hereditary tumours account for 10% of the MSI tumors. Mutations of for example the MLH1 or MSH 2 genes are often the cause of hereditary tumor development.
[0006] The ability of being able to determine the sporadic or hereditary nature of a MSI tumor is highly valuable. In case a tumor is characterized as being MSI, and certain clinical criteria are fulfilled such as age below 50 or three first degree relatives with colon cancer, a screening programme of family members for early diagnosis and treatment of potential colon or endometrial cancer development is initiated. The human and economic costs in relation to screening programmes are severe. Consequently, a need for identifying colon cancers with a hereditary character exists. Further, these patients have a poor prognosis, as they have an increased risk of metachronous colon tumors and a highly increased risk of getting cancer in the endometrium (females), upper urinary tract and a number of other organs. Thus, one may regard the determination of a colon tumor as being sporadic or hereditary as determination of a prognostic factor.
[0007] Tumors appearing to be similar—morphologically, histochemically or microscopically—can be profoundly different. They can have different invasive and metastasizing properties, as well as respond differently to therapy. There is thus a need in the art for methods which distinguish tumors and tissues on different bases than are currently in use in the clinic. Determination of microsatellite status using an array-based methodology is faster than conventional DNA based methods, as it does not require microdissection, and forms a set of genes that can be combined with other sets of genes on a colon cancer array that can be used to determine microsatellite status as well as e.g. predict disease course by identifying hereditary cases or other prognostic important factors, and finally predict therapy response.
SUMMARY OF INVENTION
[0008] In one aspect the present invention relates to a method of classifying cancer in an individual having contracted cancer comprising
[0000] in a sample from the individual having contracted cancer determining the microsatellite status of the tumor and
in a sample from the individual having contracted cancer, said sample comprising a plurality of gene expression products the presence and/or amount which forms a pattern, determining from said pattern a prognostic marker, wherein the microsatellite status and the prognostic marker is determined simultaneously or sequentially
classifying said cancer from the microsatellite status and the prognostic marker.
[0009] The cancer may be any cancer known to be microsatellite instable in at least a fraction of the cases, such as colon cancer, uterine cancer, ovary cancer, stomach cancer, cancer in the small intestine, cancer in the biliary system, urinary tract cancer, brain cancer or skin cancer. These cancers are part of the spectrum of cancers that belong to the hereditary non-polyposis colon cancer syndrome, but the invention is not limited to this syndrome.
[0010] Gene expression patterns may be formed by only a few genes, but it is also a preferred embodiment that a multiplicity of genes form the expression pattern whereby information for classification of cancer can be obtained.
[0011] Furthermore, the invention relates to a method for classification of cancer in an individual having contracted cancer, wherein the microsatellite status is determined by a method comprising the steps of
[0000] in a sample from the individual having contracted cancer, said sample comprising a plurality of gene expression products the presence and/or amount of which forms a pattern that is indicative of the microsatellite status of said cancer,
determining the presence and/or amount of said gene expression products forming said pattern,
obtaining an indication of the microsatellite status of said cancer in the individual based on the step above.
[0012] Yet another aspect of the invention relates to a method for classification cancer in an individual having contracted cancer, wherein the hereditary or sporadic nature is determined by a method comprising the steps of
[0000] in a sample from the individual having contracted cancer, said sample comprising a plurality of gene expression products the presence and/or amount of which forms a pattern that is indicative of the hereditary or sporadic nature of said cancer,
determining the presence and/or amount of said gene expression products forming said pattern,
obtaining an indication of the hereditary or sporadic nature of said cancer in the individual based on the step above.
[0013] The present invention further concerns a method for treatment of an individual comprising the steps of
[0000] selecting an individual having contracted a colon cancer, wherein the microsatellite status is stable, determined according to any of the methods as defined herein
treating the individual with anti cancer drugs.
[0014] Another aspect of the present invention relates to a method for treatment of an individual comprising the steps of
[0000] selecting an individual having contracted a colon cancer, wherein the microsatellite status is instable, determined according to any of the methods as defined herein
treating the individual with anti cancer drugs.
[0015] Yet another aspect of the present invention relates to a method for reducing malignancy of a cell, said method comprising
[0000] contacting a tumor cell in question with at least one peptide expressed by at least one gene selected from genes being expressed at least two-fold higher in tumor cells than the amount expressed in said tumor cell in question.
[0016] Additionally, the present invention concerns a method for reducing malignancy of a tumor cell in question comprising,
[0000] obtaining at least one gene selected from genes being expressed at least two fold lower in tumor cells than the amount expressed in normal cells
introducing said at least one gene into the tumor cell in question in a manner allowing expression of said gene(s).
[0017] The invention also relates to a method for reducing malignancy of a cell in question, said method comprising
[0000] obtaining at least one nucleotide probe capable of hybridising with at least one gene of a tumor cell in question, said at least one gene being selected from genes being expressed in an amount at least two-fold higher in tumor cells than the amount expressed in normal cells, and
introducing said at least one nucleotide probe into the tumor cell in question in a manner allowing the probe to hybridise to the at least one gene, thereby inhibiting expression of said at least one gene.
[0018] In a further aspect the invention relates to a method for producing antibodies against an expression product of a cell from a biological tissue, said method comprising the steps of
[0000] obtaining expression product(s) from at least one gene said gene being expressed as defined herein
immunising a mammal with said expression product(s) obtaining antibodies against the expression product.
[0019] The present invention also concerns a method for treatment of an individual comprising the steps of
[0000] selecting an individual having contracted a colon cancer, wherein the microsatellite status is stable, determined according to any of the methods as defined herein
introducing at least one gene into the tumor cell in a manner allowing expression of said gene(s).
[0020] The present invention further relates to a pharmaceutical composition for the treatment of a classified cancer comprising at least one antibody as defined herein.
[0021] In yet another aspect the invention concerns a pharmaceutical composition for the treatment of a classified cancer comprising at least one polypeptide as defined herein.
[0022] Further, the invention relates to a pharmaceutical composition for the treatment of a classified cancer comprising at least one nucleic acid and/or probe as defined herein.
[0023] In an additional aspect the present invention relates to an assay for classification of cancer in an individual having contracted cancer, comprising
[0000] at least one marker capable of determining the microsatellite status in a sample and at least one marker in a sample determining the prognostic marker, wherein the microsatellite status and the prognostic marker is determined simultaneously or sequentially.
DETAILED DESCRIPTION OF THE DRAWINGS
[0024]
FIG. 1
[0025] Unsupervised Hierarchical Clustering of Colorectal Tumors Based on the 1239 Genes with the Highest Variation Across all Tumors.
[0026] The phylogenetic tree shows the spontaneous clustering of tumor samples and normal biopsies. Germline mutation indicates samples with hereditary mutations in either MLH1 or MSH2 genes. In columns referring to results of immunohistochemistry a plus indicates a positive antibody staining. Tumor location indicates right-sided or left-sided location in the colon of the tumor.
[0027]
FIG. 2
[0028] Summary of the Performance of the Microsatellite Instability Classifier Based on Microarray Data.
[0029] Panel A shows the number of classification errors as a function of the number of genes used. Panel B shows log 2 of the ratio of the distance between a tumor to the centers of the microsatellite instable group and the microsatellite stable tumors. A value of +2 indicates that the distance of a tumor to the microsatellite instable group is 4 times the distance to the microsatellite stable group. Open bars are MSI tumors and solid bars are MSS tumors. Panel C shows the result of the permutation analysis for estimation of the stability of the classifier. This was estimated by generating one hundred new classifiers based on randomly chosen datasets from the 101 tumors each consisting of 30 microsatellite stable and 25 microsatellite instable samples. In each case the classifier was tested with the remaining 46 samples. The performance for each set was evaluated and averaged over all 100 training and test sets.
[0030]
FIG. 3
[0031] Classification of MSI Tumors as Hereditary or Sporadic Cases Based on Two Genes.
[0032] Panel A shows the number of classification errors as a function of the number of genes used. In crossvalidation we found a minimum number of one error using two genes and adding more genes increased the number of errors to a maximum number of twelve. Both genes were used in at least 36 of the 37 crossvalidation loops. Panel B shows log 2 of the ratio of the distance between a tumor to the centers of the sporadic microsatellite instable group and the hereditary microsatellite instable group. Panel C shows microarray signal values for MLH1 and PIWIL1 genes for all tumors. Asterisk indicates the misclassified tumor
[0033]
FIG. 4
[0034] Classification of Microsatellite-Instability Status Based on Real-Time PCR.
[0035] Panel A shows a cluster analysis of 18 of the 101 tumors samples and 9 genes based on the microarray data and compared to real-time PCR data from same samples and genes. Dark colors indicate relative low expression and light/light grey color palette high expression. Panel B shows the result of 47 new independent samples based on PCR data from 7 of the 9 genes. Relative distances are explained in the legend to FIG. 2 . The two misclassified tumors are indicated with an asterisk. For PCR primers and hybridization probes see supplement to methods.
[0036]
FIG. 5
[0037] Kaplan-Meier estimates of crude survival among patient with Stage II and Stage III colorectal cancer according to microsatellite status of the tumor, determined by gene expression. Open triangles indicate censored samples. The patients left at risk are denoted in brackets. The P values were calculated with use of the log-rank test.
[0038]
FIG. 6
[0039] Phylogenetic tree resulting from unsupervised hierarchical clustering. Cluster analysis of colon specimens with associated clinicopathological features.
[0040]
FIG. 7
[0041] Multidimentional scaling plot showing distances between groups of tumors.
[0042]
FIG. 8
[0043] Performance of prediction of survival before and after separation in MSI-H and MSS
[0044]
FIG. 9
[0045] Performance of the classifier for identification of hereditary disease.
[0046]
FIG. 10
[0047] Kaplan Meier estimates of overall survival among patients with Dukes' B and Dukes' C colon cancer according to microsatellite-instability status of the tumor, determined by gene expression.
DETAILED DESCRIPTION OF THE INVENTION
Classification of Cancer
[0048] The present inventors have, using large-scale array-based screenings, found a pool of genes, the expression products of which may be used to classify cancer in an individual. The presence of expression products and level of expression products provides an expression pattern which is correlated to a specific status and/or prognostic marker of the cancer. Characterization of the genes or functional analysis of the gene expression products as such is not required to classify the cancer based on the present method. Thus, the expression products of the plurality of genes can be used as markers for the classification of disease.
[0049] One aspect of the present invention concerns a method for classifying cancer in an individual having contracted cancer by determining the microsatellite status and a prognostic marker in a sample. Determination of the microsatellite status and the prognostic marker may be performed simultaneously or sequentially. In one embodiment of the present invention the microsatellite status is determined. The prognostic marker is determined in a sample, wherein the presence and/or the amount of a number of gene expression products form a pattern wherefrom the prognostic marker is determined. Based on the information gathered from the microsatellite status and the prognostic marker the cancer can be classified. In a preferred embodiment the prognostic marker is the hereditary or sporadic nature of the cancer. The hereditary or sporadic nature of the cancer can be determined through a number of steps comprising determining the presence and/or amount of gene expression products forming a pattern in a sample. The sample comprises a number of gene expression products the presence and/or amount of which forms a pattern that is indicative of the hereditary or sporadic nature of the cancer. Hereby, an indication of the hereditary or sporadic nature of the cancer is obtained.
[0050] In one embodiment of the invention the microsatellite status is determined using conventional analysis of microsatellite status as described elsewhere herein.
[0051] In another embodiment of the present invention the microsatellite status is determined by gene expression patterns wherein the presence and/or the amount of the gene expression products form a pattern that is indicative of the microsatellite status.
[0052] Classification of cancer provides knowledge of the survival chances of an individual having contracted cancer. In case of cancer which according to the present invention has been classified as a hereditary cancer, screening programmes of family members to the individual having the classified cancer can be initiated. Such screening programmes can comprise conventional screening programmes employing sequencing and other methods as described elsewhere. Thus, individuals at risk of developing cancer may be identified and action taken accordingly to detect developing cancer at an early stage of the disease greatly improving the chances of successful intervention and thus survival rates.
[0053] Classification of cancer also provides insights on which sort of treatment should be offered to the individual having contracted cancer, thus providing an improved treatment response of the individual. Likewise, the individual may be spared treatment that is inefficient in treating the particular class of cancer and thus spare the individual severe side effects associated with treatment that may even not be suitable for the class of cancer.
Microsatellite Status
[0054] The use of highly variable repetitive sequences found in microsatellite regions adjacent to genes or other areas of interest may be used as markers for linkage analysis, DNA fingerprinting, or other diagnostic application.
[0055] Microsatellites are defined as loci (or regions within DNA sequences) where short sequences of DNA are repeated in tandem repeats. This means that the sequences are repeated one right after the other. The lengths of sequences used most often are di-, tri-, or tetra-nucleotides. At the same location within the genomic DNA the number of times the sequence (ex. AC) is repeated often varies between individuals, within populations, and/or between species. Due to the many repeats the microsatellites are prone to alter if there is a reduced repair of mismatches in the genome. In the present invention the traditional method of determining microsatellite status by employing microsatellite markers is replaced by determination of gene expression patterns.
[0056] An important factor in multi-step carcinogenesis is genomic instability. The development of some cancer forms is known to follow two distinct molecular routes. One route is the microsatellite stable, MSS, (and chromosomal instable pathway) which is often associated with a high frequency of allelic losses, cytogenetic abnormalities and abnormal DNA tumor contents. The second route is the microsatellite instable pathway MSI that is characterized by defects in the DNA mismatch repair system which leads to a high rate of point mutations and small chromosomal insertions and deletions. The small chromosomal insertions and deletions can be detected as mono and dinucleotide repeats (Boland C R, Thibodeau S N, Hamilton S R, et al., Cancer Res 1998; 58(22):5248-57).
[0057] One aspect of the present invention relates to the classification of cancer in an individual having contracted cancer by determining the microsatellite status and a prognostic marker. One embodiment of the invention relates to microsatellite status determined by conventional methods employing microsatellite analysis as described above. Another embodiment of the invention relates to establishing the microsatellite status by determining the presence and/or amount of gene expression products of a sample which comprises a plurality of gene expression products forming a pattern which is indicative of the microsatellite status.
[0058] The expression products of genes according to the present invention are not necessarily identical to the genes that are analysed by microsatellite markers in conventional methods of determining microsatellite status. The pattern of the gene expression products according to the present invention however correlates with information on microsatellite status that can be obtained using traditional methods.
[0059] The determination of the microsatellite status and the prognostic marker of the cancer may be performed sequentially. However, the determinations may also be performed simultaneously.
Prognostic Marker
[0060] Together with knowledge of the microsatellite status in a sample of an individual having contracted cancer a prognostic marker is employed for classifying the cancer. The prognostic marker may be any marker that provides knowledge of the cancer type when combined with knowledge of microsatellite status. Consequently the prognostic marker may provide additional information on the cancer type when the microsatellite status is stable and similarly when the microsatellite status is instable. In a preferred embodiment of the present invention the prognostic marker is the hereditary or sporadic nature of a cancer given that the microsatellite status is instable. The prognostic marker may in another embodiment be a prognostic marker for any feature or trait that provides further possibilities of classifying cancer. The prognostic marker is determined in a sample comprising a number of gene expression products wherein the presence and/or amounts of gene expression products form a pattern that is indicative of the prognostic marker.
Hereditary and Sporadic Nature of Cancer
[0061] Hereditary nonpolyposis colon cancer (HNPCC) is a hereditary cancer syndrome which carries a very high risk of colon cancer and an above-normal risk of other cancers (uterus, ovary, stomach, small intestine, biliary system, urinary tract, brain, and skin). The HNPCC syndrome is due to mutation in a gene in the DNA mismatch repair system, usually the MLH1 or MSH2 gene or less often the MSH6 or PMS2 genes. Families with HNPCC account for about 5% of all cases of colon cancer and typically have the following features (called the Amsterdam clinical criteria):
[0062] Three or more first relative family members with colorectal cancer; affected family members in two or more generations; and at least one person with colon cancer diagnosed before the age of 50.
[0063] The highest risk with HNPCC is for colon cancer. A person with HNPCC has about an 80% lifetime risk of colon cancer. Two-thirds of these tumors occur in the proximal colon. Women with HNPCC have a 20-60% lifetime risk of endometrial cancer. In HNPCC, the gastric cancer is usually intestinal-type adenocarcinoma. The ovarian cancer in HNPCC may be diagnosed before age 40. Other HNPCC-related cancers have characteristic features: the urinary tract cancers are transitional carcinoma of the ureter and renal pelvis; the small bowel cancer is most common in the duodenum and jejunum; and the most common type of brain tumor is glioblastoma. The diagnosis of HNPCC may be made on the basis of the Amsterdam clinical criteria (listed above) or on the basis of molecular genetic testing for mutations in a mismatch repair gene (MLH1, MSH2, MSH6 or PMS2). Mutations in MLH1 and MSH2 account for 90% of HNPCC. Mutations in MSH6 and PMS2 account for the rest.
[0064] HNPCC is inherited in an autosomal dominant manner. Each child of an individual with HNPCC has a 50% chance of inheriting the mutation. Most people diagnosed with HNPCC have inherited the condition from a parent. However, not all individuals with an HNPCC gene mutation have a parent who had cancer. Prenatal diagnosis for pregnancies at increased risk for HNPCC is possible.
[0065] In tumors that are microsatellite instable it is often found that the DNA mismatch repair proteins that are encoded by the MLH1 or MSH2 genes are inactivated. In case of microsatellite instable hereditary non-polyposis colorectal cancers germline mutation in MLH1 and MSH2 and somatic loss of function of the normal allele has been found to be associated with the disease.
[0066] For most sporadic MSI tumors epigenetic hypermethylation of the MLH1 promoter can be found to be associated with the cancer (Cunningham J M, Christensen E R, Tester D J, et al., Cancer Res 1998; 58(15):3455-60., Kane M F, Loda M, Gaida G M, et al., Cancer Res 1997; 57(5):808-11., Herman J G, Umar A, Polyak K, et al., Proc Natl Acad Sci USA 1998; 95(12):6870-5., Kuismanen S A, Holmberg M T, Salovaara R, de la Chapelle A, Peltomaki P., Am J Pathol 2000; 156(5):1773-9).
Forms of Cancer
[0067] Cancer leads to a change in the expression of one or more genes. The methods according to the invention may be used for classifying cancer according to the microsatellite status and/or the hereditary or sporadic nature of the cancer. Thus, the cancer may be any malignant condition in which genomic instability is involved in the development of cancer, such as cancers related to hereditary non-polyposis colorectal cancer, such as endometrial cancer, gastric cancer, small bowel cancer, ovarian cancer, kidney cancer, pelvic renal cancer or tumors of the nervous system, such as glioblastoma.
[0068] One particular form of cancer according to the present invention is that of the colon/rectum.
[0069] The cancer may be of any tumor type, such as an adenocarcinoma, a carcinoma, a teratoma, a sarcoma, and/or a lymphoma.
[0070] In relation to the gastrointestinal tract, the biological condition may also be colitis ulcerosa, Mb. Crohn, diverticulitis, adenomas.
Colorectal Tumors
[0071] The data presented herein relates to colorectal tumors and therefore the description has focused on the gene expression level as one manner of identifying genes involved in the prediction of survival in cancer tissue. The malignant progression of cancer of colon or rectum may be described using Dukes stages where normal mucosa may progress to Dukes A superficial tumors to Dukes B, slightly invasive tumors, to Dukes C that have spread to lymph nodes and finally to Dukes D that have metastasized to other organs.
[0072] The grade of a tumor can also be expressed on a scale of I-IV. The grade reflects the cytological appearance of the cells. Grade I cells are almost normal, whereas grade II cells deviate slightly from normal. Grade III appear clearly abnormal, whereas grade IV cells are highly abnormal.
[0073] The phrase colon cancer is in this application meant to be equivalent to the phrase colorectal cancer. Colon cancers may be located in the right side of the colon, the left side of the colon, the transverse part of the colon and/or in the rectum.
Samples
[0074] The samples according to the present invention may be any cancer tissue. The sample may be in a form suitable to allow analysis by the skilled artisan, such as a biopsy of the tissue, or a superficial sample scraped from the tissue. In one embodiment of the invention it is preferred that the sample is from a resected colon cancer tumor. In another embodiment the sample may be prepared by forming a suspension of cells made from the tissue. The sample may, however, also be an extract obtained from the tissue or obtained from a cell suspension made from the tissue. The sample may be fresh or frozen, or treated with chemicals.
Expression Pattern
[0075] Expression of one gene or more genes in a sample forms a pattern that is characteristic of the state of the cell. In a sample from an individual having contracted cancer a plurality of gene expression products are present. By expression pattern is meant the presence of a combination of a number of expression products and/or the amount of expression products specific for a given biological condition, such as cancer. The pattern is produced by determining the expression products of selected genes that together reveals a pattern that is indicative of the biological condition. Thus, a selection of the genes that carry information about a specific condition is developed. Selection of the genes is achieved by analyzing large numbers of genes and their expression products to find the genes that will enable the desired differentiation between various conditions, such as microsatellite status (MSS or MSI) and/or prognostic marker, such as for example the sporadic or hereditary nature of a given cancer sample. The criteria for selection of the best genes for the pattern to be indicative of given biological conditions include confidence levels i.e. how accurate are the selected genes forming an expression pattern in giving correct information of the biological condition. Thus, in one aspect of the present invention a specific pattern of gene expression profiles can be used to determine the microsatellite status in the sample. In a second aspect of the present invention the microsatellite status is determined and a specific pattern of the presence of a plurality of gene expression products and/or amount wherefrom a prognostic marker is determined.
Determination of the Microsatellite Status Employing Gene Expression Patterns
[0076] One aspect of the invention specifically relates to a method for determining the microsatellite status in a sample of an individual having contracted cancer based on determination of the expression pattern of at least two genes, such as at least three genes, such as at least four genes, such as at least 5 genes, such as at least 6 genes, such as at least 7 genes, such as at least 8 genes, such as at least 9 genes, such as at least 10 genes, such as at least 15 genes, such as at least 20 genes, such as at least 30 genes, such as at least 40 genes, such as at least 50 genes, such as at least 60 genes, such as at least 70 genes, such as at least 80 genes, such as at least 90 genes, such as at least 126 genes selected from the group of genes listed in Table 1 below
[0000]
TABLE 1
SEQ ID
Gene name
Ref seq
Gene symbol
NO.:
chemokine (C-C motif) ligand 5
NM_002985
CCL5
1
tryptophanyl-tRNA synthetase
NM_004184
WARS
2
proteasome (prosome, macropain) activator
NM_006263
PSME1
3
subunit 1 (PA28 alpha)
bone marrow stromal cell antigen 2
NM_004335
BST2
4
ubiquitin-conjugating enzyme E2L 6
NM_004223
UBE2L6
5
A kinase (PRKA) anchor protein 1
NM_003488
AKAP1
6
proteasome (prosome, macropain) activator
NM_002818
PSME2
7
subunit 2 (PA28 beta)
carcinoembryonic antigen-related cell adhesion
NM_004363
CEACAM5
8
molecule 5
FERM, RhoGEF (ARHGEF) and pleckstrin domain
NM_005766
FARP1
9
protein 1 (chondrocyte-derived)
myosin X
NM_012334
MYO10
10
heterogeneous nuclear ribonucleoprotein L
NM_001533
HNRPL
11
autocrine motility factor receptor
NM_001144
AMFR
12
dimethylarginine dimethylaminohydrolase 2
NM_013974
DDAH2
13
tumor necrosis factor, alpha-induced protein 2
NM_006291
TNFAIP2
14
mutL homolog 1, colon cancer, nonpolyposis
NM_000249
MLH1
15
type 2 ( E. coli )
thymidylate synthetase
NM_001071
TYMS
16
intercellular adhesion molecule 1 (CD54), human
NM_000201
ICAM1
17
rhinovirus receptor
general transcription factor IIA, 2, 12 kDa
NM_004492
GTF2A2
18
Rho-associated, coiled-coil containing protein
NM_004850
ROCK2
19
kinase 2
ATP binding protein associated with cell differentiation
NM_005783
TXNDC9
20
NCK adaptor protein 2
NM_003581
NCK2
21
phytanoyl-CoA hydroxylase (Refsum disease)
NM_006214
PHYH
22
metastais-associated gene family, member 2
NM_004739
MTA2
23
amiloride binding protein 1 (amine oxidase (copper-
NM_001091
ABP1
24
containing))
biliverdin reductase A
NM_000712
BLVRA
25
phospholipase C, beta 4
NM_000933
PLCB4
26
chemokine (C—X—C motif) ligand 9
NM_002416
CXCL9
27
purine-rich element binding protein A
NM_005859
PURA
28
quinolinate phosphoribosyltransferase (nicotinate-
NM_014298
QPRT
29
nucleotide pyrophosphorylase (carboxylating))
retinoic acid receptor responder (tazarotene
NM_004585
RARRES3
30
induced) 3
chemokine (C-C motif) ligand 4
NM_002984
CCL4
31
forkhead box O3A
NM_001455
FOXO3A
32
interferon, alpha-inducible protein (clone IFI-6-
NM_002038
G1P3
34
16)
NM_022873
123
chemokine (C—X—C motif) ligand 10
NM_001565
CXCL10
35
metallothionein 1G
NM_005950
MT1G
36
NM_005950
tumor necrosis factor receptor superfamily,
NM_000043
TNFRSF6
37
member 6
NM_152877
133
NM_152876
132
NM_152875
134
NM_152872
130
NM_152873
33
NM_152871
129
NM_152874
131
endothelial cell growth factor 1 (platelet-derived)
NM_001953
ECGF1
38
SCO cytochrome oxidase deficient homolog 2
NM_005138
SCO2
39
(yeast)
chemokine (C—X—C motif) ligand 13 (B-cell
NM_006419
CXCL13
40
chemoattractant)
Granulysin
NM_006433
GNLY
41
CD2 antigen (p50), sheep red blood cell receptor
NM_001767
CD2
42
splicing factor, arginine/serine-rich 6
NM_006275
SFRS6
43
teratocarcinoma-derived growth factor 1
NM_003212
TDGF1
44
metallothionein 1H
NM_005951
MT1H
45
cytochrome P450, family 2, subfamily B, poly-
NM_000767
CYP2B6
46
peptide 6
tumor necrosis factor (ligand) superfamily, member 9
NM_003811
TNFSF9
47
RNA binding motif protein 12
NM_006047
RBM12
48
NM_006047
heat shock 105 kDa/110 kDa protein 1
NM_006644
HSPH1
49
staufen, RNA binding protein ( Drosophila )
NM_004602
STAU
50
NM_017452
125
NM_017453
126
lymphocyte antigen 6 complex, locus G6D
NM_021246
LY6G6D
51
calcium binding protein P22
NM_007236
CHP
52
CDC14 cell division cycle 14 homolog B ( S. cerevisiae )
NM_003671
CDC14B
53
NM_033331
115
epiplakin 1
XM_372063
EPPK1
54
metallothionein 1X
NM_005952
MT1X
55
transforming growth factor, beta receptor II
NM_003242
TGFBR2
56
(70/80 kDa)
protein kinase C binding protein 1
NM_012408
PRKCBP1
57
NM_183047
124
transmembrane 4 superfamily member 6
NM_003270
TM4SF6
58
pleckstrin homology domain containing, family B
NM_021200
PLEKHB1
59
(evectins) member 1
apolipoprotein L, 1
NM_003661
APOL1
60
NM_145343
120
indoleamine-pyrrole 2,3 dioxygenase
NM_002164
INDO
61
forkhead box A2
NM_021784
FOXA2
62
granzyme H (cathepsin G-like 2, protein h-
NM_033423
GZMH
63
CCPX)
baculoviral IAP repeat-containing 3
NM_001165
BIRC3
64
Homo sapiens metallothionein 1H-like protein
AF333388
135
(Hs 382039)
KIAA0182 protein
NM_014615
KIAA0182
117
G protein-coupled receptor 56
NM_005682
GPR56
65
NM_201524
116
metallothionein 2A
NM_005953
MT2A
66
F-box only protein 21
NM_015002
FBXO21
67
erythrocyte membrane protein band 4.1-like 1
NM_012156,
EPB41L1
68
NM_012156
hypothetical protein MGC21416
NM_173834
MGC21416
69
protein O-fucosyltransferase 1
NM_015352,
POFUT1
70
NM_015352
metallothionein 1E (functional)
NM_175617
MT1E
71
troponin T1, skeletal, slow
NM_003283
TNNT1
72
chimerin (chimaerin) 2
NM_004067
CHN2
73
heterogeneous nuclear ribonucleoprotein H1 (H)
NM_005520
HNRPH1
74
ATP synthase, H+ transporting, mitochondrial F1
NM_004046
ATP5A1
75
complex, alpha subunit, isoform 1, cardiac muscle
eukaryotic translation initiation factor 5A
NM_001970
EIF5A
76
perforin 1 (pore forming protein)
NM_005041
PRF1
77
OGT(O-Glc-NAc transferase)-interacting protein
NM_014965
OIP106
78
106 KDa
DEAD (Asp-Glu-Ala-Asp) box polypeptide 27
NM_017895
DDX27
79
vacuolar protein sorting 35 (yeast)
NM_018206
VPS35
80
tripartite motif-containing 44
NM_017583
TRIM44
81
transmembrane, prostate androgen induced
NM_020182
TMEPAI
82
RNA
NM_199169
127
NM_199170
128
dynein, cytoplasmic, light polypeptide 2A
NM_014183
DNCL2A
83
NM_177953
122
leucine aminopeptidase 3
NM_015907
LAP3
84
chromosome 20 open reading frame 35
NM_018478
C20orf35
85
NM_033542
118
solute carrier family 38, member 1
NM_030674
SLC38A1
86
CGI-85 protein
NM_016028
CGI-85
87
death associated transcription factor 1
NM_022105,
DATF1
88
NM_080796
121
hepatocellular carcinoma-associated antigen
NM_018487
HCA112
89
112
sestrin 1
NM_014454
SESN1
90
hypothetical protein FLJ20315
NM_017763
FLJ20315
91
hypothetical protein FLJ20647
NM_017918
FLJ20647
92
membrane protein expressed in epithelial-like
NM_024792
CT120
93
lung adenocarcinoma
DEAD/H (Asp-Glu-Ala-Asp/His) box polypeptide
NM_014314
RIG-I
94
keratin 23 (histone deacetylase inducible)
NM_015515,
KRT23
95
UDP-N-acetyl-alpha-D-
NM_007210
GALNT6
96
galactosamine:polypeptide N-
acetylgalactosaminyltransferase 6 (GalNAc-T6)
aryl hydrocarbon receptor nuclear translocator-
NM_020183
ARNTL2
97
like 2
apobec-1 complementation factor
NM_014576,
ACF
98
NM_138932
119
hypothetical protein FLJ20232
NM_019008
FLJ20232
99
apolipoprotein L, 2
NM_030882,
APOL2
100
NM_145343
120
mitochondrial solute carrier protein
NM_016612
MSCP
101
hypothetical protein FLJ20618
NM_017903
FLJ20618
102
SET translocation (myeloid leukaemia-
NM_003011.1
SET
103
associated)
ATPase, class II, type 9a
Xm_030577.9
ATP9a
104
[0077] One embodiment of the invention concerning the determination of microsatellite status is based on the expression pattern of at least 2 genes, such as at least 3 genes, such as at least 4 genes, such as at least 5 genes, such as at least 6 genes, such as at least 7 genes, such as at least 8 genes, such as at least 9 genes, such as at least 10 genes, such as at least 15 genes, such as at least 20 genes, such as at least 25 genes selected from the group of genes listed in Table 2.
[0000] TABLE 2 SEQ ID Gene name Ref seq Gene symbol NO.: chemokine (C-C motif) ligand 5 NM_002985 CCL5 1 tryptophanyl-tRNA synthetase NM_004184 WARS 2 proteasome (prosome, macropain) activator NM_006263 PSME1 3 subunit 1 (PA28 alpha) bone marrow stromal cell antigen 2 NM_004335 BST2 4 ubiquitin-conjugating enzyme E2L 6 NM_004223 UBE2L6 5 A kinase (PRKA) anchor protein 1 NM_003488 AKAP1 6 proteasome (prosome, macropain) activator NM_002818 PSME2 7 subunit 2 (PA28 beta) carcinoembryonic antigen-related cell adhesion NM_004363 CEACAM5 8 molecule 5 FERM, RhoGEF (ARHGEF) and pleckstrin domain NM_005766 FARP1 9 protein 1 (chondrocyte-derived) myosin X NM_012334 MYO10 10 heterogeneous nuclear ribonucleoprotein L NM_001533 HNRPL 11 autocrine motility factor receptor NM_001144 AMFR 12 dimethylarginine dimethylaminohydrolase 2 NM_013974 DDAH2 13 tumor necrosis factor, alpha-induced protein 2 NM_006291 TNFAIP2 14 mutL homolog 1, colon cancer, nonpolyposis NM_000249 MLH1 15 type 2 ( E. coli ) thymidylate synthetase NM_001071 TYMS 16 intercellular adhesion molecule 1 (CD54), human NM_000201 ICAM1 17 rhinovirus receptor general transcription factor IIA, 2, 12 kDa NM_004492 GTF2A2 18 Rho-associated, coiled-coil containing protein NM_004850 ROCK2 19 kinase 2 ATP binding protein associated with cell differentiation NM_005783 APACD 20 metastais-associated gene family, member 2 NM_004739 MTA2 23 chemokine (C—X—C motif) ligand 10 NM_001565 CXCL10 35 splicing factor, arginine/serine-rich 6 NM_006275 SFRS6 43 protein kinase C binding protein 1 NM_012408 PRKCBP1 57 NM_183047 124 hepatocellular carcinoma-associated antigen NM_018487 HCA112 89 112 hypothetical protein FLJ20618 NM_017903 FLJ20618 102 SET translocation (myeloid leukaemia- NM_003011.1 SET 103 associated) ATPase, class II, type 9a Xm_030577.9 ATP9a 104
or from
[0000] TABLE 3 SEQ ID Gene name Ref seq Gene symbol NO.: heterogeneous nuclear ribonucleoprotein L NM_001533 HNRPL 11 NCK adaptor protein 2 NM_003581 NCK2 21 phytanoyl-CoA hydroxylase (Refsum disease) NM_006214 PHYH 22 metastais-associated gene family, member 2 NM_004739 MTA2 23 amiloride binding protein 1 (amine oxidase NM_001091 ABP1 24 (copper-containing)) biliverdin reductase A NM_000712 BLVRA 25 phospholipase C, beta 4 NM_000933 PLCB4 26 chemokine (C—X—C motif) ligand 9 NM_002416 CXCL9 27 purine-rich element binding protein A NM_005859 PURA 28 quinolinate phosphoribosyltransferase (nicotinate- NM_014298 QPRT 29 nucleotide pyrophosphorylase (carboxylating)) retinoic acid receptor responder (tazarotene NM_004585 RARRES3 30 induced) 3 chemokine (C-C motif) ligand 4 NM_002984 CCL4 31 forkhead box O3A NM_001455 FOXO3A 32 metallothionein 1X NM_005952 MT1X 55 interferon, alpha-inducible protein (clone IFI-6- NM_002038 G1P3 34 16) NM_022873 123 chemokine (C—X—C motif) ligand 10 NM_001565 CXCL10 35 metallothionein 1G NM_005950, MT1G 36 NM_005950 tumor necrosis factor receptor superfamily, NM_000043 TNFRSF6 37 member 6 NM_152877 133 NM_152876 132 NM_152875 134 NM_152872 130 NM_152873 33 NM_152871 129 NM_152874 131 endothelial cell growth factor 1 (platelet- NM_001953 ECGF1 38 derived) SCO cytochrome oxidase deficient homolog 2 NM_005138 SCO2 39 (yeast) chemokine (C—X—C motif) ligand 13 (B-cell NM_006419 CXCL13 40 chemoattractant) Granulysin NM_006433 GNLY 41 splicing factor, arginine/serine-rich 6 NM_006275 SFRS6 43 protein kinase C binding protein 1 NM_012408 PRKCBP1 57 NM_183047 124 hepatocellular carcinoma-associated antigen NM_018487 HCA112 89 112 hypothetical protein FLJ20618 NM_017903 FLJ20618 102 SET translocation (myeloid leukaemia- NM_003011.1 SET 103 associated) ATPase, class II, type 9a Xm_030577.9 ATP9a 104
or from
[0000] TABLE 4 SEQ ID Gene name Ref seq Gene symbol NO.: heterogeneous nuclear ribonucleoprotein L NM_001533 HNRPL 11 metastais-associated gene family, member 2 NM_004739 MTA2 23 chemokine (C—X—C motif) ligand 10 NM_001565 CXCL10 35 CD2 antigen (p50), sheep red blood cell receptor NM_001767 CD2 42 splicing factor, arginine/serine-rich 6 NM_006275 SFRS6 43 teratocarcinoma-derived growth factor 1 NM_003212 TDGF1 44 metallothionein 1H NM_005951 MT1H 45 cytochrome P450, family 2, subfamily B, poly- NM_000767 CYP2B6 46 peptide 6 tumor necrosis factor (ligand) superfamily, NM_003811 TNFSF9 47 member 9 RNA binding motif protein 12 NM_006047, RBM12 48 NM_006047 heat shock 105 kDa/110 kDa protein 1 NM_006644 HSPH1 49 staufen, RNA binding protein ( Drosophila ) NM_004602 STAU 50 NM_017452 125 NM_017453 126 lymphocyte antigen 6 complex, locus G6D NM_021246 LY6G6D 51 calcium binding protein P22 NM_007236 CHP 52 CDC14 cell division cycle 14 homolog B ( S. cerevisiae ) NM_003671 CDC14B 53 NM_033331 115 epiplakin 1 XM_372063 EPPK1 54 metallothionein 1X NM_005952 MT1X 55 transforming growth factor, beta receptor II NM_003242 TGFBR2 56 (70/80 kDa) protein kinase C binding protein 1 NM_012408 PRKCBP1 57 NM_183047 129 transmembrane 4 superfamily member 6 NM_003270 TM4SF6 58 pleckstrin homology domain containing, family NM_021200 PLEKHB1 59 B (evectins) member 1 apolipoprotein L, 1 NM_003661 APOL1 60 NM_145343 125 indoleamine-pyrrole 2,3 dioxygenase NM_002164 INDO 61 forkhead box A2 NM_021784 FOXA2 62 NM_021784 hepatocellular carcinoma-associated antigen NM_018487 HCA112 89 112 mitochondrial solute carrier protein NM_016612 MSCP 101 NM_016612 hypothetical protein FLJ20618 NM_017903 FLJ20618 102 SET translocation (myeloid leukaemia- NM_003011.1 SET 103 associated) ATPasa, class II, type 9a Xm_030577.9 ATP9a 104
or from
[0000] TABLE 5 SEQ ID Gene name Ref seq Gene symbol NO.: heterogeneous nuclear ribonucleoprotein L NM_001533 HNRPL 11 metastais-associatad gene family, member 2 NM_004739 MTA2 23 chemokine (C—X—C motif) ligand 10 NM_001565 CXCL10 35 splicing factor, arginine/serine-rich 6 NM_006275 SFRS6 43 protein kinase C binding protein 1 NM_012408 PRKCBP1 57 NM_183047 124 granzyme H (cathepsin G-like 2, protein h- NM_033423 GZMH 63 CCPX) baculoviral IAP repeat-containing 3 NM_001165 BIRC3 64 NM_001165 Homo sapiens metallothionein 1H-like protein AF333388 135 (Hs 382039) KIAA0182 protein NM_014615 KIAA0182 117 G protein-coupled receptor 56 NM_005682 GPR56 65 NM_301524 116 metallothionein 2A NM_005953 MT2A 66 F-box only protein 21 NM_015002 FBXO21 67 erythrocyte membrane protein band 4.1-like 1 NM_012156 EPB41L1 68 hypothetical protein MGC21416 NM_173834 MGC21416 69 protein O-fucosyltranaferase 1 NM_015352 POFUT1 70 metallothionein 1E (functional) NM_175617 MT1E 71 troponin T1, skeletal, slow NM_003283 TNNT1 72 chimerin (chimaerin) 2 NM_004067 CHN2 73 heterogeneous nuclear ribonucleoprotein H1 NM_005520 HNRPH1 74 (H) ATP synthase, H+ transporting, mitochondrial NM_004046 ATP5A1 75 F1 complex, alpha subunit, isoform 1, cardiac muscle eukaryotic translation initiation factor 5A NM_001970 EIF5A 76 perforin 1 (pore forming protein) NM_005041 PRF1 77 OGT(O-Glc-NAc transferase)-interacting protein NM_014965 OIP106 78 106 KDa DEAD (Asp-Glu-Ala-Asp) box polypeptide 27 NM_017895 DDX27 79 hepatocellular carcinoma-associated antigen NM_018487 HCA112 89 112 hypothetical protein FLJ20232 NM_019008 FLJ20232 99 apolipoprotein L, 2 NM_030882, APOL2 100 NM_145343 120 hypothetical protein FLJ20618 NM_017903 FLJ20618 102 SET translocation (myeloid leukaemia- NM_003011.1 SET 103 associated) ATPase, class II, type 9a Xm_030577.9 ATP9a 104
or from
[0000]
TABLE 6
SEQ ID
Gene name
Ref seq
Gene symbol
NO.:
heterogeneous nuclear ribonucleoprotein L
NM_001533
HNRPL
11
metastais-associated gene family, member 2
NM_004739
MTA2
23
chemokine (C—X—C motif) ligand 10
NM_001565
CXCL10
35
metallothionein 1G
NM_005950
MT1G
36
splicing factor, arginine/serine-rich 6
NM_006275
SFRS6
43
protein kinase C binding protein 1
NM_012408
PRKCBP1
57
NM_183047
129
vacuolar protein sorting 35 (yeast)
NM_018206
VPS35
80
tripartite motif-containing 44
NM_017583
TRIM44
81
transmembrane, prostate androgen induced
NM_020182
TMEPAI
82
RNA
NM_199169
127
NM_199170
128
dynein, cytoplasmic, light polypeptide 2A
NM_014183
DNCL2A
83
NM_177953
122
leucine aminopeptidase 3
NM_015907
LAP3
84
chromosome 20 open reading frame 35
NM_018478
C20orf35
85
NM_033542
118
solute carrier family 38, member 1
NM_030674
SLC38A1
86
CGI-85 protein
NM_016028
CGI-85
87
death associated transcription factor 1
NM_022105,
DATF1
88
NM_080796
121
hepatocellular carcinoma-associated antigen
NM_018487
HCA112
89
112
sestrin 1
NM_014454
SESN1
90
hypothetical protein FLJ20315
NM_017763
FLJ20315
91
hypothetical protein FLJ20647
NM_017918
FLJ20647
92
membrane protein expressed in epithelial-like
NM_024792
CT120
93
lung adenocarcinoma
DEAD/H (Asp-Glu-Ala-Asp/His) box polypeptide
NM_014314
RIG-I
94
keratin 23 (histone deacetylase inducible)
NM_015515
KRT23
95
UDP-N-acetyl-alpha-D-
NM_007210
GALNT6
96
galactosamine:polypeptide N-
acetylgalactosaminyltransferase 6 (GalNAc-T6)
aryl hydrocarbon receptor nuclear translocator-
NM_020183
ARNTL2
97
like 2
apobec-1 complementation factor
NM_014576
ACF
98
NM_138932
119
hypothetical protein FLJ20618
NM_017903
FLJ20618
102
SET translocation (myeloid leukaemia-
NM_003011.1
SET
103
associated)
ATPase, class II, type 9a
Xm_030577.9
ATP9a
104
[0078] Another embodiment of the invention concerning the determination of microsatellite status is based on the expression pattern of at least 2 genes, such as at least 3 genes, such as at least 4 genes, such as at least 5 genes, such as at least 6 genes, such as at least 7 genes, such as at least 8 genes, such as at least 9 genes selected from the group of genes listed in Table 7 below.
[0079] RNA purification Colon specimens were obtained fresh from surgery and were immediately snap frozen in liquid nitrogen either as was, in OCD-compound or in a SDS/guadinium thiocyanate solution. Total RNA was isolated using RNAzol (WAK-Chemie Medical) or spin column technology (Sigma) following the manufactures' instructions.
[0080] Gene expression analysis These procedures were performed at described in detail elsewhere (Dyrskødt et al). Briefly, ten μg of total RNA was used as starting material for the target preparation as described. First and second strand cDNA synthesis was performed using the SuperScript II System (Invitrogen) according to the manufacturers' instructions except using an oligo-dT primer containing a T7 RNA polymerase promoter site. Labelled aRNA was prepared using the BioArray High Yield RNA Transcript Labelling Kit (Enzo) using Biotin labelled CTP and UTP (Enzo) in the reaction together with unlabeled NTP's. Unincorporated nucleotides were removed using RNeasy columns (Qiagen). Fifteen μg of cRNA was fragmented, loading onto the Affymetrix HG_U133A probe array cartridge and hybridized for 16 h. The arrays were washed and stained in the Affymetrix Fluidics Station and scanned using a confocal laser-scanning microscope (Hewlett Packard GeneArray Scanner G2500A). The readings from the quantitative scanning were analyzed by the Affymetrix Gene Expression Analysis Software (MAS 5.0) and normalized using RMA (robust multi array normalisation, Irizarry et al. 2002) in the statistical application R. Redundant probesets (as defined form Unigene build 168) with high correlation (>0.5) over all samples were removed, which reduced the dataset to approximately 14.400 probesets. This dataset was used a source for all further calculations in this manuscript.
Unsupervised Agglomerative Hierarchical Clustering
[0081] For hierarchical cluster analysis 1239 genes with a variation across all samples greater than 0.5 were median-centred to a magnitude of 1. Samples and genes were then clustered using average linkage clustering with a modified Person correlation as similarity metric (Eisen et al., PNAS 95: 14863-14868, 1998). The cluster dendrogram was visualized with TreeView (Eisen).
Group Testing
[0082] We make a statistical test where the p-value is evaluated through permutations. For each group and gene we calculate the average and the sum of squared deviations from the average. We then sum these over the genes and the groups:
[0000]
S
1
=
∑
groups
∑
genes
(
X
ij
-
X
_
gr
(
i
)
j
)
2
[0083] This expression is calculated for joining DK with SF and MSI with MSS such that we end up with two groups. The sum of squared deviations is denoted S 2 . As a test statistic we use S 1 /S 2 . A small value indicates that there is a real reduction in the deviations when going from 2 to 4 groups and thus the groups have a real significance. To judge if a value is significantly small we use permutations. For each of the four groups left when joining DK and SF we randomly allocate the members to a pseudo DK and pseudo SF in such a way that the number of members in each group are as in the original data.
[0084] To get an understanding of this separation we performed a test to see if this is caused by few genes or if many genes are involved. For this test we calculated S 1 =Σ genes S 1 (gene) and similarly with S 2 =Σ genes S 2 (gene). For each gene j we used the test statistic S 1 (j)/S 2 (j) (Table 3).
Multidimentional Scaling
[0085] We carried out multidimentional scaling on median-centered and normalized data using CMD—scale in the statistical application R and visualized in a two-dimensional plot.
Microsatellite Status Classifier
[0086] The readings from the quantitative scanning were analyzed by the Affymetrix Gene Expression Analysis Software (MAS 5.0) and normalized using RMA (robust multi array normalisation, Irizarry et al. 2002) in the statistical application R. Redundant probesets (as defined form Unigene build 168) with high correlation (>0.5) over all samples were removed, which reduced the dataset to approximately 14.400 probesets.
[0087] The microsatellite instability status classifier was based on a dataset of 4.266 genes. These genes result from the removal of genes with a variance over all tumor samples smaller than 0.2 and genes that separate Danish from Finnish samples with a t-value numerically greater than 2. We used a normal distribution with the mean dependent on the gene and the group (MSI, MSS). For each gene, we calculated the variation between the groups and the variation within the groups to select genes with a high ratio between these. To classify a sample, we calculated the sum over the genes of the squared distance from the sample value to the group mean, standardized by the variance and assigned the sample to the nearest group. The sample to be classified was excluded when calculating group means and variances.
Estimation of Classifier Stability
[0088] We validated the performance of the classifier by permutation. One hundred datasets consisting of 30 MSS samples and 25 MSI samples were randomly chosen by permutation for training of the classifier with the remaining samples in each case being assign to a testset. Averages over the 100 data sets of the number of errors in the cross-validation of the training set and in the test set were used as a measure of the precision of the classifier.
[0089] Real-time PCR (RT-PCR). The procedures were as described (Birkenkamp-Demtroder) except that we used short LNA (Locked Nucleic Acid) enhanced probes from a Human Probe Library (Exiqon™). In short, cDNA was synthesized from single samples some of which were previously analyzed on GeneChips. Reverse transcription was performed using Superscript II RT (Invitrogen). Real-time PCR analysis was performed on selected genes using the primers (DNA Technology) and probes (Exiqon, DK) described in figure legend X. All samples were normalized to GAPDH as described previously (Birkenkamp-Demtroder et. al. Cancer Res., 62: 4352-4363, 2002).
Rebuilding of Classifier Based on Real-Time PCR
[0090] The 79 tumors samples that were not analysed by real-time PCR were transformed into log ratios using one of the tumor samples as reference and used for training of the classifier. Then 23 samples of which 18 were also analyzed on arrays were equally transformed into log ratios using the same tumor sample as above as reference and tested. The idea behind this translation is that we expect the normalized PCR values to be proportional to the normalized array values, and on a log scale this becomes an additive difference. The difference is gene specific and is therefore estimated for each gene separately. The variation obtained from the microarray data, and used in the classifier, can be used directly on the PCR platform.
Results
Hierarchical Clustering
[0091] The clinical specimens used in this study were collected in two different countries from 14 different clinics in the period 1994 to 2001. The samples were selected to keep a balanced representation of microsatellite instable (MSI) and microsatellite stable (MSS) tumors from both the right- and left-sided colon. The MSI class was represented both by sporadic MSI and hereditary MSI (HNPCC) tumors. Only Dukes' B and Dukes' C tumor samples were included were selected (table 19). Before any attempt to divide a diverse sample collection into distinct classes analyzed the data for systematic bias that may have been introduces during the experimental procedures. A fast and easy way to discover both true distinct classes as well as systematic biases in the data is to perform a hierarchical clustering.
[0092] The phylogenetic tree resulting from hierarchical clustering on 1239 genes ( FIG. 6 ) reveals that the main separating factor is microsatellite status. On the upper trunk we find two clusters represented mainly by normal biopsies (14/21) and MSS tumors (18/25), respectively. The lower trunk is divided into a MSI cluster (30/36) and a second MSS cluster (MSS2-cluster) (34/37). A closer inspection of the two MSS clusters unveil that one is dominated by Danish samples (19/25) and one by Finnish samples (26/37 check). Also, it is worth to notice that the MSI cluster contains a vast majority of Finnish samples (32/36) and that the sporadic MSI samples are interspersed among the hereditary samples. The normal biopsies cluster tight together with a slight tendency to separation according to origin. Tree normal samples cluster within the MSI cluster indicating that resection of these samples may have been to close to the tumor lesion.
[0093] Inspection of the gene cluster dendrogram shows that the two groups of MSS tumors are mainly separated by a large cluster of genes being upregulated in the Danish samples (data not shown) indicating that a systematic difference between Danish and Finnish samples.
Significance of Observed Groups
[0094] Based on these observations, we performed a series of test to evaluate if the observed separation of tumors into MSS and MSI as well as DK and SF are significant. For these tests the tumor samples were grouped into four virtual tumor-groups labelled, i.e. Danish MSI (MSI-DK), Danish MSS (MSS-DK), Finnish MSI (MSI-SF) and Finnish MSS (MSS-SF). Based on 5082 genes with a variance above 0.2, we tested if all four groups are significant or if some of the groups can be joined. We considered the two possibilities of joining DK and SF, and of joining MSI and MSS and made a statistical test where the p-value is evaluated through permutations. In 100 permutations of each group combination our test value S1/S2 is considerably smaller than in all permutation (Table 20) demonstrating a very clear separation between DK and SF and between MSI and MSS.
[0000]
TABLE 20
Permutation test of groups
Pseudo
Smaller values in
Minimum in 100
group
S1/S2 from data
100 permutations
permutations
DK-SF
0.9072795
0
0.962269
I-S
0.9166195
0
0.9583325
[0095] Such a clear distinction between groups may rely on a few highly separating genes or a general difference in the gene expression profile including many genes. For both the DK-SF and MSI-MSS the effect are caused by many genes even at very criteria, i.e. low test statistic S 1 (j)/S 2 (j) values (Table 21).
[0000]
TABLE 21
Permutation test of genes
S 1 (j)/S 2 (j)
Pseudo group
<0.6
<0.7
<0.8
<0.9
DK-SF
number of genes
36
136
522
1785
max in 100 permutations
0
0
2
225
MSI-MSS
number of genes
17
103
399
1507
max in 100 permutations
0
1
8
250
[0096] When a property is present that influences a large proportion of the genes this may obscure separation of clinical relevant features in unsupervised clustering. To visualize the effect of such properties, we calculated distances by multidimensional scaling between samples with and without of 816 genes separating DK from SF with a t-value numerically greater than 2 ( FIG. 7 ). We see an improved separation of MSI and MSS with Danish and Finnish cases mixed. The MSI-DK samples are not completely separated as they are found both between the MSI-SF and the MSS samples. (These plots are not entirely unsupervised since the groups have been used to remove gene).
Construction of an MSI-MSS Classifier
[0097] For the construction of a classifier we used the expression profiles from 97 tumors for which no ambiguity had been identified in relation to microsatellite status. The 816 genes separating DK from SF were excluded, as these would be unreliable for MS classification. We built a maximum likelihood classifier in order to select a minimum of genes giving the largest possible separation of the two groups. We tested the performance of the classifier using 1-1000 genes and found that it was stable showing 3-6 errors when using 4-400 genes. Of these 106 genes were especially suited for discrimination of MSS from MSI (table 22).
[0000]
TABLE 22
LOCUS
AFFYID
SYMBOL
LINK
OMIM
REFSEQ
GENENAME
1405_i_at
CCL5
6352
187011
NM_002985
chemokine (C-C motif) ligand 5
200628_s_at
WARS
7453
191050
NM_004184
tryptophanyl-tRNA synthetase
200814_at
PSME1
5720
600654
NM_006263
proteasome (prosome, macropain) activator subunit
1 (PA28 alpha)
201641_at
BST2
684
600534
NM_004335
bone marrow stromal cell antigen 2
201649_at
UBE2L6
9246
603890
NM_004223
ubiquitin-conjugating enzyme E2L 6
201674_s_at
AKAP1
8165
602449
NM_003488
A kinase PRKA anchor protein 1
201762_s_at
PSME2
5721
602161
NM_002818
proteasome (prosome, macropain) activator subunit
2 (PA28 beta)
201884_at
CEACAM5
1048
114890
NM_004363
carcinoembryonic antigen-related cell adhesion
molecule 5
201910_at
FARP1
10160
602654
NM_005766
FERM, RhoGEF (ARHGEF) and pleckstrin domain
protein 1 (chondrocyte-derived)
201976_s_at
MYO10
4651
601481
NM_012334
myosin X
202072_at
HNRPL
3191
603083
NM_001533
heterogeneous nuclear ribonucleoprotein L
202203_s_at
AMFR
267
603243
NM_001144
autocrine motility factor receptor
202262_x_at
DDAH2
23564
604744
NM_013974
dimethylarginine dimethylaminohydrolase 2
202510_s_at
TNFAIP2
7127
603300
NM_006291
tumor necrosis factor, alpha-induced protein 2
202520_s_at
MLH1
4292
120436
NM_000249
mutL homolog 1, colon cancer, nonpolyposis type 2
( E. coli )
202589_at
TYMS
7298
188350
NM_001071
thymidylate synthetase
202637_s_at
ICAM1
3383
147840
NM_000201
Intercellular adhesion molecule 1 (CD54), human
rhinovirus receptor
202678_at
GTF2A2
2958
600519
NM_004492
general transcription factor IIA, 2, 12 kDa
202762_at
ROCK2
9475
604002
NM_004850
Rho-associated, coiled-coil containing protein kinase 2
203008_x_at
APACD
10190
NM_005783
ATP binding protein associated with cell differentiation
203315_at
NCK2
8440
604930
NM_003581
NCK adaptor protein 2
203335_at
PHYH
5264
602026
NM_006214
phytanoyl-CoA hydroxylase (Refsum disease)
203444_s_at
MTA2
9219
603947
NM_004739
metastais-associated gene family, member 2
203559_s_at
ABP1
26
104610
NM_001091
amiloride binding protein 1 (amine oxidase (copper-
containing))
203773_x_at
BLVRA
644
109750
NM_000712
biliverdin reductase A
203896_s_at
PLCB4
5332
600810
NM_000933
phospholipase C, beta 4
203915_at
CXCL9
4283
601704
NM_002416
chemokine (C—X—C motif) ligand 9
204020_at
PURA
5813
600473
NM_005859
purine-rich element binding protein A
204044_at
QPRT
23475
606248
NM_014298
quinolinate phosphoribosyltransfarase (nicotinate-
nucleotide pyrophosphorylase (carboxylating))
204070_at
RARRES3
5920
605092
NM_004585
retinoic acid receptor responder (tazarotene induced) 3
204103_at
CCL4
6351
182284
NM_002984
chemokine (C-C motif) ligand 4
204131_s_at
FOXO3A
2309
602681
NM_001455
forkhead box O3A
204326_x_at
MT1X
4501
156359
NM_005952
metallothionein 1X
204415_at
G1P3
2537
147572
NM_002038,
interferon, alpha-inducible protein (clone IFI-6-16)
NM_022873
204533_at
CXCL10
3627
147310
NM_001565
chemokine (C—X—C motif) ligand 10
204745_x_at
MT1G
4495
156353
NM_005950,
metallothionein 1G
NM_005950
204780_s_at
TNFRSF6
355
134637
NM_000043,
tumor necrosis factor receptor superfamily, member 6
NM_152877,
NM_152876,
NM_152875,
NM_152872,
NM_152873,
NM_152871
204858_s_at
ECGF1
1890
131222
NM_001953
endothelial cell growth factor 1 (platelet-derived)
205241_at
SCO2
9997
604272
NM_005138
SCO cytochrome oxidase deficient homolog 2
(yeast)
205242_at
CXCL13
10563
605149
NM_006419
chemokine (C—X—C motif) ligand 13 (B-cell chemoat-
tractant)
205495_s_at
GNLY
10578
188855
NM_006433,
granulysin
NM_006433
205831_at
CD2
914
186990
NM_001767
CD2 antigen (p50), sheep red blood cell receptor
206108_s_at
SFRS6
6431
601944
NM_006275
splicing factor, arginine/serine-rich 6
206286_s_at
TDGF1
6997
187395
NM_003212
teratocarcinoma-derived growth factor 1
206461_x_at
MT1H
4496
156354
NM_005951
metallothionein 1H
206754_s_at
CYP2B6
1555
123930
NM_000767
cytochrome P450, family 2, subfamily B, polypeptide 6
206907_at
TNFSF9
8744
606182
NM_003811
tumor necrosis factor (ligand) superfamily, member 9
206918_s_at
RBM12
10137
607179
NM_006047,
RNA binding motif protein 12
NM_006047
206976_s_at
HSPH1
10808
NM_006644
heat shock 105 kDa/110 kDa protein 1
207320_x_at
STAU
6780
601716
NM_004602,
staufen, RNA binding protein ( Drosophila )
NM_004602,
NM_017452,
NM_017453
207457_s_at
LY6G6D
58530
606038
NM_021246
lymphocyte antigen 6 complex, locus G6D
207993_s_at
CHP
11261
606988
NM_007236
calcium binding protein P22
208022_s_at
CDC14B
8555
603505
NM_003671,
CDC14 cell division cycle 14 homolog B ( S. cerevisiae )
NM_003671,
NM_033331
208156_x_at
EPPK1
83481
epiplakin 1
208581_x_at
MT1X
4501
156359
NM_005952
metallothionein 1X
208944_at
TGFBR2
7048
190182
NM_003242
transforming growth factor, beta receptor II
(70/80 kDa)
209048_s_at
PRKCBP1
23613
NM_012408,
protein kinase C binding protein 1
NM_012408,
NM_183047
209108_at
TM4SF6
7105
300191
NM_003270
transmembrane 4 superfamily member 6
209504_s_at
PLEKHB1
58473
607651
NM_021200
pleckstrin homology domain containing, family B
(evectins) member 1
209546_s_at
APOL1
8542
603743
NM_003661,
apolipoprotein L, 1
NM_003661,
NM_145343
210029_at
INDO
3620
147435
NM_002164
indoleamine-pyrrole 2,3 dioxygenase
210103_s_at
FOXA2
3170
600288
NM_021784,
forkhead box A2
NM_021784
210321_at
GZMH
2999
116831
NM_033423
granzyme H (cathepsin G-like 2, protein h-CCPX)
210538_s_at
BIRC3
330
601721
NM_001165,
baculoviral IAP repeat-containing 3
NM_001165
211456_x_at
AF333388
212057_at
KIAA0182
23199
XM_050495
KIAA0182 protein
212070_at
GPR56
9289
604110
NM_005682
G protein-coupled receptor 56
212185_x_at
MT2A
4502
156360
NM_005953
metallothionein 2A
212229_s_at
FBXO21
23014
NM_015002,
F-box only protein 21
NM_015002
212336_at
EPB41L1
2036
602879
NM_012156,
erythrocyte membrane protein band 4,1-like 1
NM_012156
212341_at
MGC21416
286451
NM_173834
hypothetical protain MGC21416
212349_at
POFUT1
23509
607491
NM_015352,
protein O-fucosyltransferase 1
NM_015352
212859_x_at
MT1E
4493
156351
NM_175617
metallothionein 1E (functional)
213201_s_at
TNNT1
7138
191041
NM_003283,
troponin T1, skeletal, slow
NM_003283,
XM_352926
213385_at
CHN2
1124
602857
NM_004067
chimerin (chimaerin) 2
213470_s_at
HNRPH1
3187
601035
NM_005520
heterogeneous nuclear ribonucleoprotein H1 (H)
213738_s_at
ATP5A1
498
164360
NM_004046
ATP synthase, H+ transporting, mitochondrial F1
complex, alpha subunit, isoform 1, cardiac muscle
213757_at
EIF5A
1984
600187
NM_001970
eukaryotic translation initiation factor 5A
214617_at
PRF1
5551
170280
NM_005041
perforin 1 (pore forming protein)
214924_s_at
OIP106
22906
608112
NM_014965
OGT(O-Glc-NAc transferase)-interacting protein 106 KDa
215693_x_at
DDX27
55661
NM_017895
DEAD (Asp-Glu-Ala-Asp) box polypeptide 27
215780_s_at
Hs.382039
216336_x_at
AL031602
217727_x_at
VPS35
55737
606931
NM_018206
vacuolar protein sorting 35 (yeast)
217759_at
TRIM44
54765
NM_017583
tripartite motif-containing 44
217875_s_at
TMEPAI
56937
606564
NM_020182,
transmembrane, prostate androgen induced RNA
NM_020182,
NM_199169,
NM_199170
217917_s_at
DNCL2A
83658
607167
NM_014183,
dynein, cytoplasmic, light polypeptide 2A
NM_014183,
NM_177953
217933_s_at
LAP3
51056
170250
NM_015907
leucine aminopeptidase 3
218094_s_at
C20orf35
55861
NM_018478,
chromosome 20 open reading frame 35
NM_018478
218237_s_at
SLC38A1
81539
NM_030674
solute carrier family 38, member 1
218242_s_at
CGI-85
51111
NM_016028,
CGI-85 protein
NM_016028
218325_s_at
DATF1
11083
604140
NM_022105,
death associated transcription factor 1
NM_022105,
NM_080796
218345_at
HCA112
55365
NM_018487
hepatocellular carcinoma-associated antigen 112
218346_s_at
SESN1
27244
606103
NM_014454
sestrin 1
218704_at
FLJ20315
54894
NM_017763
hypothetical protein FLJ20315
218802_at
FLJ20647
55013
NM_017918
hypothetical protein FLJ20647
218898_at
CT120
79850
NM_024792
membrane protein expressed in epithelial-like lung
adenocarcinoma
218943_s_at
RIG-I
23586
NM_014314
DEAD/H (Asp-Glu-Ala-Asp/His) box polypeptide
218963_s_at
KRT23
25984
606194
NM_015515,
keratin 23 (histone deacetylase inducible)
NM_015515
219956_at
GALNT6
11226
605148
NM_007210
UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-
acetylgalactosaminyltransferase 6 (GalNAc-T6)
220658_s_at
ARNTL2
56938
NM_020183
aryl hydrocarbon receptor nuclear translocator-like 2
220951_s_at
ACF
29974
NM_014576,
apobec-1 complementation factor
NM_014576,
NM_138932
221516_s_at
FLJ20232
54471
NM_019008
hypothetical protein FLJ20232
221653_x_at
APOL2
23780
607252
NM_030882,
apolipoprotein L, 2
NM_030882
221920_s_at
MSCP
51312
NM_016612,
mitochondrial solute carrier protein
NM_016612
222244_s_at
FLJ20618
55000
NM_017903
hypothetical protein FLJ20618
[0098] The minimum of three errors was found even using only 7 genes (Table 23).
[0000]
TABLE 23
Genes used for the classification of MSS vs MSI tumors
Name
Symbol
Unigene
MSS
MSI
hepatocellular carcinoma-
HCA112
Hs.12126
1261
653
associated antigen 112
metastasis-associated 1-like 1
MTA1L1
Hs.173043
45
91
chemokine (C—X—C motif)
CXCL10
Hs.2248
104
274
ligand 10
heterogeneous nuclear
HNRPL
Hs.2730
194
630
ribonucleoprotein L
hypothetical protein FLJ20618
FLJ20618
Hs.52184
776
388
splicing factor, arginine/serine-
SFRS6
Hs.6891
74
446
rich 6
protein kinase C binding protein 1
PRKCBP1
Hs.75871
294
168
Classification of Ambiguous Samples
[0099] Application of the 7-gene classifier to the four samples showing ambiguity in the microsatellite analyses assigns all four to be microsatellite stable tumor class. Notably, all four showed expression levels of Tumor Growth Factor β induced protein (TFGBI), MLH1 and thymidylate synthase (TYMS) that are atypical for MSI tumors. Furthermore, these tumors were all from the left colon. Thus the misclassified tumors are clearly truly MSS or they belong to a yet undefined class of MSI tumors.
Stability of Classification
[0100] To estimate the stability of the classifier based on all 97 tumor samples, we generated one hundred new classifiers based on randomly chosen datasets consisting of 30 MSS and 25 MSI samples. In each case the classifiers were tested with the remaining samples. The performance for each set was evaluated and averaged over all 100 training and test sets (Table 24). The mean error rate for MSS tumors was 0.52% and 1.38% for MSI tumors. The seven genes defined above were found to be those genes that were most frequently used in the crossvalidation loop. More than 50% of the errors were related to three tumors of which two were wrongly classified in all permutation and one in 94%. The remaining errors were mainly caused by four tumors with error rates of 40-47% showing that the former three samples are truly assigned contradictory to result from the microsatellite analysis and that four samples could not be assigned with confidence too any of the classes.
[0000]
TABLE 24
Performance of the classifier
Trainings set
Test set
Errors in crossvalidation
Test errors
MSI
2.8% (n = 25, range 0-6)
1.4% (n = 10, range 0-4)
MSS
0.70% (n = 30, range 0-3)
0.52% (n = 29, range 0-2)
All
1.7% (n = 55, range 1-7)
1.9% (n = 39, range 0-5)
[0000]
TABLE 25
Sensitivity, Specificity, and Predictive Value of Test for MSS
based on the eight gene Classifier
Positive for MSS
True = (0.9948 * 29) =
False = (0.138 * 10) = 1.38
28,8492
Negative for MSS
False = (0.0052 * 29) =
True = (0.962 * 10) = 9.62
0.1508
Sensitivity
28.9507/29 = 99.5%
Specificity
9.62/10 = 96.2%
Positive predictive value
28.8492/30.2292 = 95.4%
Negative predictive value
9.62/9.7708 = 98.5%
*Based on a prevalence for MSS of 85%
Survival Classifier
[0101] Using the same classification methods described above, we build classifiers for survival based on either all samples or the above defined groups of MSI-H and MSS. As seen in FIG. 10 a distinction of patient with good prognosis (>5 year survival) from patient with bad prognosis (<5 years survival) can be achieved with higher precision and using only a fraction of the genes by first separating into MSI-H and MSS groups.
Construction of a Classifier for Sporadic Versus Hereditary Microsatellite Instable Tumors
[0102] In order to identify a gene set for identification of hereditary microsatellite instable tumors we applied 19 sporadic microsatellite instable samples and 18 microsatellite instable samples to supervised classification as described above. We found ten genes we high scored for separation of sporadic MSI-H from hereditary MSI-H tumours (Table 26). In crossvalidation we found a minimum number of one error using two genes ( FIG. 9A ) and were used in at least 36 of the 37 crossvalidation loops. The genes were: the mismatch repair gene MLH1 that show a general downregulation in sporadic disease and PIWIL1 that is lower expressed in hereditary cases ( FIG. 9B ). Using these two genes only one error occurred: a sporadic microsatellite instable was classified as hereditary. Based on T-test we performed 500 permutations to test the significance of these two genes for marker genes and found both genes highly significant with p-values <0.005.
[0000]
TABLE 26
AFFYID
SYMBOL
LOCUSLINK
OMIM
REFSEQ
AFFYDESCRIPTION
206194_at
HOXC6
3223
142972
NM_004503
Homeo box C4
214868_at
PIWIL1
9271
605571
NM_004764.2
Piwi ( Drosophila )-like 1
202520_s_at
MLH1
4292
120436
NM_000249.2
MutL ( E. coli ) homolog 1
(colon cancer, nonpoly-
posis type 2)
202517_at
CRMP1
1400
602462
NM_001313.2
Collapsin response mediator
protein 1
205453_at
HOXB2
3212
142967
NM_002145.2
Homeo box B2 (HOXB2)
217791_s_at
PYCS/ADH18A1
5832
138250
NM_002860.2
Pyrroline-5-carboxylate
synthetase (glutamate
gamma-semialdehyde
synthetase)
(/PYCS/ADH18A1)
202393_s_at
TIEG
7071
601878
NM_005655.1
TGFB inducible early
growth response (TIEG)
218803_at
CHFR
55743
605209
NM_018223.1
Checkpoint with forkhead
and ring finger domains
(CHFR)
219877_at
FLJ13842
79698
NM_024645.1
Hypothetical protein
FLJ13842 (FLJ13842)
202241_at
C8FW
10221
NM_025195.2
Phosphoprotein regulated
by mitogenic pathways
(C8FW)
Cross Platform Classification
[0103] Real time PCR was applied both to verify the array data and examine if the 7-gene classifier would also perform on this platform. We chose 23 samples of which 18 were also analyzed on arrays. The correlation between the two platforms was high (data not shown). In order to test the performance of classification using PCR data we re-build our classifier with a 79 samples array dataset including only those tumors that were not analyzed with PCR. Two samples were classified in discordance with the microsatellite instability test of which one of them was ambiguously classified by the 7-gene array classifier.
Relation Between Microsatellite-Instability Status, Stage and Survival
[0104] Based on the 7-gene classifier, classification of 36 patients with Dukes' B tumors receiving no adjuvant chemotherapy, 18 were classified as MSI tumors and 18 as MSS tumors. The overall survival was highly significantly related to the classification since all nine patients that died within five years of follow-up were belonged to the MSS group (P=0.0014) ( FIG. 10A ). Thus, the 7-gene classifier clearly proved to be a strong predictor of survival in Dukes B and it can be used to select patients who need adjuvant chemotherapy, namely those classified as MSS.
[0105] Among 65 patients with Dukes' C tumors receiving adjuvant chemotherapy, 17 were classified as MSI tumors and as 48 MSS tumors. Of these, 6 MSI and 27 MSS patients died within five years of follow-up meaning no significant difference in overall survival between these groups (P=0.55) ( FIG. 10B ). A trend was that the MSI showed a poorer short-term survival than the MSS, contrary to Dukes B patients. This difference can be attributed to the fact that a recent large study has shown that chemotherapy only benefit the MSS tumor patients, thus improving their survival to a level comparable to that which is characteristic of MSI tumor patients.
Clinical Application of the Discovery
[0106] In the clinic the 106 or less genes described can be used for predicting outcome of colorectal cancer when examined at the RNA level and also on the protein level as each gene identified is the project is transcribed to RNA that is further translated into protein. The genes can also be used determine which patient should be treated with chemotherapy as only non-microsatellite instable tumors will respond to 5-FU based therapy. Building classifiers can achieve a further stratification of patient with god and bad prognosis after stratification into microsatellite instable and stable tumors. The genes used to identify hereditary disease can be used to decide which patient should enter into sequencing analysis of mismatch repair genes.
[0107] The RNA determination can be made in any form using any method that will quantify RNA. The proteins can be measured with any method quantification method that can determine the level of proteins.
REFERENCES
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Birkenkamp-Demtroder K, Christensen L L, Olesen S H, Frederiksen C M, Laiho P, Aaltonen L A, Laurberg S, Sorensen F B, Hagemann R, ORntoft T F. Gene expression in colorectal cancer. Cancer Res. 2002 Aug. 1; 62(15):4352-63.
Boland C R, Thibodeau S N, Hamilton S R, Sidransky D, Eshleman J R, Burt R W, Meltzer S J, Rodriguez-Bigas M A, Fodde R, Ranzani G N, Srivastava S. A National Cancer Institute Workshop on Microsatellite Instability for cancer detection and familial predisposition: development of international criteria for the determination of microsatellite instability in colorectal cancer. Cancer Res. 1998 Nov. 15; 58(22):5248-57. Review.
Chapusot C, Martin L, Bouvier A M, Bonithon-Kopp C, Ecarnot-Laubriet A, Rageot D, Ponnelle T, Laurent Puig P, Faivre J, Piard F. Microsatellite instability and intratumoural heterogeneity in 100 right-sided sporadic colon carcinomas. Br J Cancer. 2002 Aug. 12; 87(4):400-4.
Dyrskjot L, Thykjaer T, Kruhoffer M, Jensen J L, Marcussen N, Hamilton-Dutoit S, Wolf H, Orntoft T F. Identifying distinct classes of bladder carcinoma using microarrays. Nat Genet. 2003 January; 33(1):90-6.
Frederiksen C M, Knudsen S, Laurberg S, Orntoft T F. Classification of Dukes' B and C colorectal cancers using expression arrays. J Cancer Res Clin Oncol. 2003 May; 129(5):263-71.
Huang J, Qi R, Quackenbush J, Dauway E, Lazaridis E, Yeatman T. Effects of ischemia on gene expression. J Surg Res. 2001 August; 99(2):222-7.
Irizarry R A, Bolstad B M, Collin F, Cope L M, Hobbs B, Speed T P. Summaries of Affymetrix GeneChip probe level data. Nucleic Acids Res. 2003 Feb. 15; 31 (4):e15.
Loukola A, Eklin K, Laiho P, Salovaara R, Kristo P, Jarvinen H, Mecklin J P, Launonen V, Aaltonen L A. Microsatellite marker analysis in screening for hereditary nonpolyposis colorectal cancer (HNPCC). Cancer Res. 2001 Jun. 1; 61(11):4545-9.
Markowitz S, Hines J D, Lutterbaugh J, Myeroff L, Mackay W, Gordon N, Rustum Y, Luna E, Kleinerman J. Mutant K-ras oncogenes in colon cancers Do not predict Patient's chemotherapy response or survival. Clin Cancer Res. 1995 April; 1(4):441-5.
Mori Y, Selaru F M, Sato F, Yin J, Simms L A, Xu Y, Olaru A, Deacu E, Wang S, Taylor J M, Young J, Leggett B, Jass J R, Abraham J M, Shibata D, Meltzer S J. The impact of microsatellite instability on the molecular phenotype of colorectal tumors. Cancer Res. 2003 Aug. 1; 63(15):4577-82.
Ribic C M, Sargent D J, Moore M J, Thibodeau S N, French A J, Goldberg R M, Hamilton S R, Laurent-Puig P, Gryfe R, Shepherd L E, Tu D, Redston M, Gallinger S. Tumor microsatellite-instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for colon cancer. N Engl J Med. 2003 Jul. 17; 349(3):247-57. | The invention discloses a method for classification of cancer in an individual having contracted cancer. The method of classification involves the determination of microsatellite status and a prognostic marker by examining gene expression patterns. The invention also relates to various methods of treatment of cancer. Additionally, the present invention concerns a pharmaceutical composition for treatment of cancer and uses of the present invention. The invention also relates to an assay for classification of cancer. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application No. 62/219,246, filed on Sep. 16, 2015, which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to measurements performed using a wearable device.
BACKGROUND
[0003] A wearable device can be worn by a person riding a bicycle. A cyclist may wish to receive a measurement or estimate of their power output and/or calories burned while they ride. One way by which power output can be measured is the installation of a power meter onto a bicycle. However, such meters require installation and may be expensive. Another method for estimating power output is to measure the cyclist's heart rate and generate an estimate of power output based on the heart rate. While inexpensive, heart rate measurements and estimation of cyclist power output based on heart rate can require significant power to operate the sensor. Another approach is to estimate power output based on distance traveled and/or speed at which that distance is traveled. However, estimation based on these quantities can be inaccurate. For example, calculating an estimate of power output based on distance traveled and/or speed at which that distance is traveled will not account for dynamically experienced resistance such as that provided by wind, or by changes in elevation during the ride.
[0004] When riding a bicycle, three main factors contribute to total energy expenditure: rolling resistance, contributed by friction of the bicycle tires against the ground; grade, contributed by the force of gravity pulling against the mass of the cyclist and bicycle; and wind resistance or drag, contributed by the force of air drag against the cyclist and bicycle moving through the atmosphere. When riding a bicycle at a constant speed, the total of these three main factors represents the major power output of the cyclist.
SUMMARY
[0005] The present disclosure relates generally to determining estimates for the resistances experienced by a cyclist and thus the total power output of the cyclist. In particular, estimates of the wind resistance experienced by a cyclist can be obtained through calibration of the effective resistance a cyclist experiences as a function of heading, and thereby separated from the effective resistance due to rolling resistance and grade. Once such estimates are obtained, the user's total power output can be more accurately tracked throughout an activity.
[0006] In order to improve estimates of the contribution of each of the three portions of total power output, and thus of total power output, a cyclist may wear a wearable device. The wearable device can include a heart rate sensor to provide a series of measurements of cyclist heart rate. The wearable device can also include motion sensors to collect data about the wearable device's position and orientation in space and to track changes to the wearable device's position and orientation over time. Accelerometers in the device may track acceleration, including high frequency variation in acceleration, and use this to detect surface type. Because a cyclist can wear the wearable device, the orientation of the device can provide information about the cyclist's body position. For example, when cycling, the cyclist's arms may be in a variety of positions, depending on the cyclist's style of riding and the type of handlebars on the bicycle. If the cyclist wears the wearable device on the cyclist's wrist, the wearable device may be able to infer the cyclist's hand position, and based on this hand position may be able to infer the cyclist's riding position and thereby provide an estimate of drag contributed by the cyclist's body (e.g., less drag when riding in a tuck or more drag when riding sitting upright.)
[0007] Combining these measurements of heart rate, position and orientation, velocity, altitude, and riding position, the cyclist's total power output and the contribution of each component of that power output may be estimated.
[0008] By estimating the relative contribution of each component to total power output, a less expensive and more power-efficient technique for providing accurate estimates of cyclist power output can be created.
[0009] Embodiments of the present disclosure include a wearable device and techniques for estimating total power output and/or the contribution of wind resistance to the total power output of a cyclist wearing the wearable device. The wearable device may be worn on a wrist, such as a watch, and it may include one or more microprocessors, a display, and a variety of sensors, such as a heart rate sensor and one or more motion sensors.
[0010] In some embodiments, the motion sensors may include, for example, an accelerometer, a gyroscope, a barometer or altimeter, a magnetometer or compass, etc. The wearable device may also include a motion coprocessor, which may be optimized for low-power, continuous motion sensing and processing.
[0011] In some embodiments, the wearable device may be capable of communicating with a companion device. The wearable device may communicate with a companion device wirelessly, e.g., via a Bluetooth connection or similar wireless communication method. The companion device may be a second mobile device, such as a phone, which may include additional sensors. The additional sensors in the companion device may include a Global Positioning System (GPS) sensor, accelerometer, gyroscope, barometer or altimeter, motion coprocessor, etc. The companion device may, for example, communicate location information based on data from the GPS sensor to the wearable device.
[0012] In some embodiments, the (first) wearable device may be capable of communicating with other wearable devices. The first wearable device may communicate with other devices wirelessly, e.g., via a Bluetooth connection or similar wireless communication method. In some embodiments, some of the other wearable devices may include different hardware or firmware and may communicate using a common inter-device protocol and implement a given application programming interface (API). The first wearable device may, for example, communicate motion data or other information to the other wearable devices. The first wearable device may also be configured to receive information in kind from the other wearable devices.
[0013] Other features and advantages will become apparent from the following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to facilitate a fuller understanding of the present disclosure, reference is now made to the accompanying drawings, in which like elements are referenced with like numerals. These drawings should not be construed as limiting the present disclosure, but are intended to be illustrative only.
[0015] FIG. 1 shows a wearable device in accordance with an embodiment of the present disclosure.
[0016] FIG. 2 depicts a block diagram of a wearable device in accordance with an embodiment of the present disclosure.
[0017] FIG. 3 shows a companion device in accordance with an embodiment of the present disclosure.
[0018] FIG. 4 shows a schematic representation of a user with a wearable device riding a bicycle in accordance with an embodiment of the present disclosure.
[0019] FIG. 5 shows the various relevant forces acting on a cyclist during a ride and the relevant velocities of the cyclist.
[0020] FIG. 6 shows a method for determining an estimate of wind resistance in accordance with an embodiment of the present disclosure.
[0021] FIG. 7 illustrates the variation of effective resistance or total cyclist power output with heading in the presence of wind.
[0022] FIG. 8A illustrates the hand position termed “tops” and associated riding position.
[0023] FIG. 8B illustrates the hand position termed “hoods” and associated riding position.
[0024] FIG. 8C illustrates the hand position termed “drops” and associated riding position.
[0025] FIG. 9 shows a method for using an accelerometer to improve estimation of C rr according to some embodiments of the present disclosure.
[0026] FIG. 10 shows a method for calculating power output in accordance with an embodiment of the present disclosure.
DESCRIPTION
[0027] The present disclosure describes a wearable device that may be configured to estimate total cyclist power output and/or the contribution of wind resistance to total cyclist power output while the wearer is riding a bicycle.
[0028] As described in the Background, three main factors contribute to total energy expenditure made by a cyclist moving at a constant speed: rolling resistance, grade, and wind resistance or drag. The total of these three main factors represents the total power output of the cyclist.
[0029] Grade resistance is a function which varies linearly with vertical ground speed, with a constant scalar that may be determined based purely on the mass of the combined cyclist and bicycle system.
[0030] Rolling resistance is also a function which varies linearly with ground speed. While calculating rolling resistance requires estimating the rolling resistance coefficient, it is a single unknown that does not vary significantly based on time or speed. The rolling resistance coefficient is a function of the tires and road conditions and is consistent for a given bicycle on a given terrain type.
[0031] However, wind resistance varies not only linearly with ground speed but also with the square of the relative velocity between the cyclist and the air around the cyclist, as well as depending on the exposed surface area and drag coefficient of the cyclist, which varies based on factors such as cyclist body size, equipment, and the cyclist riding position. Because wind resistance includes a significant number of unknowns, calculating wind resistance is difficult. In addition, wind resistance depends on the square of the relative velocity between the cyclist and the air around the cyclist, and the air around the cyclist may move in different directions and at different speeds depending on the speed and direction of the wind in the cyclist's current location. Even if local weather data including wind velocity is available (e.g., by downloading from a remote weather service), that velocity may be inaccurate for the cyclist's current position, particularly in locations like cities where streets form channels for winds and wind direction and speed may not correlate to the downloaded data.
[0032] Using a wearable device, the estimate of power output and the individual contributions of each of the three components of total power output can be improved by incorporating sensor information from the wearable device. Using this sensor information, an estimate of the contribution of each of these three components to the total power output of the cyclist can be provided, and in particular an estimate of wind resistance.
[0033] FIG. 1 shows an example of a wearable device 100 in accordance with an embodiment of the present disclosure. In some embodiments, the wearable device 100 may be any suitable wearable device, such as a watch configured to be worn around an individual's wrist. As described in more detail below, the wearable device 100 may be calibrated according to physical attributes of the individual and physical activity by the individual user who is wearing the wearable device 100 , including, for example, activity participation statistics.
[0034] FIG. 2 depicts a block diagram of example components that may be found within the wearable device 100 in accordance with an embodiment of the present disclosure. These components may include a heart rate sensing module 210 , a motion sensing module 220 , a display module 230 , and an interface module 240 .
[0035] The heart rate sensing module 210 may include or may be in communication with a heart rate sensor as previously described. The wearable device 100 can measure an individual's current heart rate from the heart rate sensor. The heart rate sensor may also be configured to determine a confidence level indicating a relative likelihood of an accuracy of a given heart rate measurement. In other embodiments, a traditional heart rate monitor may be used and may communicate with the wearable device 100 through a near field communication method (e.g., Bluetooth).
[0036] The wearable device 100 may also include the motion sensing module 220 . The motion sensing module 220 may include one or more motion sensors, such as an accelerometer or a gyroscope. In some embodiments, the accelerometer may be a three-axis, microelectromechanical system (MEMS) accelerometer, and the gyroscope may be a three-axis MEMS gyroscope. A microprocessor (not shown) or motion coprocessor (not shown) of the wearable device 100 may receive motion information from the motion sensors of the motion sensing module 220 to track acceleration, rotation, position, or orientation information of the wearable device 100 in six degrees of freedom through three-dimensional space.
[0037] In some embodiments, the motion sensing module 220 may include other types of sensors in addition to accelerometers and gyroscopes. For example, the motion sensing module 220 may include an altimeter or barometer, or other types of location sensors, such as a GPS sensor.
[0038] The wearable device 100 may also include the display module 230 . Display module 230 may be a screen, such as a crystalline (e.g., sapphire) or glass touchscreen, configured to provide output to the user as well as receive input from the user via touch. For example, display 230 may be configured to display a current heart rate or a daily average energy expenditure. Display module 230 may receive input from the user to select, for example, which information should be displayed, or whether the user is beginning a physical activity (e.g., starting a session) or ending a physical activity (e.g., ending a session), such as a running session or a cycling session. In some embodiments, the wearable device 100 may present output to the user in other ways, such as by producing sound with a speaker (not shown), and the wearable device 100 may receive input from the user in other ways, such as by receiving voice commands via a microphone (not shown).
[0039] In some embodiments, the wearable device 100 may communicate with external devices via interface module 240 , including a configuration to present output to a user or receive input from a user. Interface module 240 may be a wireless interface. The wireless interface may be a standard Bluetooth (IEEE 802.15) interface, such as Bluetooth v4.0, also known as “Bluetooth low energy.” In other embodiments, the interface may operate according to a cellphone network protocol such as LTE or a Wi-Fi (IEEE 802.11) protocol. In other embodiments, interface module 240 may include wired interfaces, such as a headphone jack or bus connector (e.g., Lightning, Thunderbolt, USB, etc.).
[0040] The wearable device 100 may be configured to communicate with a companion device 300 ( FIG. 3 ), such as a smartphone, as described in more detail herein. In some embodiments, the wearable device 100 may be configured to communicate with other external devices, such as a notebook or desktop computer, tablet, headphones, Bluetooth headset, etc.
[0041] The modules described above are examples, and embodiments of the wearable device 100 may include other modules not shown. For example, the wearable device 100 may include one or more microprocessors (not shown) for processing heart rate data, motion data, other information in the wearable device 100 , or executing instructions for firmware or apps stored in a non-transitory processor-readable medium such as a memory module (not shown). Additionally, some embodiments of the wearable device 100 may include a rechargeable battery (e.g., a lithium-ion battery), a microphone or a microphone array, one or more cameras, one or more speakers, a watchband, a crystalline (e.g., sapphire) or glass-covered scratch-resistant display, water-resistant casing or coating, etc.
[0042] FIG. 3 shows an example of a companion device 300 in accordance with an embodiment of the present disclosure. The wearable device 100 may be configured to communicate with the companion device 300 via a wired or wireless communication channel (e.g., Bluetooth, Wi-Fi, etc.). In some embodiments, the companion device 300 may be a smartphone, tablet computer, or similar portable computing device. The companion device 300 may be carried by the user, stored in the user's pocket, strapped to the user's arm with an armband or similar device, placed in a mounting device, or otherwise positioned within communicable range of the wearable device 100 .
[0043] The companion device 300 may include a variety of sensors, such as location and motion sensors (not shown). When the companion device 300 may be optionally available for communication with the wearable device 100 , the wearable device 100 may receive additional data from the companion device 300 to improve or supplement its calibration or calorimetry processes. For example, in some embodiments, the wearable device 100 may not include a GPS sensor as opposed to an alternative embodiment in which the wearable device 100 may include a GPS sensor. In the case where the wearable device 100 may not include a GPS sensor, a GPS sensor of the companion device 300 may collect GPS location information, and the wearable device 100 may receive the GPS location information via interface module 240 ( FIG. 2 ) from the companion device 300 .
[0044] In another example, the wearable device 100 may not include an altimeter or barometer, as opposed to an alternative embodiment in which the wearable device 100 may include an altimeter or barometer. In the case where the wearable device 100 may not include an altimeter or barometer, an altimeter or barometer of the companion device 300 may collect altitude or relative altitude information, and the wearable device 100 may receive the altitude or relative altitude information via interface module 240 ( FIG. 2 ) from the companion device 300 .
[0045] In another example, the wearable device 100 may receive motion data from the companion device 300 . The wearable device 100 may compare the motion data from the companion device 300 with motion data from the motion sensing module 220 of the wearable device 100 .
[0046] The wearable device may use motion data to predict a user's activity. Examples of activities may include, but are not limited to, walking, running, cycling, swimming, etc. The wearable device may also be able to predict or otherwise detect when a user is sedentary (e.g., sleeping, sitting, standing still, driving or otherwise controlling a vehicle, etc.). The wearable device may use a variety of motion data, including, in some embodiments, motion data from a companion device.
[0047] The wearable device may use a variety of heuristics, algorithms, or other techniques to predict the user's activity. The wearable device may also estimate a confidence level (e.g., percentage likelihood, degree of accuracy, etc.) associated with a particular prediction (e.g., 90% likelihood that the user is running) or predictions (e.g., 60% likelihood that the user is running and 40% likelihood that the user is walking).
[0048] FIG. 4 shows a schematic representation of a user with a wearable device riding a bicycle in accordance with an embodiment of the present disclosure. In the example of FIG. 4 , a user 410 is wearing a wearable device 420 (e.g., the wearable device 100 ) on the user's wrist. The user may be holding the handlebars 430 of the bicycle in a variety of different grips, as shown in FIGS. 8A-C . In this illustration, the user is holding the handlebars in the “tops” position. In some embodiments, the wearable device 420 may be worn on other portions of the user's body, such as the arm, finger, leg, or foot, so long as the portion of the user's body experiences motion related to the motion of the vehicle.
[0049] FIG. 5 depicts the velocities and forces acting on a user 500 riding a bicycle 510 . This includes vectors 520 , 530 , 540 , 550 , 560 , 570 , and 580 . Vector 520 represents the velocity of the bicycle with respect to the ground. Vector 530 represents the relative velocity between the cyclist and the air. Vector 540 represents the force exerted by air drag on the cyclist, while vector 550 represents the force exerted by friction on the bicycle. Vector 560 represents the force exerted by gravity on the bicycle and cyclist and vector 570 represents the force exerted by the ground on the bicycle and cyclist. Finally, vector 580 represents the force exerted by the cyclist by pedaling the bicycle. In the example of FIG. 5 , the bicycle is on relatively level terrain (relatively little or no pitch), and the direction of gravity acting on the vehicle is shown as “down,” approximately perpendicular to the road or other terrain.
[0050] As described above, the total power output of the bike can be described as the sum of three components, the rolling resistance, the grade, and the drag, as shown in Equation 1:
[0000] P bike =f rr +f grade +f drag (Eq. 1)
[0051] P bike is represented in FIG. 5 by vector 580 , f rr is represented by vector 550 , f grade is a function of vector 560 , and f drag is represented by vector 540 . All three of f rr , f grade , and f drag depend on the ground velocity of the bicycle shown by vector 520 , but only f drag exhibits dependence on the relative air velocity shown by vector 530 .
[0052] f rr represents the rolling resistance experienced by the cyclist. This portion of total power depends on the combined mass of the bike and the rider, m c , the force of gravity g, the rolling resistance coefficient C rr , and the ground velocity V g , as shown in Equation 2:
[0000] f rr =m c ·g·C rr ·V g (Eq. 2)
[0053] f grade represents the contribution of gravity to the forces experienced by the cyclist. This portion of total power depends on m c , g, V g , and the grade of the cycling surface S, as shown in Equation 3:
[0000] f grade =m c ·g·S·V g (Eq. 3)
[0054] Finally, f drag represents the wind resistance experienced by the cyclist. This portion of total power depends on V g , the exposed surface area A and drag coefficient C d , the air density ρ, and the relative velocity through air V rel , as shown in Equation 4:
[0000] f drag =1/2 ·ρ·A·C d ·V 2 rel ·V g (Eq. 4)
[0055] Some of these parameters may be measured directly or estimated directly from measured data. For example, P bike may be measured using a power meter or estimated using known techniques for calculating energy expenditure based on heart rate. Vg, S, and ρ may be determined using a GPS sensor or other positional sensor that provides altitude data and/or a barometer. Other parameters may be input by the user. m c is an example of this type of parameter. Finally, some parameters can be estimated. These parameters include C rr , A, C d , and V rel .
[0056] FIG. 6 illustrates a method for determining an estimate of wind resistance in accordance with an embodiment of the present disclosure. Upon detection in step 600 that a user is engaged in the activity where wind resistance is to be determined (for example, cycling), the method begins. In steps 610 , 620 , and 630 , position, speed, heading, altitude, and heart rate measurements are collected, for example by using GPS measurements and a heart rate sensor. These measurements are collected periodically time-stamped with the time of collection. The sampling period between collections of each of the three data points may be regularly spaced or irregularly spaced and steps 610 , 620 , and 630 need not be performed at the same time or intervals. For example, as heart rate determination may require a larger amount of energy to perform, heart rate determination may occur less frequently than collection of speed, heading, and altitude.
[0057] In step 640 , the time-stamped position, speed, and heading information may be split into straight line segments representing travel by the cyclist in an approximately straight line during the time period the segment represents. Each segment represents a distance of known length and heading traveled from one known position to a second known position between two known points in time. In some embodiments, the straight line segments are split by determining whether a cyclist's path has deviated from a straight line subsequent to the second known position in a set of candidate known positions by comparing the subsequent known position to the line defined by the first and second known positions and beginning a new straight line segment if the subsequent known position deviates from the line defined by the first and second known positions by more than a predetermined threshold. In step 650 , the position, speed, heading, and altitude measurements are used to determine the grade at that moment in time. For example, change in altitude over time with a known speed, or change in altitude between two positions on a straight line segment can be used to estimate grade. In step 660 , based on heart rate or a power meter, total power output can be determined.
[0058] In step 670 , a wind speed and direction are determined, either based on the outputs of steps 640 - 660 or by reference to an external source of information such as an online weather service. For example, wind data for the current location may be retrieved from an online weather service using a data network and the current location of the wearable device.
[0059] Alternatively, if wind data is unknown or cannot be retrieved, then wind direction and speed may be estimated. In step 670 , when estimating wind speed and direction according to embodiments of the present disclosure, total power output is determined at a variety of directional headings of the cyclist. For example, the straight line segments determined in step 640 may be used to determine the cyclist's heading during a particular period of time and total power outputs determined during that period of time are correlated to the cyclist's heading, providing a total power output at the directional heading of the straight line segment. By using multiple straight line segments with multiple directional headings that are different from one another, total power output for each of a variety of headings may be determined.
[0060] Once total power output has been determined across a variety of headings, the direction of the wind may be identified by examining the total power output data with respect to heading. Maximum power output is required when the cyclist is heading directly into the wind, while minimum power output occurs when the cyclist is riding with the wind. Because power output contributions from rolling resistance and grade are independent of wind speed, resistive forces contributed by these terms are effectively constant with respect to whether a cyclist is heading into or out of the wind once any systematic variations in grade (for example, cycling up or down a slope) according to heading are taken into account. The heading and speed of the wind can thus be estimated by fitting the total power output data at a variety of headings to a curve and determining the estimated V rel for that curve.
[0061] In step 680 , based on the outputs of steps 640 - 660 , and based on the knowledge of wind speed and direction determined in step 670 (whether estimated or directly obtained), estimates of various unknown parameters (for example, V rel , A, and C d ) and components of total resistance (rolling resistance, grade, and drag) may be calculated and may be used to replace, refine, or otherwise supplement existing methods of measuring total power output such as power meters or heart rate-based determinations.
[0062] According to embodiments of the present disclosure, when step 670 determines that no wind is present, C rr , A, and C d can be estimated based on a set of P bike measurements at various ground speeds V g (measurements with speed diversity) by solving sets of equations of the form shown in Equations 1-4. By comparing an adequate number of P bike measurements at various V g and incorporating direct measurements of other parameters, the system can solve for estimates of the unknown parameters C rr , A, and C d .
[0063] According to embodiments of the present disclosure, when step 670 determines that a wind of known speed and direction is present (e.g., if accurate wind data is available from a weather service, or via estimation of the wind), C rr , A, and C d can be estimated without any requirement for speed diversity. A measurement of P bike combined with direct measurements of other parameters allows the estimation of C rr , A, and C d .
[0064] According to embodiments of the present disclosure, once wind direction is determined (whether by estimation or directly) in step 670 , V rel , A, and C d can be estimated in step 680 by solving sets of equations of the form shown in Equations 1-4. If the drag coefficients A and C d have been previously calibrated (e.g., in a no wind or known wind situation), the estimate of wind speed can also be refined to a higher precision. Once wind speed has been estimated via this method, the known wind speed and direction method can be used to determine an estimate of rolling resistance C rr .
[0065] FIG. 7 illustrates the ideal model of total power resistance versus heading into or out of a wind out of the northwest, as well as an estimated model generated based on observed data from actual cyclists. The solid line 710 represents the ideal model, while the dotted line 720 represents the estimated model. Dots 730 represent measured power output at various headings. By fitting a curve to the measured power outputs, the estimated model may be generated and used to determine points of predicted minimum and maximum power output. These points of predicted minimum and maximum power output can be used to derive V rel .
[0066] FIGS. 8A-8C illustrate various hand positions riders may take. These positions may be termed “tops”, as shown in FIG. 8A , “hoods”, as shown in FIG. 8B , and “drops”, as shown in FIG. 8C . Each of these positions influences the body positioning of the cyclist, as shown in FIGS. 8A-8C , and thus influences the air drag by changing the exposed surface area A (and potentially by changing the drag coefficient C d ). In some embodiments of the present disclosure, a wearable device worn on the cyclist's wrist or hand may detect the cyclist's hand position. For example, a direction of gravity as experienced by the wearable device, combined with knowledge of the wrist on which the device is worn, may be used to estimate the hand position of the rider. Based on hand position, the body position of the cyclist may be estimated, and this estimate may be used to refine A and C d and/or to adjust these parameters in real-time as the cyclist's body position changes. By adjusting the air drag parameters with the cyclist's changes in body position, estimates of total power output may be made more accurate.
[0067] FIG. 9 illustrates a method for using an accelerometer to improve estimation of C rr according to some embodiments of the present disclosure. In step 900 , accelerometer data is collected at a high sampling rate. In step 910 , high frequency accelerometer data is separated from low frequency accelerometer data. In step 920 , high frequency accelerometer data is used to obtain an estimate of roughness of the riding surface and thereby provide or refine an estimate of C rr . For example, a surface generating relatively little high frequency accelerometer output is likely a smooth surface such as an asphalt road, with a lower C rr , while a surface generating more high frequency accelerometer output may be a rougher surface such as a dirt road, with a higher C rr . If the cyclist is riding on a mountain trail or similar very rough surface, significant high frequency accelerometer output may be present, signaling a very high C rr . In step 930 , the estimate of surface C rr is used to refine or replace the existing estimate of C rr .
[0068] FIG. 10 illustrates a method for calculating power output in accordance with an embodiment of the present disclosure. In step 1000 , the parameters described above with respect to FIG. 6 (e.g., C rr , V rel , A, and C d ) are obtained, for example by direct measurement or estimation, as described with respect to the steps of FIG. 6 . After obtaining these parameters, in step 1010 , heart rate measurements to estimate total power output are reduced in frequency, in order to save battery life of the wearable device. In some embodiments, heart rate measurements are reduced in frequency after the parameters have been obtained. In other embodiments, heart rate measurements are discontinued after the parameters have been obtained. In step 1020 , an estimate of total power output by the cyclist is obtained by applying the obtained parameters to Equations 1-4 without use of a heart rate measurement. By providing power output estimates without using heart rate measurements or while using them less frequently, the wearable device can accurately estimate cyclist power output without consuming as much battery power.
[0069] The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. For example, while the present embodiments are described with respect to a cyclist, a runner would also experience frictional forces, forces due to gravity, and wind resistance, and the embodiments could also be applied to a runner by one of ordinary skill in the art. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Further, although the present disclosure has been described herein in the context of at least one particular implementation in at least one particular environment for at least one particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. | Improved techniques and systems are disclosed for determining the components of resistance experienced by a wearer of a wearable device engaged in an activity such as bicycling or running. By monitoring data using the wearable device, improved estimates can be derived for various factors contributing to the resistance experienced by the user in the course of the activity. Using these improved estimates, data sampling rates may be reduced for some or all of the monitored data. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable.
BACKGROUND
This disclosure generally relates to soil sample collection and analysis, and more particularly to a soil sampler that can be operated manually or automatically.
Soil samples (usually the top 7 inches or so of the topsoil) are taken from farm fields and sent to a soil analysis lab to analyze the different soil nutrients contained in the sample. This analysis is used to determine the correct amount of nutrients to apply to farm fields. In the past, the process of collecting the soil sample was a slow tedious job done by using a hand probe. Recently some automation has been added to soil sampler equipment to remove some of the handwork, but none have significantly increased the speed of sampling. The disclosed system removes the hand labor, plus sampling time has been greatly decreased.
As an agronomist specializing in soil fertility I have noticed there is considerable variation of nutrient content as samples are taken across farm fields. The only way to be able to accurately measure this variability is to increase the number of samples being taken within a field. With the disclosed auto sampler the time required to collect the samples has been greatly reduced. We can now collect many more samples per field per hour, therefore greatly improving our ability to accurately measure the variability without increasing our labor to collect the samples. With accurate nutrient maps our customers need only apply nutrients where needed, reducing environmental risk and improving their profitability.
BRIEF SUMMARY
The driver of a small utility tractor operates the disclosed auto sampler. The operator manages the system from the cab. The task of the auto sampler is to cycle a collection knife into the soil for approximately 5 seconds collecting a soil sample; it then raises the knife out of the soil and through a series of motions places the collected soil into a marked storage container. When the sampler cycles the knife into the ground it marks the GPS location and tags the storage container identification number in a data file. Once the auto sampler has traveled a determined distance (usually 150′) away from the previous point it automatically starts the sampling task again. It repeats this task each time the auto sampler has traveled the determined distance (example: 150′). It does this repeatedly throughout the field. As the auto sampler continues to collect samples across the field, it places the samples in a storage tray until the field is completed.
Thus, disclosed is an automatic soil sampler for taking samples of topsoil that has a soil breakdown assembly that cuts a shallow furrow in the soil and moves debris to the side. Soil is collected with a sampling knife having a series of chambers adapted to receive samples of topsoil. A rotating discus is disposed opposite the soil sampling empty chambers for urging soil into the soil sampling empty chambers. A cup carrousel carries empty identified cups for receiving soil samples. A delivery assembly places one of the empty identified cups in a cup receiving station. A filling assembly connects the knife chambers carrying collected soil samples with the cup receiving station. The cups are filled with soil samples and moved into a collection station. Each filled cup has its identifier sent to memory along with the location at which the sample was taken.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and advantages of the present media and process, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
FIG. 1 is a side view of a tractor with the disclosed soil sampler mounted at its rear in a home position;
FIG. 2 is a side view like that in FIG. 2 , but with the soil sampler in its active, soil sampling position;
FIG. 3 is a close up view of the soil sampler with the protective covering removed to reveal the inside of the soil sampler in its home position;
FIG. 4 is a close up view of the soil sample like that in FIG. 3 , but with the soil sampler in it active soil sampling position;
FIG. 5 is a rear view of the soil sampler in its active soil sampling position showing the wheel soil furrowing assembly;
FIG. 6 is a rear view of the soil sampler in its active soil sampling position showing the knife soil collection assembly;
FIG. 7 is close up side view of the opposite side of the soil sampler with outer covering removed to show the cup carrousel assembly;
FIG. 8 is a rear view of the soil sampler with outer covering removed to reveal the soil collection system and cup carrousel assembly;
FIG. 9 is a sectional view taken along line 9 - 9 of FIG. 8 ;
FIG. 10 is a sectional view taken along line 10 - 10 of FIG. 8 ;
FIG. 11 is close up view of the knife assembly;
FIG. 12 is a sectional view taken along line 12 - 12 of FIG. 8 ;
FIG. 13 is a sectional view taken along line 13 - 13 of FIG. 12 ;
FIG. 14 is a sectional view taken along line 14 - 14 of FIG. 12 ;
FIG. 15 is an isometric view of a collection cup revealing the bar code on its bottom surface;
FIGS. 15A , 15 B, and 15 C are the flow chart for how the soil sampler operates;
FIG. 16 is the hydraulic schematic for the soil sampler; and
FIGS. 16A and 16B are the electrical block diagrams for the soil sampler; The drawings will be described is further detail below
DETAILED DESCRIPTION
Referring initially to FIGS. 1 and 2 , a tractor, 10 , has the disclosed soil sampler, 12 , mounted at its rear. All electrical and hydraulic power for soil sampler 12 is provided from tractor 10 . The only requirement for such mounting is that soil sampler 12 can be lowered from its home position shown in FIG. 1 to its soil sampling or active position shown in FIG. 2 and vice versa. Such lowering and raising of farm implements is common for a tractor to implement.
Soil sampler 12 has a large rotating disk, 14 , that cuts a furrow into the soil to be sampled. A set for inwardly toed teethed disks, 16 , clear a path by shoving rocks and debris aside so that relatively clean soil is confronted by a collection knife assembly, 18 , that actually takes the soil samples. A canted wheel, 20 , pushes soil towards the collection knife assembly in order for soil samples to be taken.
Referring now to FIG. 3 , all components are in their home position away from the ground. A cylinder assembly, 22 , raises and lowers collection knife assembly 18 . Rotating disk 14 and toed disks 16 , as a combined assembly, are held in place by a pivoting arm, 24 . When arm 24 is released, the combined assembly of rotating disk 14 and toed disks 16 are forced into the ground by a down force air bag in an operating condition.
FIG. 5 is a rear view of soil sampler 12 shown in FIG. 2 . Canted wheel 16 is seen in position to push soil towards collection knife assembly 18 so that such soil can be collected therewithin. Inwardly toed disks 16 can bee seen in this view also. Carrousel cup assembly, 25 , is seen in this view also with all outer metal protective box removed. It will be described in detail below, as will the soil transfer system that transfers soil from collection knife assembly 18 to a cup dispensed from carrousel cup assembly 25 . A cylinder assembly, 22 , raises and lowers collection knife assembly 18 .
In FIG. 6 , collection knife assembly 18 has been raised, while rotating disk 14 , towed disks 16 , and canted wheel 20 remain in their downward, operating position. They will be retracted upwardly subsequently.
Hydraulic controls, 28 , also are shown in FIGS. 5 , 6 , and 7 . A cup carousel motor, 40 , rotates cups in cup carousel 26 into position using an encoder 42 for proper placement, for transfer to cup mover 30 . A hydraulic motor, 44 , rotates cup mover 30 , with the position of cup mover, 30 , determined by an associated encoder, 46 . Cup carousel 26 contains, say, 200 cups with the bottom cups resting on a table, 47 . Each time a new cup is needed for a collected soil sample, cup carousel 26 rotates 18° so that a cup aligns with a hole formed in table 47 and below which is an alignment tube, 48 , through which the bottom most cup rests on the slide gate, 49 , which opens and drops the cup through the alignment tube, 48 , into the cup mover assembly 30 , such as a cup, 50 .
A second floor, 52 , retains cup mover assembly 30 . Below cup 50 is an opening formed in floor 52 and through which a bar code reader, 54 , reads a bar code, 56 , that is disposed on the outside bottom floor of cup 50 , as illustrated in FIG. 15 . Cup assembly 68 in FIG. 15 also is shown with a lid, 58 , that can be put on each cup once tractor 10 returns home from a farm field.
An air nozzle, 61 , disposed to the side of cup 50 , that is in position to rotate to receive a soil sample, blows away any loose dirt so that such loose dirt does not foul up any of the moving components. An air nozzle, 60 , blows air across bar code reader 54 to clean it off. Other nozzles, some disposed horizontally, could be supplied, nozzles, 60 and 61 being representative of such compressed air nozzles only.
Returning now to the soil sample transfer process, soil housed within the collection chambers in collection knife assembly 18 is urged into transfer tube 27 and then through a funnel, 62 , whose bottom spout empties into collection cup 50 . Again, compressed air through a nozzle, 91 is provided to clean up any loose dirt in the area of the disclosed soil sample collection system. Hydraulic cylinder assembly moves collection chamber within the knife assembly 18 back and forth, for example, twice to urge the collected soil sample into transfer tube 27 . As the soil samples are being transferred into transfer tube 27 , compressed air through a nozzle, 91 , is applied to clean out any remaining lodged soil in the collection chambers in collection knife assembly 18 .
Soil housed with in collection knife assembly 18 is transferred to transfer tube 27 in which soil falls under the influence of gravity and compressed air into a collection cup, such as a cup, 50 , (see FIG. 8 ) that is seated upon cup mover assembly 30 . A cylinder assembly, 36 , moves the transfer tube 27 from a home position, such as is depicted in FIG. 5 during soil collection, into a soil transfer position, such as is depicted in FIG. 6 , during which soil is transferred into a soil cup for later analysis. It should be pointed out that the tractor onboard GPS position is noted during soil collection and then associated with a bar code that each cup has and which will be described below. In the manual mode with an operator seated in seat assembly 14 , manually actuates the start procedure to initiate the automated steps necessary for soil samples to be taken.
Referring now to FIG. 5 , soil sampler 12 is shown in its active or soil sampling mode, a canted wheel 20 can be seen in a position to urge or push soil towards to the entry of the collection chambers housed in collection knife assembly 18 . Inwardly toed disks 16 that clear a path by shoving rocks and debris aside also are revealed in FIG. 3 . A soil capture slot, 85 , is located to one side of collection knife assembly 18 . The adjustable slot, 83 , sheers a thin sliver of soil as the soil passes the knife assembly when in the soil. This sheering action forces the soil sample to flow into the soil collection chamber, 72 - 76 , as the collection knife assembly, 18 , slices through the soil profile. Once the collection knife assembly is raised, 18 , cleanout guard opens, 84 , the transfer tube, 27 , extends, transferring the soil to the waiting cup, 50 , located in the cup mover, 30 .
Further detail on cup mover assembly 30 is revealed in FIG. 8 . In particular, the opening, 64 , below collection cup 50 is shown in phantom. A cam, 66 , of cup cam assembly 30 , is shown centrally disposed and which is rotated to take cup 50 and transfer the cup, 50 , to the fill position. When cup 50 is urged out of cup mover assembly 30 , is it pushes again the last filled cup, 50 , and out onto table 52 , the rearward portion of which defines a collection station 53 (as designated in FIGS. 3-7 ) where all filled collection cups are stored.
FIGS. 9-12 show various aspects of collection knife assembly 18 . When the knife blade is lowered 70 , it actually cuts into the soil. There are 4 soil chambers housed within knife blade assembly 18 . Each such chamber is revealed in FIG. 11 , either empty, 72 , 74 , 75 , and 76 , or filled with soil, 78 , 80 , 81 , and 82 . A clean out guard, 84 , (see also FIG. 12 ) actuates as the knife, 86 , is raised to provide an opening to extract the filled soil chambers out of the knife. A cylinder assembly, 90 , actuates the fore and aft movement of the chamber assembly, 85 . See also FIG. 14 in this regard. An air nozzle, 91 (see FIG. 12 ) blows high-pressure air into the chambers to clean them.
While all of the chambers can be combined for producing a composite of the soil at various depths where the sample is taken is illustrated in the drawings, it also is possible to separately collect in collections cups soil housed within each chamber. That would provide a soil sample at various depths in a defined location where the samples are taken. It should be understood further that the depth of collection knife assembly 18 can be set by the operator to the limits of the equipment.
It should be understood that several of the limit switches necessary for determining the completion and/or return to home of several of the moving components described above have not been shown in position in order to not overly complicate the drawings and illustrative description set forth herein, but are to be provided as is necessary, desirable, or convenient in conventional fashion.
Referring now to FIG. 16 , the generally hydraulic system is illustrated starting with the take off, 88 , from tractor 10 . Motors and hydraulic cylinders are labeled as they have been in the other figures. Solenoid valves, 92 - 100 , are to be provided in conventional fashion, as are hydraulic valves, 102 - 110 . The actual pluming of the hydraulic lines also is completed in conventional fashion.
In order to operative the soil sampling system whose components have been described above, the operator may use a Renu Controller, such as model FT4057T-E (Renu Electronics PVT Ltd, Batavia, Ill.). Such controller has 5 module slots. Slots 1 and 2 may have digital modules inserted, such as FIDD0808P having 8 digital input and output signals, while slots 3-5 can have analog modules inserted, such as FPRA0202L having 2 analog input and output signals. Such controller will be described in FIG. 15 for operation of the disclosed soil sampling system. It will be appreciated that other controllers could be used to advantage in accordance with the precepts disclosed herein.
Referring to FIG. 16A , a controller, 112 , is the Renu controller identified above having 5 slots filled with the modules identified above. As described above, controller 112 as communication ports for GPS input, 114 , and barcode reader, 116 . Controller also has a USB port for a portable memory device, 118 , for recordation of the data collected during a soil sampling run. Controller 112 also has a touchscreen display and a power supply, 120 , input. Power supply 120 has an emergency stop, 122 , and receives power from tractor 10 and outputs both a 12V signal and a 24V signal.
Each of the 5 I/O slots are represented along with their function in the indicated boxes in FIG. 15 along with associated motors, relays, solenoids, hydraulic pistons, encoders, and the like. FIG. 16B will be described in connection with the flow sheets of FIGS. 15A-C . The method of collecting soil samples using the disclosed soil sampling system starts in box 124 by moving the tractor into the field and turning on controller 112 , as represented in box 126 , by turning on power supply 120 . Controller 120 is initialized and the field to be sampled identified in box 128 . In box 130 , the cup mover is reset to home and the cup counter is reset. In box 132 , the cup dispenser is reset to home along with its corresponding counter. Both of these actions are accomplished in I/O Slot 1 where encoder signals active a motor and hydraulic valve controlled by I/O slot 3.
The 3-point hitch of tractor 10 is moved into position in box 134 , which is controller by I/P Slot 3. Decision box 136 is encountered which determines whether the 3-point hitch has fully moved into position. If not, steps 134 and 136 are repeated until the hitch is in position. At this point in box 138 , the time and date are checked and/or entered into controller 112 and the operator reminded to insert portable memory device 118 into controller 112 . In box 142 the tractor speed settings are checked and/or set and the high-pressure air (valves, cylinders, motors) turned on in box 144 . In box 146 , all controller functions are checked and/or set. Finally, in box 148 the operator polls the LED lights on controller 112 to see if they are all green. If not, the operation in box 146 is repeated until all green lights are seen.
The operation proceeds to box 150 where directions of the hydraulic cylinders are initialized. In box 152 the operator is reminder to load cups into the cup carousel 26 with the bar coded cups. A first cup is dispensed and its bar code read in box 154 and moved into position to receive dirt in box 156 .
Continuing now with FIG. 15B , the process proceeds to box 194 , where the operator checks and/or sets the time duration of soil sample collection (say, 7 sec.), the number of cycles needed for emptying the collection chambers (say, 3 cycles), and the distance between sample, and speed calibration (say, 5 . 0 ′/encoder click). In box 196 , tractor 10 is moved into the field at the first collection location. In box 198 , collection knife assembly 18 is automatically lowered for a pre-set time duration again while tractor 10 moves a set speed. In box 200 , like the manual mode, the GPS location is correlated with the cup bar code and this data uploaded to memory device 118 in box 202 . In box 204 , collection knife assembly 18 is automatically raised after the set duration has timed out if transfer tube 27 is in a retracted position. In box 206 , transfer tube 27 is automatically moved into a collection position, provided that collection knife assembly 18 is in a retracted position.
The collection chambers are retracted automatically and high-pressure air is blown across the chambers for a set time duration and this operation repeated a designated (say, 3) times in box 208 . Transfer tube 27 is automatically retracted from under the chambers in box 210 . Referring now to FIG. 15C and box 212 , the question is posed whether this is the last sample, if not the process proceeds to box 214 .
In box 214 , air is automatically blown across the bar code reader to clean it. Cup carousel 26 is automatically rotated to the next position to drop a next cup down for its barcode to be read in box 216 . The cup with the last sample is automatically moved onto floor 52 while air cleans the soil transfer area and the next dispensed cup is moved into position to receive a next soil sample in box 218 . In box 220 , the question is posed whether the sampler is in automatic or manual mode. If in automatic mode, the soil collection procedure proceeds to box 230 where the tractor is automatically moved in the field to the location of the next sample whereat the sample taking procedure automatically commences. At box 220 if the procedure is in manual mode, the procedure goes to box 232 where the tractor is manually driven at a continuous speed in the field to the next sample location. When the next sample location is reached, the operator presses ‘start’ at box 124 for the soil collection procedure to commence, as described above. Whether manual mode at box 224 or automatic mode at box 222 , the procedure returns to location “A” between boxes 196 and 198 in FIG. 15B and the soil collection procedure is executed.
In box 212 , if the last sample has been taken, the process proceeds to box 222 where the bar code reader is automatically cleaned with high-pressure air. In box 224 , the last filled cup is automatically moved onto floor 52 and the transfer area where the last filled cup just came from cleaned with high-pressure air. In box 226 , the operator must install caps on all cups, remove memory device 118 , and ship everything back to a lab for analysis. End 228 has been reached.
While the soil sample and soil sampling system have been described with reference to various embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope and essence of the disclosure. In addition, many modifications may be made to the teachings of the disclosure in order to adapt to a particular situation or material without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but that the disclosure will include all embodiments falling within the scope of the appended claims. In this application all units are in the US engineering system and all amounts and percentages are by weight, unless otherwise expressly indicated. Also, all citations referred herein are expressly incorporated herein by reference. | An automatic soil sampler for taking samples of topsoil has a soil breakdown assembly that cuts a shallow furrow in the soil and moves debris to the side. Soil is collected with a sampling knife having a series of empty chambers adapted to receive samples of topsoil. A rotating discus is disposed opposite the soil sampling empty chambers for urging soil into the soil sampling empty chambers. A cup carrousel carries empty identified cups for receiving soil samples. A delivery assembly places one of the empty identified cup in a cup receiving station. A filling assembly connects the knife chambers carrying collected soil samples with the cup receiving station. The cups are filled with soil samples in a collecting station. Each filled cup has its identifier sent to memory along with the location at which the sample was taken. | 0 |
STATEMENT OF GOVERNMENT INTEREST
[0001] This invention was developed under Contract No. N00174-00-C-0021 issued by the Defense Logistics Agency, SBIR Topic N99-114. The United States Government may have rights in this invention.
TECHNICAL FIELD
[0002] This invention relates generally to the field of chemical drills, and, more particularly, to an improved chemical drill that is capable of drilling holes in, or otherwise removing material from, a wide variety of target materials, such as ferrous and non-ferrous alloys, concrete, various ceramic materials, and the like.
BACKGROUND OF INVENTION
[0003] In civilian applications, high-speed chemical cutting is used in cutting, scarfing and lancing of oxidation-resistant materials. In steel mills, cutting is used to scarf large ingots, slabs and billets. Chemical lancing permits rapid and effective piercing of many materials that are difficult to pierce with standard hydrocarbon/oxygen flame technology. These materials include, for example, various irons and steels, firebrick, cinder block, aluminum billets, sand and metal incrustations in castings, and the like. Typical lancing applications include: (a) removal of blast furnace bosh plates, (b) removal of large iron masses (i.e., “salamanders”) that are deposited at the base of blast furnace, (c) cleaning of furnace linings, (d) furnace tapping to remove slag, (e) cleaning of soaking pits, (f) removal of ladle skulls, and (g) piercing holes in reinforced concrete walls and floors.
[0004] Underwater cutting and/or welding techniques are used in the repair of offshore platforms. These techniques have also been useful during the installation of new off-shore structures and undersea pipelines, the installation of hot taps, the repair of dock and harbor facilities, the modification of and addition to underwater structures, the repair of nuclear facilities, and still other applications. Permanent and temporary repairs to holes in ship- and barge-hulls have been performed. Hulls and pontoons of semi-submersible drill ships have also been repaired. Still other applications have included cutting of ship stems from castings, cutting reinforced concrete under water, underwater ship husbandry operations, salvage and rescue missions, and the like.
[0005] The common process used in industry for such cutting is the so-called “lance technology”. This process represents one of the oldest commercial uses of oxygen for piercing and cutting holes in hard materials. These materials include practically all ferrous metals and many other materials, such as concrete, slag, rock, and the like. Initially, such lances were simply an elongated length of hollow iron pipe connected at one end to a source of oxygen through an intermediate flow regulator.
[0006] Conventional lance technology employs the use of a steel pipe containing steel wires or rods. Oxygen is blown through the pipe at high pressure. The pipe, and the rods therewithin, are ignited at one end, and oxygen-rich gas is blown through the pipe. This oxidizes the pipe and the rods, and produces a hot flame. The discharge end of the lance is held in the cut or hole so that the cutting flame is presented at the distal end of the lance. The flame heats and burns the end of the pipe so that, as the operation proceeds, the pipe is consumed and must be periodically replaced with a new length of pipe. Only a small portion of the oxygen consumed is required by oxidation of the lance itself, but the heat of the burning lance assists the cutting. Once started, the reaction is very vigorous, and usually produces a lot of “splatter” of semi-solid highly-viscous lava-like material outwardly from the discharge end of the lance. If this material accumulates at the bottom of the hole or cut, it creates an obstacle to continued drilling or cutting.
[0007] Over the last ten years, there has been renewed interest in oxygen lance techniques, resulting in many improvements in the basic oxygen lance structure. Some of these improvements include the provision of one or more elongated rods within the lance, the mounting of the various component parts relative to each other, specialized configurations for the outer casting and inner rods, and cooperation between the inner rods when received within the outer casing. However, there are not believed to have been any changes in the basic chemistry of the lance process and technology. Iron-containing wires and tubes, and oxygen, remain the basic building blocks of known applications.
[0008] Other details of prior art lances, devices and methods are shown and described in U.S. Pat. Nos. 4,928,757, 4,889,187, 3,570,419, 5,320,174, 3,602,620, 5,575,331, 5,580,515, 3,725,156, 3,751,625, 4,477,060, 4,182,947 and 4,050,680, the aggregate disclosures of which are hereby incorporated by reference.
DISCLOSURE OF THE INVENTION
[0009] The invention relates to an improved chemical drill for converting the reaction products resulting from the cutting, drilling or piercing operation, to gaseous or very volatile products that can be easily directed away from the bottom of the hole or cut so as to not interfere with ongoing and continuous drilling or cutting operations. In effect, the hole or cut is self-cleaning. This results in the reduction or elimination of heat and mass transfer cutting resistances that were commonly present in the prior art, and, consequently, increases the possible cutting rate by a factor to about two to a factor of about four. The proposed drill particularly effective where deep holes or plunging cuts are necessary. The improved drill makes it possible to cut targets, such as concrete, reinforced concrete, ceramic plates, highly alloyed steel, aluminum blocks, laminated structure, granite and the like, that in the past presented major problems.
[0010] With parenthetical reference to the preferred embodiments disclosed herein, merely for purposes of illustration and not by way of limitation, the present invention provides an improved chemical drill ( 20 ) for removing portions (e.g., by drilling) of a target material ( 30 ). Examples of such target materials include, but are not limited to: ferrous alloys, alloys having an element selected from the group consisting of aluminum, copper, magnesium, titanium, a transition metal (i.e., titanium, niobium, zirconium, hafnium, vanadium and tantalum), tungsten, nickel, cobalt and chromium, concrete, reinforced concrete, aluminum oxide, silicon oxide, calcium oxide, brick, and ceramic materials selected from the group consisting of alumina, silica, zirconia, magnesia, silicon carbide and silicon nitride.
[0011] The improved drill broadly includes: an elongated tube ( 21 ) formed of a fuel-supplying material; a source ( 24 ) of oxidizer; a conduit ( 26 ) for establishing a controllable flow of oxidizer from said source through said tube; and a sleeve ( 28 ) formed of a material containing chlorine and/or fluorine mounted on said tube, such that, when said drill is ignited and used to remove portions of a target material, the chlorine and/or fluorine in said sleeve material will react chemically with the target material to produce volatile gaseous reaction products, which may be readily directed out of the hole or cut and thereby removing substantial resistance to heat and mass transfer within the hole or cut.
[0012] In the preferred embodiment, the sleeve is mounted on the outer surface of said tube. A plurality of wires or rods may be arranged in the tube. The sleeve material may contain polyvinyl chlorine, polytetrafluoroethylene, chlorinated polyvinyl chlorine and/or some other material(s) that will contribute chlorine and/or fluorine to the ongoing reaction. The tube may contain iron.
[0013] Accordingly, the general object ofthe invention is to provide an improved chemical drill or cutter.
[0014] Another object is to provide a chemical drill or cutter which increases the rate-of-removal of the target material by a factor of from about two to about four times that of known chemical drills.
[0015] Another object is to provide an improved high-speed chemical drill that is capable of use with a variety of target materials.
[0016] These and other objects and advantages will become apparent from the foregoing and ongoing written specification, the drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is a sketch, partly in section and partly in elevation, of the improved chemical drill, this view showing the plastic sleeve as surrounding the steel pipe lance.
[0018] [0018]FIG. 2 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nFe+(10−n)C 2 Cl 4 +20O 2 ], for the reactions of Example 1.
[0019] [0019]FIG. 3 is a plot of equilibrium concentrations (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nFe+(10−n)C 2 F 4 +20O 2 ], for the reactions of Example 1.
[0020] [0020]FIG. 4 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nTi+(10−n)C 2 Cl 14 +20O 2 ] for the reactions of Example 2.
[0021] [0021]FIG. 5 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nTi+(10−n)C2F4+20O 2 ], for the reactions of Example 2.
[0022] [0022]FIG. 6 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and sleeve combinations of [nAl+(10−n)C 2 Cl 4 +20O 2 ], for the reactions of Example 3.
[0023] [0023]FIG. 7 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nAl+(10−n)C 2 F 4 +20O 2 ], for the reactions of Example 3.
[0024] [0024]FIG. 8 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1 SiO 2 )+50O 2 +14.56Fe], for the reactions of Example 5.
[0025] [0025]FIG. 9 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1 SiO 2 )+20.01C 2 F 4 +46.3O 2 +14.56Fe], for the reactions shown in Example 5.
[0026] [0026]FIG. 10 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1SiO 2 )+20.01C 2 Cl 4 +47.302+14.56Fe], for the reactions of Example 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion ofthe entire written description of this invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof(e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.
[0028] Thermal piercing of concrete or reinforced concrete or highly alloyed steel plates is normally a difficult task. The molten lava of the target material at the tip of the lance provides substantial heat and mass transfer resistance to ongoing drilling or cutting operations. A typical product of thermal penetration of a concrete block by a thermal lance is lava composed of oxides of silicon, calcium, aluminum and iron. The melting point of this mixture, depending on the composition, is between about 1600-1800° C. The present invention is based on the principle of producing gaseous chemical reaction products, products or components that readily sublimate at low temperatures, or products or components with low boiling points, rather than highly-viscous lava, and directing these gaseous materials out of the hole or cut so as to remove their mass therefrom and to allow continuous cutting or drilling without diminution of penetration efficiency due to accumulations of lava-like materials in the hole or cut.
[0029] Several inorganic oxides react with chlorine or fluorine in the presence of carbon to form volatile chlorides or fluorides. These reactions, sometimes also called “carbochlorination” or “carbofluorination” reactions, occur with reasonable reaction rates at 800-1000° C. At temperatures above 1600° C., which are typical for a cutting torch, these reactions are very fast.
[0030] There are different sources of carbon, chlorine or fluorine that can be utilized to carry out the reaction. A source of carbon could be a carbon jacket surrounding the metallic jacket of the regular lance, a fine powder of carbon that is blown in the cutting spot, or a certain group of organic compounds that decompose at cutting-torch temperatures to elemental carbon. Lower hydrocarbons can be easily pyrolyzed at high temperatures. Lower chlorinated hydrocarbons, such as ethylene trichloride, elemental chlorine, PVC, perchlorinated PVC, or the like, can be used as a source of chlorine. Lower fluorinated hydrocarbons, such as polytetrafluoroethylene (i.e., Teflon®) or other polymers rich on fluorine, can be used as a source of fluorine. It is possible to inject these lower chlorinated or fluorinated hydrocarbons into the torch flame in a gaseous form. Polymers containing chlorine and/or fluorine can be part of the cutting lance body. For example, the body of the cutting lance can be inserted in a Teflon® tube.
[0031] After thermal ignition ofthe modified lance halogenated products are transported to the reaction spot and one or more of the following reactions may take place:
[0032] For Concrete:
SiO 2 +2C+2Cl 2 →SiCl 4 ↑+2CO↑ (1)
SiO 2 +2C+4HCl→SiCl 4 ↑+2CO↑+2H 2 ↑ (2)
SiO 2 +2C+4HF→SiF 4 ↑+2CO↑+2H 2 ↑ (3)
nSiO 2 +[—CF 2 —CF 2 —] n →nSiF 4 ↑+2nCO↑ (4)
CaO+C+Cl 2 →CaCl 2 ↑+CO↑ (5)
CaO+C+2HCl→CaCl 2 ↑+CO↑+H 2 ↑ (6)
2CaO +[—CF 2 —CF 2 —] n →2CaF 2 ↑+2CO↑ (7)
[0033] For Granite:
[0034] Any of chemical reactions (1)-(7) and one or more of the following additional reactions:
Al 2 O 3 +3C+3Cl 2 →2AlCl 3 ↑+3CO↑ (8)
Al 2 O 3 +3C+6HCl→2AlCl 3 ↑+3CO↑+3H 2 ↑ (9)
3[—CF 2 —CF 2 —] n +2nAl 2 O 3 →4nAlF 3 ↑+6nCO↑ (10)
[0035] For Iron:
2FeO+2C+3Cl 2 →FeCl 3 ↑+2CO↑ (11)
Fe 2 O 3 +3C+3Cl 2 →2FeCl 3 ↑+3CO↑ (12)
4nFeO+[—CF 2 —CF 2 —]→4nFeF 3 ↑+4nCO↑+2nC↑ (13)
2nFe 2 O 3 +[—CF 2 —CF 2 —] n →4nFeF 3 ↑+6nCO↑ (14)
[0036] For Ni- and Cr-Alloyed steel:
NiO+C+Cl 2 →NiCl 2 ↑+CO↑ (15)
2CrO 3 +6C+3Cl 2 →2CrCl 3 ↑+CO↑ (16)
2NiO+[—CF 2 —CF 2 —] n →2NiF 2 ↑+2CO↑ (17)
4nCrO 3 +3[—CF 2 —CF 2 —] n →4nCrF 6 ↑+12CO↑ (18)
[0037] In the foregoing reactions, the symbol “↑” indicates that the indicated element or compound is substantially gaseous at the reaction temperature. Persons skilled in this art will appreciate that CaCl 2 , CaF 2 , FeCl 3 , NiCl 2 , CrCl 3 , NiF 2 and CrF 6 may only be partially gaseous at the normal reaction temperatures.
Improving of Cutting Properties of a Regular Iron-Oxygen Lance
[0038] Referring now to the drawings, and, more particularly, to FIG. 1 thereof, an improved lance, generally indicated at 20 , is shown as broadly including a horizontally-elongated iron or steel tube 21 having inner and outer cylindrical surfaces 22 , 23 , respectively. This tube may be about 3 feet long, have an inside diameter of about ⅜″, and a radial wall thickness of about {fraction (1/16)}″. The rightward or proximal end of the tube is connected to a source 24 of oxygen or oxygen-rich gas through an intermediate flow regulator 25 . Thus, oxidizer may flow form source 24 to the tube via the flow regulator and a conduit, portions of which are indicated at 26 . The tube is formed of a fuel material, such as iron or a ferrous alloy. A sleeve, generally indicated at 28 , surrounds the tube. This sleeve is formed of a material that contains chlorine (e.g., polyvinyl chloride, chlorinated polyvinyl chloride, etc.) and/or fluorine (e.g., polytetrafluoroethylene). A plurality of rods or wires, severally indicated at 29 , are disposed within the tube to contribute additional reactant(s).
[0039] There are different sources of carbon for carbochlorination and carbofluorination reactions. One source of carbon could be a carbonjacket surrounding a regular commercial lance. The invention utilized a carbon tube with very thin walls, as well as layer of a graphoil surrounding the lance. The carbon serves as a focusing element. With a regular lance, the flame dissipates a lot of energy. With the carbon external shield the energy dissipation is lower. The explanation of this fact is straightforward. In a regular operation, the surrounding iron tube melts or is burned in synchronization with the flame propagation. However, with the carbon jacket, no melting occurs since the melting/sublimation point of carbon is around 4,000° C. The carbon jacket can burn in oxygen. The burning process is apparently a little bit slower than the burning of iron material. Consequently, the unreacted carbon tube serves as an opening to the hot flame. Details of the experiment can be found in Examples 4-6.
[0040] The performance of the invention was tested on steel plates of thicknesses of 0.26″ and 1.3″, respectively, and on a concrete plate 4.2″ thick. For the thin steel plate, there is no appreciable difference. This was not surprising since the heat-affected zone does not play an important role. However, with the thick plate, the difference is almost 100%.
[0041] The experiment with concrete slab revealed that there is no difference in rate of penetration of regular or focused lance. In a focused lance, the heat flux is much higher than in the regular lance. Nevertheless, the rate of penetration is almost the same. This is an experimental proof that the rate of cutting or drilling in concrete blocks is inversely related to the amount of lave-like material accumulating in the hole or cut. In other words, in a conventional lance, the rate of cutting slows as lava-like material accumulates in the hole or cut, and interferes with the continued cutting or drilling. Faster removal of such lava-like material will result in the improved performance of the torch. There appear to be several possibilities of increasing the rate of concrete blow-off: (a) higher linear velocity of the gas at the mouth of the torch, (b) lowering viscosity of the concrete melt by appropriate additions to the gas (e.g., fluorides, as the resulting eutectic mixture has a lower melting point and a lower viscosity at the cutting temperature can be expected), and (c) converting the liquid concrete to gaseous components (carbochlorination).
[0042] Supplying gaseous chlorine along with gaseous oxygen to the hot combustion zone will guarantee the presence of chlorine at the reaction site. The resulting volatile chlorides of iron, silicon, aluminum and calcium will evaporate from the hot spot, and therefore the heat and mass transfer will be much higher. In addition, rebar (e.g., ferrous reinforcing rod) in the concrete structure will not represent an obstacle, but rather increase the rate of penetration.
EXAMPLE 1
[0043] Combustion in an “Iron-Chlorinated/Fluorinated Polymer-Oxygen” System
[0044] The combustion system consists of a steel tube, a chlorinated/fluorinated polymer sleeve, and an excess of oxygen. The adiabatic temperature, evaluated from thermodynamic calculations, indicates that the combustion temperature in systems with chlorine or fluorine is always higher than in systems with oxygen alone. A typical difference amounts to 250-500° C.
[0045] The dependence of adiabatic temperature on the composition of the mixture is given in FIG. 2. FIG. 2 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nFe+(10−n)C 2 Cl 4 +20O 2 ], for the reactions of Example 1. This figure shows that for concentrations of less than about 6 moles, the reaction products Fe+FeCl+FeCl 2 +FeCl 3 +FeO+Fe 2 Cl 14 are substantially gaseous, and that the reaction temperatures are between about 2250-2650° K.
[0046] The composition of the combustion products is reported in FIG. 3. FIG. 3 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nFe+(10−n)C 2 F 4 +20O 2 ], for the reactions of Example 1. This plot shows that reaction products Fe+FEO are gaseous at concentrations in excess of n=4 moles.
EXAMPLE 2
[0047] Combustion in an “Titanium-Chlorinated/Fluorinated Polymer-Oxygen” System
[0048] The combustion system consists of a titanium tube, a chlorinated/fluorinated polymer sleeve, and an excess of oxygen. The adiabatic temperature, evaluated from thermodynamic calculations, indicates that the combustion temperature in systems with chlorine or fluorine is usually lower than in systems with oxygen alone. For example, for a system consisting of 5 moles of titanium and 25 moles of oxygen the combustion temperature is 3,100° K; for a system with 5 moles of titanium, 20 moles of oxygen and 5 moles of —C 2 F 2 — the temperature is 2,500° K and for system of 5 moles of titanium, 20 moles of oxygen and 5 moles of —C 2 Cl 2 — the temperature is 2,900° K.
[0049] More details are presented in FIGS. 4 and 5. FIG. 4 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nTi+(10−n)C 2 Cl 14 +20O 2 ] for the reactions of Example 2. FIG. 4 shows that reaction products Ti+TiCl+TiCl 2 +TiCl 3 +TiCl 4 +TiO+TiOCl+TiOCl 2 +TiO 2 are gaseous. FIG. 5 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nTi+(10−n)C2F4+20O 2 ], for the reactions of Example 2. FIG. 5 shows that reaction products Ti+TiO+TiOF+TiO 2 are gaseous.
EXAMPLE 3
[0050] Combustion in an “Aluminum-Chlorinated/Fluorinated Polymer-Oxygen” System
[0051] The combustion system consists of an aluminum tube, a chlorinated/fluorinated polymer sleeve, and excess of oxygen. The adiabatic temperature, evaluated from thermodynamic calculations, indicates that the combustion temperature in systems with chlorine or fluorine is close to that in systems with oxygen alone. The combustion temperature in these systems can be well above 3,000° K.
[0052] Additional details are shown in FIGS. 6 and 7. FIG. 6 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and sleeve combinations of [nAl+(10−n)C 2 Cl 4 +20O 2 ], for the reactions of Example 3. This plot shows that Al+AlCl+AlCl 2 +AlCl 3 +AlO+AlOCl+AlOCl 2 +AlO 2 +Al 2 O+Al 2 O 2 +Al 2 O 3 are gaseous. FIG. 7 is a plot of equilibrium concentration (left ordinate) and adiabatic temperature (right ordinate) vs. concentrations (n) (abscissa) of lance-and-sleeve combinations of [nAl+(10−n)C 2 F 4 +20O 2 ], for the reactions of Example 3. This plot shows that Al+AlF+AlF 2 +AlF 3 +AlO+AlOF+AlOF 2 +AlO 2 +Al 2 O+Al 2 O 2 +Al 2 O 3 are gaseous.
EXAMPLE 4
[0053] External Carbon Tube as a Focusing Element
[0054] A standard lance “iron-oxygen” is represented by an iron pipe with an array of iron wires inside. Oxygen gas is blown through this arrangement. This assembly has been inserted in a carbon tube. Carbon reacts with oxygen and liberates large amount of heat. Adiabatic temperature of carbon combustion in pure oxygen is above 4000° C. Carbon is also focusing the flame and less heat is dissipated to the environment.
[0055] An iron plate (thickness=1.3″, length=6.0″) was cut by a regular commercial lance in 76 seconds; the cutting rate was 0.20 cm/sec. The same plate was cut by a modified lance with external carbon shield in 43 seconds. The cutting rate increased to 0.38 cm/sec. As an external carbon shield a layer of graphoil material was used.
EXAMPLE 5
[0056] Carbofluorination Piercing of Concrete Slabs
[0057] This example illustrates that using fluorine containing materials improves the efficiency, cutting speed, consumption of oxygen and consumption of the cutting lance essentially.
[0058] Experimental data for the cutting experiment are reported in Table 1, and in FIGS. 8-10. FIG. 8 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1 SiO 2 )+50O 2 +14.56Fe], for the reactions of Example 5. This plot shows that Ca+CaO+Fe+FeO+SiO+SiO 2 are gaseous. FIG. 9 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1SiO 2 )+20.01C 2 F 4 +46.3O 2 +14.56Fe], for the reactions shown in Example 5. This plot shows that CaF+CaF 2 +Fe+FeO+SiF 2 +SiF 3 +SiF 4 +SiO are gaseous. FIG. 10 is a plot of equilibrium concentration (ordinate) vs. temperature (abscissa) for [concrete(3.46CaO+11.1SiO 2 )+20.01C 2 Cl 4 +47.3O 2 +14.56Fe], for the reactions of Example 5. This plot shows that CaCl 2 +FeCl 2 +FeCl 3 +Fe 2 Cl 6 +SiO+SiO 2 are gaseous.
EXAMPLE 6
[0059] Carbofluorination Piercing of Concrete Slabs
[0060] This example provides additional experimental observations on superiority of using fluorinated materials against concrete materials.
[0061] Experimental data for the cutting experiment are reported in the Table 2. Concrete block (thickness=15.0 cm). Note: Hole piercing was completed when penetration was achieved. Number of lances burned is indicated in second column.
EXAMPLE 7
[0062] Carbofluorination Piercing of Concrete Slabs
[0063] This example compares modified lances against concrete walls of different thickness.
Length Burned Type of Lance Time(s) (inches) 1st Concrete Block (thickness = 6.0 cm) BROCO 51.81 24.0 64.18 28.0 BROCO with Fe tubing 32.81 14.0 35.44 15.0 FEP 45.46 19.5 FEP with Fe tubing 25.13 8.5 PTFE 30.63 14.0 PTFE with Fe tubing 26.79 10.0 TFE extruded No penetration — PFA 15.10 9.0 KYNAR 48.71 18.5 2nd Concrete Block (thickness = 7.5 cm) KYNAR No penetration 25.0 PFA 37.87 15.0 PTFE 50.35 20.0 PTFE with Fe tubing 31.02 12.5 FEP 37.84 16.0 FEP with Fe tubing 30.01 11.0 BROCO No penetration 27.5 BROCO with Fe tubing 43.45 19.5 3rd Concrete Block (thickeness = 9.8 cm) BROCO No penetration 28.5 No penetration 28.5 BROCO with Fe tubing No penetration 27.0 PTFE No penetration 26.0 No penetration 29.5 FEP with Fe tubing 46.85 18.0 PEP 67.70 26.0 60.99 25.0 FEP with Fe tubing 38.36 15.0 PFA 43.66 18.0 42.57 16.5
[0064] When BROCO is modified with FEP tubing, the pierce rate was increased by more than 90% (i.e., from 0.073 to 0.139 cm/sec). When BROCO was modified with FEP tubing, the lance burning rate decreased by more than 10% (i.e., from 1.373 to 1.207 cm/sec). When BROCO was modified with FEP tubing, the oxygen consumption needed for piercing a 15 cm deep hole decreased by more than 45% (i.e., from 275.28 to 144.67 liters).
EXAMPLE 8
[0065] Carbofluorination Piercing of Granite Slabs
[0066] Piercing of 0.75 inch thick granite slab by the FEP lance took only 7 sec. of cutting time. Obviously, since granite components are basically silica and alumina both were converted to gaseous products in the course of penetration. Granite objects are ideal targets for a very fast piercing by a modified lance
EXAMPLE 9
[0067] Graphoil Wrap/Aluminum Wires
[0068] Improved cutting/piercing of cutting of iron slabs by using graphoil wrap as focusing element and using aluminum wires to increase the penetration efficiency
[0069] Graphoil layer on the surface of the lance is capable of sharp focusing of the exit hot flame and substantially contributes toward a better performance of the lance. In addition a combination of aluminum and iron wires along with graphoil wrap provides additional improvement of the cutting efficiency.
[0070] The following lances were used in this experiment: (1) BROCO lance (⅜″, linear density=3.933 g/cm); (2) BROCO lance (⅜″) covered by graphoil (thickness=0.015″, width=1.5″, linear density=0.156 g/cm); (3) aluminum lance (⅜″) made from Al tubing (OD=⅜″; wall thickness=0.035″, 6061, linear density=0.648 g/cm) and 7 BROCO Fe wires covered by graphoil (thickness−0.010″) fixed with epoxy glue.
[0071] Experimental data for the cutting experiment are reported in Table 3.
EXAMPLE 10
[0072] Carbochlorination Piercing of Concrete Slabs
[0073] Experimental conditions: oxygen outlet pressure=80 psi; flow=80 liters per minute, experiments with concrete block (thickness=15 cm).
[0074] The experiment used three types of lances: (1) BROCO lance (⅜″) covered by a fluorinated ethylene propylene (FEP) resin−ID=⅜″, wall thickness={fraction (1/16)}″, linear density=1.2249 g/cm) and 10″ long Fe tubing (OD=0.625″, linear density=3.37 g/cm); (2) BROCO lance (⅜″) covered by a chlorinated Teflon® resin-ID=⅜″, wall thickness={fraction (1/16)}″, linear density=1.2234 g/cm, Laird Plastics, Inc.) and 10″ long Fe tubing (OD=0.625″, linear density=3.37 g/cm); and (3) BROCO lance (⅜″) covered by foil of chlorinated Teflon® resin−linear density=1.3205 and 1.2885 g/cm, Honeywell.
[0075] Experimental data for the cutting experiment are reported in Table 4.
[0076] Therefore, while presently-preferred forms ofthe inventive high-speed chemical drill have been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit ofthe invention, as defined ad differentiated by the following claims.
TABLE 1 Time Length O 2 Needed Needed to of for the Lance Molar Make a 15 Lance Run (@ Pierce Burning Material Burned ratio Type of cm Hole Burned 80 l/min) Rate Rate Fe C 2 F 4 Lance: O 2 Lance (sec) (cm) (liters) (cm/sec) (cm/sec) g mol g mol Mol/mol BROCO 187.38 246.38 249.8 0.080 1.315 969 17.4 — — 1.55 183.60 241.30 244.8 0.082 1.314 949 17.0 — — 1.56 (avg) 185.49 243.84 247.3 0.081 1.315 959 17.2 — — 1.56 BROCO 120.51 129.54 160.7 0.124 1.075 509 9.1 78 0.8 1.38 with FEP 110.20 147.32 146.9 0.136 1.337 579 10.4 89 0.9 1.72 109.79 121.92 145.1 0.138 1.121 480 8.6 74 0.7 1.44 114.67 132.08 152.9 0.131 1.152 519 9.3 80 0.8 1.48 (avg) 113.54 132.72 151.4 0.132 1.169 522 9.3 80 0.8 1.49 BROCO 149.93 187.96 199.9 0.100 1.254 1316 23.6 — — 2.64 with Fe tubing BROCO 76.81 71.12 102.4 0.195 0.926 498 8.9 43 0.4 2.03 with FEP and Fe tubing 81.20 83.82 108.3 0.185 1.032 587 10.5 51 0.5 2.28 73.10 81.28 97.5 0.205 1.112 569 10.2 49 0.5 2.46 (avg) 77.04 78.74 102.7 0.195 1.022 551 9.9 47 0.4 2.25
[0077] [0077] TABLE 2 Time Length O 2 Needed Needed to of for the Lance Molar Make a 15 Lance Run (@ Pierce Burning Material Burned ratio Type of cm Hole Burned 80 l/min) Rate Rate Fe C 2 F 4 Lance: O 2 Lance (sec) (cm) (liters) (cm/sec) (cm/sec) g mol g mol Mol/mol BROCO 214.65 292.10 286.20 0.070 1.361 1149 20.6 — — 1.61 183.60 279.40 244.80 0.082 1.522 1099 19.7 — — 1.80 221.13 273.05 294.84 0.068 1.235 1074 19.2 — — 1.46 (avg) 206.46 281.52 275.28 0.073 1.373 1107 19.8 — — 1.62 BROCO 111.11 129.54 148.10 0.135 1.166 509 9.1 78 0.8 1.50 with FEP tubing 118.13 149.86 157.50 0.127 1.269 589 10.6 90 0.9 1.64 96.30 114.30 128.40 0.156 1.187 450 8.0 69 0.7 1.52 (avg) 108.51 131.23 144.67 0.139 1.207 516 9.2 79 0.8 1.55 BROCO 121.15 134.62 161.53 0.124 1.111 529 9.5 169 1.7 1.55 with two FEP tubings 119.06 144.78 158.75 0.126 1.216 569 10.2 182 1.8 1.69 88.60 93.98 118.13 0.169 1.061 370 6.6 118 1.2 1.48 (avg) 109.60 124.46 146.14 0.140 1.129 489 8.8 156 1.6 1.59 BROCO 104.24 100.33 138.99 0.144 0.962 395 7.1 92 0.9 1.29 with KYNAR tubing 91.84 88.90 122.45 0.163 0.968 350 6.3 81 0.8 1.30 96.28 105.41 128.37 0.156 1.095 415 7.4 96 1.0 1.47 84.76 76.20 113.01 0.177 0.899 300 5.4 70 0.7 1.21 85.12 100.33 113.49 0.176 1.179 395 7.1 92 0.9 1.58 (avg) 92.45 94.23 123.26 0.163 1.021 371 6.6 86 0.9 1.36 BROCO 172.72 158.75 230.29 0.087 0.919 624 11.2 182 1.8 1.26 with PTFE tubing
[0078] [0078] TABLE 3 Length O 2 Needed of for the Lance Molar Length Lance Run (@ Cutting Burning Material Burned ratio Type of of Burned 235 l/min) Rate Rate Fe C 2 F 4 Lance: O 2 Lance Cut (cm) (cm) (liters) (cm/sec) (cm/sec) g mol g mol Mol/mol Outlet Pressure = 50 psi; Oxygen Flow = 235 l/min; Steel Plate; Thickness = 2.5 cm BROCO 24.0 35.0 87.3 0.609 0.889 138 2.46 0.358 BROCO + 24.0 25.5 135.2 0.695 0.739 100 1.80 — — 0.298 graphoil BROCO 23.0 32.5 136.9 0.658 0.930 128 2.29 — — 0.375 BROCO 24.5 35.5 152.4 0.630 0.912 140 2.50 — — 0.368 BROCO + 23.0 28.0 139.6 0.645 0.786 110 1.97 — — 0.316 graphoil Outlet Pressure = 50 psi; Oxygen Flow = 235 l/min; Steel Plate; Thickness = 7.0 cm BROCO 7.0 56 289.3 0.095 0.758 220 3.94 — — 0.305 BROCO + 9.5 40.5 222.9 0.169 0.721 159 2.85 — — 0.287 graphoil BROCO 8.5 65 309.1 0.108 0.824 256 4.58 — — 0.332 BROCO + 10.0 37.5 235.4 0.166 0.624 147 2.64 — — 0.251 graphoil Outlet Pressure = 80 psi; Oxygen Flow = 80 l/min; Steel Plate; Thickness = 1.1 cm BROCO 26.0 34.5 49.8 0.696 0.924 136 2.43 — — 1.093 BROCO + 26.0 13.5 40.7 0.851 1.097 53 0.95 — — 0.523 graphoil Al + 7 Fe 25.0 28.5 45.2 0.738 0.841 86 1.54 — — 0.764 wire + graphoil (A) BROCO 26.0 30.0 44.4 0.779 0.899 118 2.11 — — 1.066 BROCO + 25.5 26.5 37.4 0.909 0.945 104 1.87 — — 1.117 graphoil (A) Al + 7 Fe 25.5 37.0 44.7 0.760 1.103 — — 1.003 wire + graphoil BROCO 26.0 30.0 39.9 0.868 1.002 118 2.11 — — 1.186 Al + 7 Fe 26.0 22.5 35.76 0.969 0.839 68 1.22 — — 0.684 wire + graphoil (B) Al + 7 Fe 26.0 26.0 34.7 1.124 1.124 79 1.41 — — 0.908 wire + graphoil (B) Outlet Pressure = 80 psi; Oxygen Flow = 80 l/min; Steel Plate; Thickness = 5.7 cm Al + 7 Fe 7.5 34.0 51.6 0.194 0.878 103 1.84 — — 0.799 wire + graphoil (B) BROCO 5.5 46.0 76.6 0.096 0.801 181 3.24 — — 0.947
[0079] [0079] TABLE 4 Time Length O 2 Needed Needed to of for the Lance Molar Make a 15 Lance Run (@ Pierce Burning Material Burned ratio Type of cm Hole Burned 80 l/min) Rate Rate Fe C 2 F 4 Lance: O 2 Lance (sec) (cm) (liters) (cm/sec) (cm/sec) g mol g mol Mol/mol BROCO 194.88 258.5 259.84 0.077 1.326 1017 18.2 — — 1.57 BROCO + 88.4 84.0 117.87 0.170 0.950 381 6.8 102 1.0 1.48 PCTFE + FE (10″) BROCO + 105.31 104.0 140.41 0.142 0.988 459 8.3 127 1.3 1.53 PCTFE (foil) BROCO + 99.93 95.0 133.24 0.150 0.951 424 7.5 116 1.2 1.46 PCTFE + Fe (10″) | A high-speed chemical drill ( 20 ) for removing portions of a target material ( 30 ), comprises: an elongated tube ( 21 ) formed of a fuel material; a source ( 24 ) of oxidizer; a conduit ( 26 ) for establishing a controllable flow of oxidizer from said source through said tube; and a sleeve ( 28 ) formed of a material containing chlorine and/or fluorine mounted on said tube; whereby, when said drill is ignited and used to remove portions of a target material, the chlorine and/or fluorine in said sleeve material will react chemically with the target material to form gaseous reaction products. | 4 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a continuation of U.S. application Ser. No. 11/646,390, filed Dec. 28, 2006. This application relates to and claims priority from Japanese Patent Application No. 2006-005315, filed on Jan. 12, 2006. The entirety of the contents and subject matter of all of the above is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a technology for communicating data among a plural number of information processing apparatuses through a communication network.
[0003] Through a home network located within a house being built up with using communication means therein, such as, a wired LAN or a wireless LAN or the like, it is possible to view digital contents of pictures, which are stored in a STB (Set Top Box) and/or a device, such as, on other STB or other PC. Also, other than the method of passing through such a network, through a bridge medium, such as, a SD (Secure Digital) card or the like, it is possible to view the digital contents on a PDA (Personal Digital Assistants) and a portable telephone (a mobile phone).
[0004] Various decoders are provided, being different in the kind thereof, depending on the resolution of a screen, the processing power, and/or the size of a memory, etc., which are provided in the device; i.e., many kinds of methods for compression and coding is installed into a PC having high resolution and high processing power, while into the mobile phone having a display screen of QVGA (Quarter Video Graphics Array) is installed a compression/coding method of high compression, for reducing the data size of digital contents, such as MPEG-4 (Moving Picture Expert Group-4), etc., to be small.
[0005] In this manner, since the reproducible moving pictures differs in the format thereof, depending on the kinds of terminals, there is necessity of converting the contents thereof for achieving common use of the contents between the terminals. Such the conversion on the formant of moving pictures is called by “trans-coding”.
[0006] Generally, the trans-coding is executed within one (1) set of a processing apparatus, in many cases, which installs software or hardware having capacity of the trans-coding. However, since the contents themselves are large in the data size, and further large in the throughput thereof, it takes a very long time until when the process is completed, in particular, for the processing apparatus installing therein no hardware for the exclusive use thereof, but depending on the processing speed of a CPU and/or the size of a memory.
[0007] Then, studies were made upon a technology of executing the trans-coding within a short time-period, through executing the trans-coding in parallel upon the contents divided by a certain unit for processing, with using a plural number of processing apparatuses therein. In this, the contents of MPEG are divided into a unit of data block, being called by “sequence”, and the data blocks are transferred to the plural number of processing apparatuses, thereby executing the trans-coding thereon in parallel (for example, Patent Document 1).
[0008] Also, there is already know a technology of installing a distribution function and a trans-coding function in each of the apparatuses on the network, for the purpose of conducting the trans-coding on a plural number of streams, thereby distributing the data streams to the most suitable processing apparatus, by taking into the consideration thereof the processing performance and the format to be converted (for example, Patent Document 2).
[0009] [Patent Document 1] Japanese Patent Laying-Open No. 2004-159079 (page 7 and FIG. 4); and
[0010] [Patent Document 2] Japanese Patent Laying-Open No. 2002-374317 (page 9 and FIG. 14).
SUMMARY OF THE INVENTION
[0011] However, in the home network environment, for a HDD, a TV, etc., corresponding to the processing apparatus, the main processing thereof are the followings; i.e., being used for a user to view a program recorded on each of the processing apparatuses, or to view or record a program broadcasted on the TV. But, use of the processing apparatus in the remote with using the network should be made within such a region that no ill influence is given onto the user who is directly operating the processing apparatus. In particular, when processing a high load, such as, the trans-coding, there is necessity of conducting a control on the load to be processed, so that it does not make full use of the CPU and/or the memory, while making confirmation on time when no user uses the processing apparatus or a situation of processing thereof.
[0012] For that purpose, there is necessity of providing processing performances of the processing apparatus for executing the processes and the present processing load, in case when executing parallel processing with using the network, and a device for enabling to join into distributed trans-coding processes, instantaneously, when completing the process executed at present. Also, in many cases, the home network has a relatively small-scaled construction of equipments, however if trying to apply therein, such a system of transmitting the stream to a processing apparatus, enabling the trans-coding therein, with using distributing function, so as to execute the trans-coding on one (1) content by means of one (1) set of the processing apparatus, although it is suitable for conducting the trans-coding upon the plural number of streams, simultaneously, within a large system, but it results in a system unfitted to the home network system for processing one (1) content at high speed.
[0013] Then, as an aspect of the present invention, it is an object to provide a system, a management server, and/or a processing apparatus for distributing processes, depending on capacity and processing load, among the equipments connected to the home network.
[0014] According to the present invention, it is possible to provide a plural number of trans-coding services to the user, at high speed and with using a plural number of processing apparatuses, within the home network environment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Those and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings wherein:
[0016] FIG. 1 is a view for showing an example of the configuration of a distributed trans-coding system;
[0017] FIG. 2 is a view for showing an example of the hardware constructions of the processing apparatus;
[0018] FIG. 3 is a view for showing an example of the hardware constructions of a home server;
[0019] FIG. 4 is a view for showing an example of the structures of MPEG to be used therein;
[0020] FIG. 5 is a view for showing an example of the constructions of a process management table to be managed within the home server;
[0021] FIG. 6 is a view for showing an example of the structures of a format conversion table to be used within the home server and the processing apparatus;
[0022] FIG. 7 is a view for showing an example of flow of initializing processes; and
[0023] FIG. 8 is a view for showing an example of flow of operations.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] Hereinafter, embodiments according to the present invention will be fully explained by referring to the attached drawings.
[0025] FIG. 1 is a view for showing an example of the system configuration of a trans-coding system 1 , according to an embodiment of the present invention. In this FIG. 1 , a reference numeral 20 depicts a home network of connecting processing apparatuses within a home through a network, and 10 the processing apparatuses, and 30 a home server. Subscriptions are attached to the processing apparatuses 10 , like, 10 a , 10 b , 10 c and 10 d , and do not mean that all of them have the same function and/or the same performance, but only for the purpose of convenience. Regarding the processing apparatuses 10 , in general, they are information equipments, having the trans-coding function therein and being located within a home. The home server 30 accumulating or storing therein contents, as being a target of the trans-coding, has a function for separating MPEG into a unit GOP (Group of picture), so as to distribute them among the processing apparatuses 10 . It is sufficient that the contents, as being the target of the trans-coding, is accumulated or stored into the home server 30 , temporarily, or the contents stored in a Media Server (not shown in the figure) within the home network 1 may be downloaded, to be used in the place thereof.
[0026] The processing apparatuses 10 are information equipments, including a PC (a Personal Computer), a HDD (a Hard Disk Drive) recorder, and/or a TV, etc., each of which can make bi-directional communication through the network. Thus, each mounts a client therein, for enabling a processing request to the equipment connected with the network, such as, RPC (Remote Procedure Call), to the processing apparatus, which is implemented with, for example, UPnP (Universal Plug and Play) and/or Jini, and with respect to a plural number of processing apparatuses having the same functions, it is possible to make control only with an aid of the client mentioned above. At the same time, it is also possible to mount a server for receiving the processing request of the client mentioned above. And, further as a function for transferring the contents, it implements protocols therein, such as, HTTP (HyperText Transfer Protocol), RTP (Real-time Transfer Protocol), RTSP (Real Time Streaming Protocol), etc., thereby having a function of transferring the contents to other processing apparatuses 10 or the home server 30 .
[0027] The home network 20 connects the processing apparatuses, such as, PC, AV equipment, and/or home appliances within home, which are connected to a router (not shown in the figure), with using a wireless LAN (Local Area Network), a wired LAN (Local Area Network), bluetooth, UWB (Ultra Wide Band) therein, so that each of the information equipments can communicate data with each other. The each processing apparatus has an IP (Internet Protocol) address, and enables to use the UPnP (Universal Plug and Play) on the network. Also, it is possible to transfer the contents or a part thereof, with using a protocol, such as, HTTP, RTP, RTSP, etc.
[0028] The home server 30 is information equipment, including PC (a Personal Computer), HDD (a Hard Disk Drive) recorder or a TV, etc., which can make bi-directional communication through the network. Thus, it mounts a client therein, for enabling a processing request to the equipment connected with the network, such as, RPC (Remote Procedure Call), to the processing apparatus, which is implemented with, for example, UPnP (Universal Plug and Play) and/or Jini, and with respect to a plural number of processing apparatuses having the same functions, it is possible to make control only with an aid of the client mentioned above. At the same time, it is also possible to mount a server for receiving the processing request of the client mentioned above. And, further as a function for transferring the contents, it implements protocols therein, such as, HTTP (HyperText Transfer Protocol), RTP (Real-time Transfer Protocol), RTSP (Real Time Streaming Protocol), etc., thereby having a function of transferring the contents to the processing apparatus 10 or a program, which is mounted within the same housing thereof.
[0029] The trans-coding system, which will be explained as the present embodiment, divides the contents stored within the home server 30 into a unit of GOP, with using the equipments mentioned above, and executes the processing request of the trans-coding to the processing apparatuses 10 with using the UPnP, wherein the number of GOP to be transferred to the processing apparatus 10 is increased or decreased, fitting to the performance and/or the condition of processing load of the processing apparatus 10 , and further it enables to execute a plural number of trans-coding processes through managing process identifiers.
[0030] FIG. 2 is a hardware construction view of the processing apparatus, into which the present embodiment can be applied. As is shown in this FIG. 2 , the processing apparatus 10 comprises a CPU (Central Processing Unit) 11 , a main memory 12 , a communication control processing portion 13 , a data storage portion 14 , a trans-code processing portion 15 and a program storage portion 16 . And, each of the constituent elements of the processing apparatus 10 is connected with one another through a bus 17 , so that necessary information can be transmitted among the constituent elements in that structure.
[0031] The CPU 11 executes a predetermined operation in accordance with the program(s), which is/are stored within the main memory 12 and/or the program storage portion 16 in advance.
[0032] The main memory 12 is means for functioning to a work area or for storing a necessary program(s) therein, and can be achieved by, for example, a RAM (Random Access Memory) for the former, and a ROM (Read Only Memory) for the latter, etc.
[0033] The communication control processing portion 13 is the structures for transmitting data with the apparatuses, which are connected with the home network 20 , through the same, and can be achieved by, for example, a modem, a network adaptor, a wireless transmitting apparatus, etc.
[0034] The data storage portion 14 is the structures for storing the contents therein, and can be achieved by, for example, a HDD, an optical disk, a Flash memory, etc.
[0035] The trans-code processing portion 15 has a function of trans-coding the contents, and it is implemented with software or hardware. It can convert a part of the contents transmitted from the home server 30 into a format, which is indicated from the home server 30 . In case when it is implemented with the software, the process may be executed with using the CPU 11 , while extending the program locating within the trans-code processing portion 15 onto the main memory 12 , or separating from the CPU 11 , a CPU and/or a memory may be installed for use of that trans-coding, or only a CPU may be installed with using the main memory 12 provided on a side the host. Or, in case of being implemented with the hardware therein, the process may be executed with using the main memory 12 .
[0036] The program storage portion 16 is means for reserving the program(s) for controlling the operation of the processing apparatus 10 , and it can be achieved by, such as, a HDD, an Optical disk, a Flash memory, etc. Middle software, such as, UPnP and Jini, etc., and/or binary data of an application are stored therein, and that middle ware and/or the application are/is extended on the main memory 12 , so as to be operated on the CPU 11 .
[0037] FIG. 3 is the hardware structure view of the home server 30 , into which the present embodiment can be applied. As is shown in this FIG. 3 , the home server 30 comprises a CPU (Central Processing Unit) 31 , a main memory 32 , a communication control processing portion 33 , a data storage portion 34 and a program storage portion 35 . And, each of the constituent elements of the home server 30 is connected with one another through a bus 36 , so that necessary information can be transmitted among the constituent elements in that structure.
[0038] The CPU 31 executes a predetermined operation(s) in accordance with a program(s), which is/are stored within the main memory 32 and/or the program storage portion 35 in advance.
[0039] The main memory 32 is means for functioning to a work area or for storing a necessary program(s) therein, and can be achieved by, for example, a RAM (Random Access Memory) for the former, and a ROM (Read Only Memory) for the latter, etc.
[0040] The communication control processing portion 33 is the structures for transmitting data with the apparatuses, which are connected with the home network 20 , through the same, and can be achieved by, for example, a modem, a network adaptor, a wireless transmitting apparatus, etc.
[0041] The data storage portion 34 is the structures for storing the contents therein, and can be achieved by, for example, a HDD, an optical disk, a Flash memory, etc.
[0042] The program storage portion 35 is means for reserving the program(s) for controlling the operation of the home server 30 , and it can be achieved by, such as, a HDD, an Optical disk, a Flash memory, etc. Middle software, such as, UPnP and Jini, etc., and/or binary data of an application are stored therein, and that middle ware and/or the application are/is extended on the main memory 32 , so as to be operated on the CPU 31 .
[0043] The process controlling portion 37 controls the processing apparatuses locating on the network, integrally. It is implemented with software or hardware therein.
[0044] Also, within the same housing of the home server 30 may be implemented the function of the processing apparatus at the same time, and in that case, the same function to that of the trans-code processing portion 15 is implemented therein. It is assumed that the home server 30 , as far as it is implemented within the same housing, can be treated to be equal to other processing apparatus 10 , which is connected through the network.
[0045] FIG. 4 is an example of the constructions of MPEG data, as being a format of moving picture. MPEG contents is constructed with one (1) or more of GOP (Group Of Pictures), and further each GOP is constructed with a plural number of frames. GOP is kept to be independent from other GOP within the contents, and it is possible to reproduce the picture for each frame, which a single GOP manages. The contents are made up with one (1) or more of continuous GOPs. Although differing from depending on the frame structures within GOP, one (1) of those GOPs is made of a picture of about 0.5 second, and with the distributed trans-coding according to the present embodiment, the home server 30 distributes processing capacities of the plural number of GOPs to the processing apparatuses, by a unit of GOP, while taking the processing capacity thereof into the consideration. By adopting GOP short in data length to be a unit, it is easy to increase or decrease a GOP number, and it also enables quick distribution of processes, when other processing apparatus 10 newly joins into the processing.
[0046] FIG. 5 is an example of structures of a process management table 100 . The process management table 100 is extended on the main memory 12 of the home server 30 , and it is a table for managing the distributed trans-coding processes. The process management table 100 comprises a sequence ID 105 , a GOP starting position 110 , a GOP number 115 , a processing time 120 , a condition 125 , and a file ID 130 . The sequence ID 105 is a sequence numeral attached to a block of a plural number of GOPs, which are distributed to the processing apparatus 10 . According to the present embodiment, when the home server 30 distributes the GOPs to the apparatuses 10 , it change the number of GOPs to be transmitted, fitting to the processing capacity of the processing apparatus 10 , but as a group of GOPs to be transmitted, selection is made on continuous GOPs with respect to the contents. For that reason, combining the groups of GOPs, while aligning them in an order of the sequence numerals thereof, enables to produce the contents same to that of the contents of a source.
[0047] This sequence ID 105 is also attached to the file ID 130 , which will be mentioned later, and it comes to be a name of the group of GOPs after the trans-coding, to be used when combining the groups of GOPs after the trans-coding. The GOP head position 110 describes therein a head position address of GOP to be transmitted to the processing apparatus 10 . The GOP number 115 is a number of GOPs from the GOP head position 110 , which are transmitted to the processing apparatus 10 . The processing time 120 is a time-period from when executing the processing request to the processing apparatus 10 until when the processing apparatus 10 receiving that processing request sends a notice of completion of the trans-coding process.
[0048] The condition 125 is an area where registrations are made on whether the GOP group corresponding to the sequence ID 105 is already distributed or not, to the processing apparatus 10 locating on the home network 20 , on whether the process is already completed or not on the processing thereof, on whether the distribution process is conducted or not yet, on whether it is already timeout or not, and/or on whether re-distributing process is conducted or not. The file ID 130 is an ID, to be transmitted as the file name, at the same time when the GOP group after the trans-coding is transmitted to the home server 30 . The home server 30 accumulates or stores the GOP group after processing and also the file ID 130 received at the same time, to be the file name of the GOP group mentioned above, into the data storage portion 34 within the home server 30 .
[0049] FIG. 6 shows an example of the structures of a format conversion table 200 . The format conversion table 200 is a table to be transmitted from the home server 30 to the processing apparatus 10 , when conducting an initializing process, and it describes therein format information of the contents on a target, on which the trans-coding should be done, and format information after the trans-coding. As the constituent elements thereof are an process ID for discriminating the trans-coding process, a pre-conversion format 210 , and a post-conversion format 215 . This table is treated as a table, from a viewpoint of convenience, however when it is transmitted, it may be changed into a format, such as, XML (extensible Markup Language) or CSV (Comma Separated Values) to be easily treated with UPnP or the like, or a combination of them.
[0050] Next, an initializing process according to the present embodiment will be explained, by referring to the drawings.
[0051] FIG. 7 shows a method of the initializing process before executing the distributed trans-coding. First of all, in a step S 300 , from the viewing apparatus, on which a user views the contents, the equipment information of that viewing apparatus (resolution, screen size, corresponding format, etc.) and information o the contents to be viewed (for example, the contents ID and/or URI (Uniform Resource Identifier) for discriminating the contents are transmitted to the home server 30 . As a presumption, the viewing apparatus obtained therein a list of contents, from a contents server, which is located within the home or in an outside thereof, therefore having the contents information therein.
[0052] In a step S 305 , when obtaining the equipment information and the contents information, the home server 30 downloads the contents upon basis of the contents information, so as to store them into the data storage portion 34 . In addition thereto, it obtains detailed information of the contents from the contents server, or it analyze them when downloading the contents, so as to obtain them.
[0053] In a step S 310 , the home server 30 searches the processing apparatus of providing the trans-coding service, being located on the network 20 , with using UPnP, etc. In case where no such desired processing apparatus 10 can be found, as a result of the search, a fact that the trans-coding cannot be done is noticed to the user who is operation the viewing apparatus, through the network and with using the communication control processing portion 33 . In this instance, error information may be notices in the form of a return value when transmitting the equipment information and the contents information, or it may be stored into the data storage portion 34 within the home server 30 , to be noticed on the viewing apparatus as the error information when the viewing apparatus joins into the home network 20 . As a method for noticing, an E-mail may be also applied for.
[0054] In a step 315 , in case where no desired processing apparatus can be found as the result of the step S 310 , the initializing process is finished. If such desired processing apparatus be found as the result of the step S 310 , then the process moves into a step S 320 .
[0055] In the step 320 , obtaining is made on a function list of the trans-coding service, which the found processing apparatus 10 has, and further on a format list, on which the trans-coding can be made. The format list includes, at least, a multiplexing method, Video format, Audio format, and a screen size, and the processing apparatus lists up all of items, which can be combined with, and transmitted them to the home server 30 .
[0056] In a step S 325 , from the format list obtained in the step S 320 , including the formats on which the trans-format can be made within each the processing apparatus 10 , search is made on the combinations, on which the conversion can be made, with using pre-conversion contents format to be the contents information of the contents, which the user wishes while post-conversion contents to be the format of the contents, which can be deal with the equipment information of the viewing apparatus. In a step S 330 , if in case where no corresponding processing apparatus 10 can be found as the result of the search in the step S 325 , the fact that the trans-coding cannot be made to the home server 30 , and the home server 30 gives a notice to the user who is operating the viewing apparatus, with using the communication control processing portion 33 . If such desired processing apparatus be found, then the process moves into a step S 335 .
[0057] In the step S 335 , the home server 30 issues the process ID 205 for managing the trans-coding process, and produces the format conversion table 200 and the process management table 100 and the list of the processing apparatus(es), which can execute the trans-coding, to be stored into the main memory 32 with reference to the process ID 205 . Further, the format conversion table 200 and the process ID 205 are transmitted to the processing apparatus 10 , which can execute the trans-coding process therein. When receiving the format conversion table 200 and the process ID 205 , the processing apparatus 10 memorizes them into the main memory 12 with reference thereto. The format conversion table 200 and the process management table 100 are prepared for each process ID. The format conversion table 200 is produced upon basis of the search result of combination, which is searched in the step S 325 , and the process management table 100 is produced upon basis of the contents information.
[0058] Next, operations of the present embodiment will be explained by referring to figure attached.
[0059] FIG. 8 shows a processing method when executing the distributed trans-code process.
[0060] In a step S 400 , upon receipt of the initialization processing shown in FIG. 7 , the list of the processing apparatuses 10 tied with the process ID 205 issued, the format conversion table 200 and the process management table 100 are obtained. Also, further a processing unit time and an initializing GOP number are set up. The processing unit time is a kind of time-out value, i.e., after the processing request is made from the home server 30 to the processing apparatus 10 , those for the GOP numbers, on which the trans-coding process is finished, are sent to the home server after elapsing that processing unit time, and further a continuation notice is issued through UPnP. After the continuation notice, the processing apparatus 10 executes the processing for GOPs, on which the trans-coding process is not yet finished, and further, after elapsing the processing unit time after the continuation notice, it transmits GOPs to the home server 30 , on which the processing is finished. If the processing of GOP is finished before that processing unit time, GOP finished with processing is transmitted to the home server 30 , before it does not reach to the processing unit time. The reason of providing the processing unit time lies in that an assumption is made that each the processing apparatus 10 be a home appliance, then possibility must be considered, such as, unexpected shutdown of an electric source thereof and/or sudden pull-out of a network cable. For that reason, it is effective to transmit the process (es) to the home server 30 if finishing within at least the processing unit time, as the result thereof. Details of the processing method will be explained after explanation of a step S 405 .
[0061] In a step S 405 , with using UPnP, etc., the home server 30 makes a processing request for trans-coding, to the processing apparatus 10 on the list of the processing apparatuses. Within the processing request, in addition to the process ID 205 and the sequence ID 105 , there are described URI of contents and the processing unit time. In this instance, on the process management table 100 are described the sequence ID 105 , the GOP head position 110 and the GOP number 115 , additionally. By the way, the GOP number to be transmitted firstly to the processing apparatus 10 is an initial GOP number, i.e., “M” pieces.
[0062] In a step S 410 , when receiving the processing request, the processing apparatus 10 makes access to URI of contents, and thereby transmitting the process ID 205 and the sequence ID 105 thereto. The home server 30 , when receiving the request of obtaining contents, the process ID 205 and the sequence ID 105 , transmits the initial GOP number “M”, and thereby renewing the process management table 100 (a step S 415 ). Thus, it turns the condition 125 into “distributed”. In a step S 420 , the processing apparatus 10 obtain the format conversion table 200 locating in the main memory 12 , and execute the trans-coding process onto a group of GOPs obtained from the server 30 .
[0063] In a step S 425 , the processing apparatus confirm the elapse of the processing unit time therein. If it does not reach to the processing unit time, it continues the trans-coding process. If it reaches to the processing unit time, the process moves into a step S 430 .
[0064] In the step S 430 , “N” number of GOPs, which are finished until reaching to the processing unit time, are transmitted to the home server 30 . Into the data storage portion 34 of the home server 30 are stored the process ID and the sequence ID and a number of repeating the processing unit time to be a file name.
[0065] In a step S 435 , subtracting is made on GOP number “N”, which are processed with the processing unit time, from GOP number “M” received, and a result thereof is putted into “M”.
[0066] In the step S 440 , in case where GOP number is equal or greater than “0”, it is determined that there is/are GPO(s) which cannot be processed within the processing unit time, and then the process of the trans-coding is continued. In case where GOP number is equal to “0”, it is determined that all GOPs received are processed, and then the process moves into a step S 445 .
[0067] In the step S 445 , the processing apparatus 10 transmits an end process notice to the home server 30 , adding the process ID 205 and the sequence ID 105 with using UPnP. The home server 30 renews the process management table 100 , and changes the condition 125 into “processed”, and further it changes the data name after processing, which is transmitted from the processing apparatus 10 , into a file ID 130 .
[0068] In a step S 450 , while continuing the trans-coding process, a process continuing notice is transmitted to the home server, being attached with the process ID 205 and the sequence ID 105 .
[0069] In a step S 455 , the home server 30 makes determination from the processing result of the processing apparatus 10 , so as to change GOP number “M” into the GOP number, which can be finished within the processing unit time, and add the next process onto the process management table 100 , thereby moving into the step S 405 .
[0070] From the above, it is possible to change the GOP number to be requested for processing, fitting to the performances and the load condition of the processing apparatus 10 , and with management of the process ID 205 , and with processing them in plural numbers thereof per the process ID 205 , it is possible to construct the distributed trans-coding system suitable to the home network.
[0071] With the present embodiment, another explanation may be made as below.
[0072] The processing apparatuses 10 and the home server 30 have communication portions for transmitting data through a communication network, such as, the wired LAN, wireless LAN, bluetooth, or an electric power line.
[0073] The processing apparatus 10 provides the list of formats, on which the trans-coding can be made, for the format before trans-coding and the format after trans-coding, to the home server 30 managing the processing apparatus 10 , with using the communication portion.
[0074] The home server 30 selects a pair of the formats from the list of format, which is provided by the processing apparatus 10 , and further transmits the contents of the formats before trans-coding in the pair, with using the communication portion.
[0075] The home server 30 distributes the process identifier for each of format conversion processes.
[0076] The processing apparatus 10 executes the format conversion, with using the process identifies, which are distributed by the home server.
[0077] The processing apparatus 10 , receiving a plural number of continuous groups of GOPs, being included within one (1) contents, executes the format conversion upon GOPs within the processing time, which is set up by the home server 30 , and further, it returns a number of GOPs to the home server 30 , being equal to or less than that of the GOP groups obtained, with respect to GOPs, upon which it can execute the format conversion within the processing time set up.
[0078] The processing apparatus 10 conducts the format conversion, continuously, upon the plural number of continuous GOP groups, which are not yet processed within the processing time set up, even after elapsing that processing time set up, and it turns the GOP groups, on which the format conversion can be made within the next set-up processing time, back to the home server.
[0079] The processing apparatus 10 , managing the format conversion information, describing therein the process identifiers, which are designated by the home server, and the formats of contents before conversion and the formats of contents after conversion, searches for the format conversion information with using the process identifiers to be utilized when obtaining the GOP groups from the server, so as to obtain the format conversion information, and thereby converting the GOP groups obtained from the home server into the format, which the home server requires.
[0080] The processing apparatus 10 accumulates or stores the data after format conversion into the home server 30 , with designating the process identifiers and the file names added with the sequence IDs indicative of the order of the GOP groups.
[0081] The home server 30 obtains the list of the formats, on which the trans-coding can be made, from the processing apparatus 10 , with respect to the format before trans-coding and the format after trans-coding, with utilizing the communication portion.
[0082] The home server 30 controls the format conversion processes of the plural number of information processing apparatuses by means of the process identifiers, and thereby executing the plural number of format conversion processes.
[0083] The home server 30 , managing the format conversion information, describing therein the process identifiers, the formats of contents before conversion, and the formats of contents after conversion, transmits the format conversion information to a predetermined processing apparatus(es), with using the communication portion, thereby designation the method for the format conversion.
[0084] The home server 30 presumes the processing capacities or performances of the processing apparatus (es), to which the plural number of continuous GOP groups are transmitted, by knowing a number of GOPs, upon which the format conversion can be made, among the plural number of continuous GOP groups transmitted within the processing time set up.
[0085] The home server 30 adjusts the number of the continuous GOP groups to be transmitted to the processing apparatus (es) 10 , and it also takes the capacities or performances of the processing apparatus(es) 10 into the consideration.
[0086] The home server 30 sets up the processing time, before transmitting the plural number of continuous GOP groups to the processing apparatus(es) 10 .
[0087] The home server 30 combines the GOP groups after the conversion, which are transmitted from the processing apparatus(es) with the process identifiers describing the file names thereon, with using the sequence identifiers, and thereby procuring the contents after conversion.
[0088] According to the embodiment explained in the above, for example, it is possible to execute the plural number of format conversions, while distributing them into the processing apparatuses, and even if the format conversion process is on the way thereof, it is possible to join into the processing, or withdrawal during the processing.
[0089] However, the present invention should not be restricted only to the embodiments mentioned above, and it is of course that it is susceptible with various kinds of constructions, but not departing from the gist of the present invention.
[0090] The present embodiment mentioned above was made upon an assumption that the processing apparatuses described therein are the digital home appliances, such as, HDD recorder, PC, mobile phone, etc., and the home server is the PC, HDD recorder, etc. Also, relating to the processing contents described herein, they may be installed in the form of middle ware of the information apparatuses mentioned in the above.
[0091] The present invention may be embodied in other specific forms without departing from the spirit or essential feature or characteristics thereof. The present embodiment(s) is/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 by the forgoing description and range of equivalency of the claims are therefore to be embraces therein. | For providing a user a plural number of trans-coding services with using a plural number of trans-coding services, at high speed, within a home network environment, an information processing apparatus is provided with a function of providing a list of formats, on which format conversion can be made, to a home server, and a function of managing the format conversion processes with using process identifiers, which are shared in common with the server and the information processing apparatus, each of the process identifiers being tied with information of a format conversion method, wherein the format conversion is executed upon a part of contents divided within the home server, following the process identifier designated by the home server, to grasp performances of the information processing apparatuses by measuring throughput per a unit time in the format conversion, and an adjustment is made on an amount of data to be transferred from the home server to the information processing apparatus in the next time, thereby enabling high speed processing of the format conversions. | 7 |
BACKGROUND OF THE INVENTION
[0001] Defined as the analysis of material properties in industrial manufacturing processes, process analysis has been performed for several decades in a wide variety of industries. These industries include chemical, petrochemical, petroleum, pharmaceutical, food & beverage, pulp & paper, and agricultural. A former common implementation of process analysis consisted of manually extracting samples from a process and carrying the samples to a laboratory for analysis. Over time, process analysis evolved from off-line analysis to a continuous on-line analysis where samples are extracted by automated sampling systems and carried in slip streams to process analyzers.
[0002] The primary advantage of on-line process analysis is the reduction of the time interval between sample extraction and data generation. The faster response time provides greater control of manufacturing processes leading to increased product yield, improved product quality (consistency), reduced in-process inventory, reduced operating and maintenance workforce, reduced energy consumption, reduced consumption of raw material inputs, and reduced production of waste streams.
[0003] Several instruments are currently used for industrial process monitoring. Gas chromatographs (GCs), for example, measure differences in molecular mobility to identify multi-component samples. GCs have high specificity and high sensitivity. They require shielded enclosures for protection from the environment, a supply of column gas, frequent maintenance, and water trapping especially in corrosive applications. These instruments are widely discussed in published literature.
[0004] Infrared (IR) instruments rely on material absorption to analyze samples. IR instruments include Fourier Transform Infrared (FTIR) analyzers, IR dispersive analyzers, and non-dispersive IR (NDIR) analyzers. Non-dispersive instruments include filter and non-filter based instruments. IR instruments have displaced other types of instruments due to higher speed, sensitivity, and specificity. IR instruments typically induce a net change in dipole moment in the molecules of a sample as a result of rotational or vibrational motion. The method works well for many species, but fails for homonuclear species such as nitrogen, oxygen, chlorine, hydrogen, and fluorine that cannot have a net change in dipole moment.
[0005] Electrochemical sensors provide other means for quantifying species concentrations. These types of sensors are typically limited to the measurement of a single species and often supplement IR methods.
[0006] An alternative approach for industrial process monitoring includes the use of Raman methods. Raman spectroscopy is based on the inelastic scattering of light off molecules. As a process analysis technique, Raman spectroscopy has advantages over other techniques as it requires no sample extraction or sample preparation, can perform continuous in-situ quantitative measurements, can analyze pipe content through a sight window, can detect molecules that other techniques cannot, and is unaffected by water molecules.
[0007] As a result, Raman spectrometers have found a niche in the market where no other viable solutions exist. Despite these advantages, broad adoption of Raman spectrometers has been hindered because they are very expensive to buy, install and maintain, require frequent calibrations and skilled operators and, in general, lack the robustness necessary to operate in harsh plant environments.
[0008] In order for a Raman instrument to be widely accepted for industrial process monitoring, it must have low cost and have high performance. The present invention uses fewer and more readily available components than other Raman instruments, and is easily manufactured and adapted to different applications. It eliminates the use of optical fiber hence achieves high optical throughput. The invention also uses increased amplification with robust multi-stage photon-to-electron amplifiers, and optimized optical filter designs. Further, the invention can withstand tough industrial conditions and uses low cost and wavelength stabilized laser sources.
[0009] Raman spectrometers are part of a general class of instruments called optical analyzers. Optical analyzers are generally based on one of six phenomena: absorption, fluorescence, phosphorescence, scattering, emission, and chemoluminescence. These phenomena can occur in the ultraviolet, visible, and infrared portions of the spectrum. A typical instrument contains five basic elements: a radiation source, a sample container, a spectral element to look at a specific region of the spectrum, a detector that converts photons to electrons, and a signal processor. Raman is classified as a second order scattering process in that Raman scattered photons are created from the inelastic interaction of incident light photons with the molecules of the sample. These second order photons are weak, typically 10 6 to 10 7 times less intense than first order elastically-scattered photons.
[0010] U.S. Pat. Nos. 4,648,714, 4,784,486, 5,521,703, and 5,754,289 use Raman scattering to perform gas analysis. Gases flow through a section of tube while a laser beam is directed into it. These inventions require a slip stream or redirection of the sample away from a pipeline or reactor. Most use a filter wheel in conjunction with a single detector. U.S. Pat. No. 5,521,703 differs slightly from the other three in that its multiple detectors are arranged along the length of gas sampling cell within a laser resonator configuration. U.S. Pat. No. 5,754,289 teaches the use of a filter wheel in conjunction with an integrating sphere for the sample. The related U.S. Pat. Nos. 5,386,295, 5,357,343, and 5,526,121 teach the use of a filter wheel spectrometer coupled to reference and sample elements using fiber optic probes. U.S. Pat. Nos. 5,963,319 and 6,244,753 teach the use of a dispersive spectrometer and fiber optic couplers for industrial process monitoring. Fiber optic couplers are known to limit optical throughput.
SUMMARY OF THE INVENTION
[0011] The present invention provides a photometric analyzer incorporated into a small, low cost, and robust package for in-situ industrial process monitoring applications. The analyzer can measure homogeneous or inhomogeneous chemical mixtures made up of one or several solid, liquid, or gaseous analytes. The analyzer uses Raman scattering and maximizes optical throughput, increases the signal-to-noise ratio of the system, and incorporates on-board quantification of process concentrations. The present invention requires neither extraction nor redirection of material from the originating process pipeline or vessel. It can analyze chemical concentrations remotely from a process, i.e. the analyzer can be separated or physically detached from the process pipeline or vessel. The present invention can analyze chemical composition in processes operating under a wide range of conditions. Examples include process pressures from sub-atmospheric to thousands of psi, process temperatures from sub-zero to hundreds of degrees Celsius, and process flows from stagnant to hundreds of liters per minute.
[0012] The analyzer comprises a laser radiation source, which may be any type of laser but preferably a solid state laser diode. The temporal characteristics of the laser radiation are controlled by an integrated laser controller module that, in turn, is controlled by a microprocessor. The laser output is spatially shaped and directed across a free-space light path toward the process sample. Free-space propagation is defined as the propagation of an optical beam predominantly through gases or vacuum with discrete optical components and windows to control focus, spectral characteristics, and other properties. The laser radiation is then incident upon the sample located outside the analyzer. The Raman radiation scattered by the sample is collected by the free-space shaping optics of the analyzer, which adjust the spatial characteristics of the scattered radiation for transport to the detector module. One or more spatial and/or optical filters are used to reduce or eliminate the amount of radiation at the excitation wavelength that is introduced into the detector module without substantially reducing the amount of desired Raman signal. One or more additional filters are used to extract targeted spectral bands from the Raman signal. The signal of each spectral band passes through low-noise, high-gain amplifiers that increase analog signal levels without introducing significant perturbations. The analog signal levels are quantitatively measured by means of analog-to-digital signal converters. The resulting digital signals are processed by a dedicated embedded microprocessor or some other data control system. Using calibration information from known sources such as chemical samples or suitable reference standards, the signals generate a quantitative measurement of the analytes either directly or via a mathematical deconvolution.
[0013] The present invention can be customized for specific applications by identifying which of several chemical species are to be measured. Ideally, the Raman radiation of the desired chemical species comprises spectral components that are largely independent from the scattered radiation of the other molecules.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic representation of the invention;
[0015] FIG. 2 is a schematic representation of a preferred embodiment of the invention;
[0016] FIG. 3 is a schematic representation of another preferred embodiment of the invention; and
[0017] FIG. 4 is a schematic representation of a portion of the optical layout of yet another preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] A schematic representation of the invention is shown in FIG. 1 . The black arrows indicate the direction of the primary optical signals; the gray arrows indicate the direction of the primary electrical signals. A radiation module 110 which includes a laser radiation source is controlled by a control microprocessor 150 . The laser source can be of any type but is preferably a solid state laser diode. In a preferred embodiment of the invention, the laser radiation source emits radiation primarily at a wavelength of 785 nm.
[0019] After leaving the radiation module, the laser radiation is transferred via free-space optics to a free-space optics module 120 . In a preferred embodiment of the invention, the optics module includes a selective reflector which treats the laser radiation differently than other radiation, in particular the radiation that comprises the return signal (defined below). The selective reflector may reflect the laser radiation while allowing other radiation to pass through, or may allow the laser radiation to pass through while reflecting other radiation. The selective reflector relies on one, or a combination of several, mechanisms including: (i) spatial selectivity such as the deposition of a mirror or transparent aperture in one portion of the selective reflector; (ii) wavelength selectivity; or (iii) polarization selectivity. In one preferred embodiment, the selective reflector has a large clear area with a small reflective spot in its center to reflect the collimated laser radiation. In another preferred embodiment, the selective reflector comprises a dichroic filter or is coated with an optical thin film that reflects light at the excitation laser wavelength and transmits light at longer and shorter wavelengths.
[0020] After leaving the optics module 120 , the laser radiation exits the analyzer 100 and is incident upon a sample located outside the analyzer. The sample may be any of a large number of chemical materials and may or may not be contained behind a sample port window that is transparent to both the laser radiation and the return-signal radiation. The sample and sample port window are not part of the analyzer. The analyzer relies on Raman scattering of laser radiation by the sample. The physical processes that govern this scattering generally include both inelastic scattering (wavelength-shifting) processes, such as Raman scattering, and elastic scattering (wavelength-preserving) processes such as Rayleigh and Mie scattering. The desired signal (known as the return signal) includes the inelastically scattered Raman radiation; the undesired signal (known as the noise) includes elastically scattered radiation plus parasitical sources such as stray light. A portion of the return signal and noise is collected by the free-space optics module 120 and makes up the return radiation (known as the backscattered radiation). The spatial and spectral characteristics of the return radiation are adjusted by the free-space optics module. One or more spatial and/or optical filters are used to reduce or eliminate the amount of radiation at the excitation wavelength without substantially reducing the amount of desired return signal. After exiting the optics module, the return radiation is transferred via free-space optics to the photometric detector module 130 .
[0021] The photometric detection module includes one or more filters that extract targeted spectral bands from the return signal corresponding to specific chemicals of interest. The filters can be bandpass or notch filters, and can be fixed-wavelength or tunable filters. After separation from the composite beam, the selected wavelengths of light are directed to photo-sensitive detectors capable of detecting photon streams. The detectors generate analog voltage and/or current responses which are proportional to the number of photons detected at a given time. The composite signal-bearing light-stream is divided into discrete paths such that the photo-detectors receive measurable quantities of light in real time. In a preferred embodiment of the invention, multiple filters and multiple detectors are used to measure multiple wavelength components simultaneously. An advantage of simultaneous detection is the reduction of the total signal collection time to achieve a desired measurement sensitivity. Another advantage of simultaneous detection is the ability to distinguish analyte concentration changes from common mode effects such as sample density changes or variations in sample transparency to incident radiation. In another preferred embodiment of the invention, the filters are positioned on a movable stage such as a rotating wheel, linear slide, or other geometric configuration permitting wavelength separation. In a third preferred embodiment of the invention, wavelengths are separated using an electro-optic filter utilizing either Pockels or Kerr media for the monochromator. An advantage of using a tunable filter, electro-optic filter, or movable stage is the ability to use a lower number of detectors. In a fourth preferred embodiment, wavelengths are separated using a diffractive element (such as a reflective or refractive grating) or a dispersive element. In this embodiment, the different wavelength components can be detected with an array of detectors.
[0022] In some cases, such as the analysis of low-pressure gas, the detector signals are increased using low-noise, high-gain amplifiers capable of increasing analog signal levels without introducing significant perturbations. In a preferred embodiment, the analog signal paths are divided into stages, each designed for stability and low susceptibility to electronic and thermal noise. The inputs to each amplifier are shielded to prevent electronic pickup of signal from external sources. The analog signal levels are quantitatively measured by means of analog-to-digital signal converters.
[0023] Two-way communication between the photometric detection module and control microprocessor 150 is carried on digital control bus 140 . In a preferred embodiment of the invention, each signal is monitored with a dedicated analog-to-digital converter so as to minimize integration time and add speed to the data analysis without signal degradation. The microprocessor provides digital data such as measurement data and analyzer status information to one or more external devices. In a preferred embodiment of the invention, the analyzer also employs in-situ physical presentation of data which can be monitored without an external device.
[0024] A schematic representation of another preferred embodiment of the invention is shown in FIG. 2 . Optical radiation is generated by laser source 212 . The radiation source is temperature controlled by laser cooler 214 , and the radiation is shaped spatially and spectrally by beam shaping optics 213 , which in one preferred embodiment, include lenses to control the spatial extent and collimation of the beam, a wavelength selective reflecting element to control and stabilize the central wavelength of the beam, and optical filters to limit the spectral extent of the beam. The temporal characteristic of the laser radiation is controlled by laser controller 211 which, in turn, is controlled by control microprocessor 250 . In one preferred embodiment, the temporal characteristic of the beam incorporates a boxcar modulation at a frequency below 10 MHz to facilitate discrimination against stray optical background. The laser source 212 , laser cooler 214 , beam shaping optics 213 , and laser controller 211 are included in radiation module 210 .
[0025] Upon leaving the radiation module, the laser radiation enters the free-space optics module 220 . The free-space optics module includes a selective reflector 222 with a large clear area and a small reflective area in its center to reflect the laser radiation. After being reflected by the selective reflector, the laser radiation is incident upon objective lens 221 whose function it is to facilitate delivery of the laser radiation to the sample under test.
[0026] The objective lens 221 collects the backscattered radiation from the sample under test. The backscattered radiation travels to the selective reflector 222 which lets a large portion of the signal through and reflects the light in the center of the reflector. The spatial characteristics of the transmitted signal from the selective reflector are adjusted by the return signal shaping optics 223 . The excitation blocking filter 224 comprises one or more lenses and one or more spatial or optical filters that serve to reduce or eliminate the amount of undesired radiation that enters the detector module 230 at the excitation laser wavelength. The excitation blocking filter 224 does not substantially reduce the amount of desired return signal but reduces the undesired elastic component of the return radiation at the excitation laser wavelength. The remaining portion of the undesired radiation is monitored to serve as a diagnostic signal that contains information regarding the operation of the instrument and the condition of the process being analyzed.
[0027] The signal leaving the excitation blocking filter is incident upon one or more mirrors 225 that serve to redirect the signal towards the photometric detector module 230 and facilitate optical alignment of the analyzer. The detector module includes a filter module 231 . Upon entering the filter module, the return signal is incident at non-normal angles upon a multiplicity of optical bandpass filters 232 , each of which selectively transmits radiation at a fixed and narrow wavelength band and reflects radiation of other wavelengths towards the next filter in the chain, thus creating a devious and divaricate optical path within the filter module. Signal that is transmitted through any of the bandpass filters is focused by a detector lens onto a photodetector element 233 . Examples of photodetector elements include Silicon photodetectors, avalanche photodetectors, or photomultiplier tubes. Although six filters and detector elements are shown in FIG. 2 , the analyzer is operable with any number of filters and detector elements. In an alternate embodiment of the invention, the filters are positioned on a movable stage such as a rotating wheel or a linear slide.
[0028] In a preferred embodiment of the invention, the optical bandpass filters 232 are assembled in removable and replaceable cartridges. These cartridges are designed such that the filters 232 are pressed and held against a reference surface to provide a low-cost, easily-reconfigurable, and easily-manufacturable assembly. In the specific embodiment shown in FIG. 2 , two cartridges can be used each holding half the filters.
[0029] The output currents from the photodetector elements 233 are amplified and converted to signal voltages by photodetector amplifiers 234 . Since the laser source 212 is modulated, the photons scattered by the sample have a distinct identification and are differentiated from undesired photons from other sources. The signals from the photodetector amplifiers 234 are demodulated into DC voltage or electronic current signal levels by lock-in amplifiers 235 . Each demodulator is synchronously tied to the laser excitation modulation to allow for in-phase measurements.
[0030] The analog signal levels are quantitatively measured by means of analog-to-digital signal converters 236 . In a preferred embodiment of the invention, these signal converters perform high-resolution averaging functions. Unwanted noise (including noise generated by the modulation source) is filtered, which provides more accurate DC measurements.
[0031] The photodetector elements 233 are actively temperature stabilized by heating and/or cooling devices 237 coupled with a PID loop temperature controller in order to minimize thermal noise and drift.
[0032] The analyzer is calibrated after assembly using known quantities of reference chemicals or a calibrated fluorescence source. The intensity of the optical signal is directly proportional to the molecular density. This proportionality provides a way to relate observed Raman photon power to sample composition. Alternatively, a quantitative measurement of the chemicals can be generated using a mathematical deconvolution employing information from a combination of photodetector elements. In another embodiment of the invention, the signals from the photodetector elements are used to provide non quantitative information about a process such as changes in concentration as a function of time or operating conditions. With the information provided by the analyzer, a user can adjust or otherwise control process conditions.
[0033] A schematic representation of another preferred embodiment of the invention is shown in FIG. 3 . This embodiment is similar to the one shown in FIG. 2 except for the detector module 330 . The detector module contains a single detector element 333 . The optical filtering element 332 comprises either a single variable filter (such as a tunable filter or an electro-optic filter) or multiple fixed filters on a movable stage (such as a rotating wheel or linear slide). The optical filtering element 332 selectively transmits radiation at a desired wavelength band. The transmitted signal is detected by detector element 333 . Examples of detector elements include Silicon photodetectors, avalanche photodetectors, or photomultiplier tubes. A different wavelength band is allowed through the filtering element 332 by changing the properties of the filtering element or by moving the stage.
[0034] The output current from the detector element 333 is amplified and converted to signal voltages by a detector amplifier 334 . The signal from the detector amplifier 334 is demodulated into DC voltage or electronic current signal level by a lock-in amplifier 335 . The analog signal levels are quantitatively measured using a high-resolution analog-to-digital signal converter 336 .
[0035] In another preferred embodiment of the invention, one or more additional filters and detectors are added to the detector module 330 in order to analyze other desired wavelength bands.
[0036] A schematic representation of a portion of yet another preferred embodiment of the invention is shown in FIG. 4 . Laser radiation from radiation module 410 is incident on free-space optics module 420 . The objective lens 421 is common to both the laser radiation delivery and return signal collection but, unlike in the specific embodiment presented in FIG. 2 , the selective reflector 422 is used only to deliver the laser radiation to the sample. In the specific embodiment shown in FIG. 4 , selective reflector 422 need not be wavelength selective.
[0037] Although the invention has been shown and described with respect to several exemplary embodiments thereof, various changes, omissions and additions to the form and detail thereof, may be made therein, without departing from the spirit and scope of the invention. | An optical apparatus for measurement of industrial chemical processes. The analyzer uses Raman scattering and performs measurement of chemical concentrations in continuous or batch processes. The analyzer operates at a standoff distance from the analyte (or analytes) and can measure concentrations through an optical port, facilitating continuous, non-destructive, and non-invasive analysis without extracting the analyte or analytes from the process. The analyzer can measure one or several solid, liquid, or gaseous analytes, or a mixture thereof. | 6 |
RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No. 10/632,198, filed 31 Jul. 2003, entitled MULTIPLE INTERVENTIONLESS ACTUATED DOWNHOLE VALVE AND METHOD; and Provisional Application Ser. No. 60/399,987, filed 31 Jul. 2002, which are incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates in general to actuation of valves and isolation of sections of a borehole and more specifically to an apparatus and method for actuating a downhole valve more than once without physical intervention.
BACKGROUND
[0003] In drilling operations it is common practice to include one or more valves connected within a pipe string to separate and control the flow of fluid between various sections of the wellbore. These valves are commonly referred to as formation isolation valves (FIV). The formation isolation valve can be constructed in numerous manners including, but not limited to, ball valves, discs, flappers and sleeves. These valves are primarily operated between an open and closed position through physical intervention, i.e. running a tool through the valve to open. To close the valve the tool string and a shifting tool are withdrawn through the formation isolation valve. The shifting tool engages a valve operator that is coupled to the valve moving the valve between the open and closed position.
[0004] It is often desired to open the FIV without physical intervention after the valve has been closed by physical intervention, such as by running a shifting tool through the FIV via a wireline, slickline, coil tubing or other tool string. Therefore, it has been shown to provide an interventionless apparatus and method for opening the FIV a single time remotely from the surface. Interventionless is defined to include apparatus and methods of actuating a downhole valve without the running of physical equipment through and/or to the operational valve. Apparatus and methods of interventionlessly operating a downhole valve a single time are described and claimed by the commonly owned United States Patents to Dinesh Patel. These patents include, U.S. Pat. Nos. 6,550,541; 6,516,886; 6,352,119; 6,041,864; 6,085,845, 6,230,807, 5,950,733; and 5,810,087, each of which is incorporated herein by reference.
[0005] Some well operations require multiple interventionless openings of the FIV. For example, opening the FIV after setting a packer, pressure testing of the tubing, perforating, flowing of a well for cleaning, and shutting in a well for a period of time.
[0006] Heretofore, there has only been the ability to actuate a FIV remotely and interventionlessly once. Therefore, the interventionless actuator can only be utilized after one operation. Further, if the single interventionless actuator fails it is required to go into the wellbore with a physical intervention to open the FIV. This inflexibility to remotely and interventionlessly open the FIV more than once or upon a failure can be catastrophic. In particular in high pressure, high temperature wells, deep water sites, remote sites and rigless completions wherein intervention with a wireline, slickline, or coiled tubing is cost prohibitive.
[0007] It is therefore a desire to provide a multiple, interventionless actuated downhole valve. It is a further desire to provide a multiple, interventionless actuated downhole valve wherein each actuating mechanism operates independently from other included interventionless actuating mechanisms.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing and other considerations, the present invention relates to remote interventionless actuating of a downhole valve.
[0009] It is a benefit of the present invention to provide a method and apparatus that provides multiple mechanisms for opening a downhole valve without the need for a trip downhole to operate the valve.
[0010] It is a further benefit of the present invention to provide redundant mechanisms for interventionlessly opening a downhole valve if initial attempts to interventionlessly open the valve fail.
[0011] Accordingly, a interventionless actuated downhole valve and method is provided that permits multiple openings of a downhole valve without the need for a trip downhole to open the valve. The multiple interventionless actuated downhole valve includes a valve movable between an open and a closed position to control communication between an annular region surrounding the valve and an internal bore and more specifically controlling communication between above and below the valve, and at least two remotely operated interventionless actuators in operational connection with the valve, wherein each of the interventionless actuators may be operated independently by absolute tubing pressure, absolute annulus pressure, differential pressure from the tubing to the annulus, differential pressure between the annulus and the tubing, tubing or annulus multiple pressure cycles, pressure pulses, acoustic telemetry, electromagnetic telemetry or other types of wireless telemetry to change the position of the valve and allowing the valve to be continually operated by mechanical apparatus.
[0012] The present invention includes at least two interventionless actuators but may include more. Each of the interventionless actuators may be actuated in the same manner or in differing manners. It is desired to ensure that only one interventionless actuator is operated at a time.
[0013] In a preferred embodiment increasing pressure within the internal bore above a threshold pressure operates at least one of the interventionless actuators. In another preferred embodiment an interventionless actuator is operated by a differential pressure between the internal bore and the annular region.
[0014] It should be recognized that varying types of interventionless actuators may be utilized. Some of the possible interventionless actuators are described in U.S. Pat. Nos. 6,550,541; 6,516,886; 6,352,119; 6,041,864; 6,085,845, 6,230,807, 5,950,733; and 5,81 0,087, all to Patel, each of which is incorporated herein by reference.
[0015] The downhole valve has been described as a ball valve, however, other types of valves may be used, such as but not limited to flappers, sleeves, and discs, holding pressure in one direction or both directions. An example of a flapper valve is disclosed in U.S. Pat. No. 6,328,109 to Patel, and is incorporated herein by reference.
[0016] The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein:
[0018] FIG. 1 is an illustration of a wellbore including a downhole valve having multiple, interventionless actuators of the present invention;
[0019] FIGS. 2 a , 2 b , 2 c , and 2 d show a preferred embodiment of the multiple interventionless actuator downhole valve of the present invention; and
[0020] FIG. 3 is an illustration of a rupture disc assembly of the present invention.
DETAILED DESCRIPTION
[0021] Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
[0022] FIG. 1 is an illustration of a wellbore including a downhole valve having multiple interventionless actuators. In FIG. 1 a wellbore 10 having a vertical section and a deviated section is shown. Casing 12 is cemented within at least a portion of wellbore 10 . A production string 14 carrying a downhole valve 16 , shown as a formation isolation valve (FIV), is positioned within wellbore 10 . In one embodiment, FIV 16 includes a ball valve 16 a . Production string 14 and FIV 16 include an internal bore 18 . An annulus 20 is formed outside of FIV 16 that is subject to a pressure outside of the bore 18 .
[0023] A tool 22 , such as a perforating gun, may be run on a tool string 24 , such as coiled tubing, through bore 18 of string 14 and FIV 16 . As and example a shifting tool 26 is connected to a bottom end of tool string 24 . Shifting tool 26 may be utilized singular or in combination with other tools 22 , such as in a sand control application the FIV may be run in the lower completion below or above a screen hanger packer. Shifting tool 26 may be used repeatedly to open and close valve 16 a by running shifting tool 26 through FIV 16 . This is a physical, or intervention actuation of valve 16 a.
[0024] FIV 16 may be actuated from the closed position to an open position by more than one interventionless actuator 28 . Interventionless actuators 28 allow an operator to open valve 16 a without running into wellbore 10 with a shifting tool 26 , thus saving a trip downhole and great expense. As shown in FIG. 1 , FIV includes two interventionless actuators 28 a and 28 b . Each interventionless actuator 28 is independent of the other interventionless actuator 28 . Therefore, it is possible to open FIV 16 more than once without physical intervention. Additionally, multiple interventionless actuators 28 provide redundancy in case an interventionless actuator 28 fails.
[0025] Referring to FIGS. 2 a , 2 b , 2 c , and 2 d , a preferred embodiment of the multiple interventionless actuator downhole valve of the present invention is shown. FIGS. 2 a and 2 b illustrate a first interventionless actuator 28 a . FIGS. 2 b and 2 c illustrate a second interventionless actuator 28 b . FIGS. 2 c and 2 d illustrate a downhole valve 16 .
[0026] With reference to FIGS. 2 c and 2 d downhole formation isolation valve 16 is shown. In a preferred embodiment valve 16 includes a ball valve 16 a that is movable between an open and closed position. Valve 16 includes an operating mandrel 30 functionally connected to ball valve 16 a for moving ball valve 16 a between the open and closed positions. Operating mandrel 30 includes a shoulder 32 .
[0027] Referring to FIGS. 2 a and 2 b a first interventionless actuator 28 a is shown. Interventionless actuator 28 a is an absolute pressure actuator having a housing 34 and first actuator power mandrel 36 . Actuator 28 a includes a first atmospheric pressure chamber 38 and a second atmospheric pressure chamber 40 separated by a seal 42 . A rupture disc assembly 44 is in communication with bore 18 and first atmospheric pressure chamber 38 via a conduit 46 .
[0028] Rupture disc assembly 44 is described with reference to FIG. 3 . Rupture disc assembly 44 includes a tangential port 48 in communication with inside bore 18 and conduit 46 . A rupture disc 50 is positioned between bore 18 and conduit 46 . Therefore, when the inside pressure in bore 18 exceeds a predetermined threshold, rupture disc 50 ruptures, permitting fluid communication between bore 18 and conduit 46 .
[0029] Referring again to FIGS. 2 a , 2 b , 2 c , 2 d , and 3 operation of first interventionless actuator 28 a is described. When it is desired to utilize interventionless actuator 28 a to open valve 16 a of FIV 16 the pressure is increased in bore 18 overcoming the threshold of rupture disc 50 . Rupture disc 50 ruptures increasing the pressure within atmospheric pressure chamber 38 above that of second atmospheric pressure chamber 40 moving first power mandrel 36 downward. First power mandrel 36 contacts shoulder 32 of operating mandrel 30 , moving operating mandrel 30 down opening valve 16 a . The pressure in first and second pressure chambers 38 and 40 equalize and the chambers remain in constant fluid communication allowing valve 16 a to be opened through mechanical intervention. A method and apparatus of achieving constant fluid communication between first atmospheric chamber 38 and second atmospheric chamber 40 is described in U.S. Pat. No. 6,516,886 to Patel, which is incorporated herein by reference.
[0030] Referring to FIGS. 2 b , 2 c and 2 d a second interventionless actuator 28 b is shown. Interventionless actuator 28 b is also a pressure operated actuator. Interventionless actuator 28 b operates based on differential pressure between the inside pressure in bore 18 and an outside pressure in annular region 20 , that may be formation pressure. Interventionless actuator 28 b includes a housing 52 , a second actuator power mandrel 54 , a port 56 formed through housing 50 in communication with the annulus 20 , a spring 58 urges power mandrel 54 downward, and a tension bar 60 holding power mandrel 54 in a set position. Tension bar 60 may be a shear ring or shear screws and our included in the broad definition of a tension bar for the purposes of this description for application as is known in the art.
[0031] Interventionless actuator 28 a is activated by creating a pressure differential between the inside pressure in bore 18 and the outside pressure in annular region 20 . One method of operation is to pressure up in bore 18 thus pushing second actuator power mandrel 54 upward until a predetermined pressure is achieved breaking tension bar 60 . The inside pressure may then be reduced and spring 58 urges power mandrel 54 downward into functional contact with shoulder 32 of operator mandrel 30 opening valve 16 a . The differential pressure between the outside and the inside of bore 18 created by bleeding off the inside pressure in bore 18 assists spring 58 to urge second power mandrel 54 down. Once valve 16 a is cracked open the outside pressure and inside pressure will equalize. Spring 58 continues to urge power mandrel 54 downward. Valve 16 a may be reclosed utilizing a physical intervention.
[0032] Another method of operation includes bleeding inside pressure down in bore 18 creating a lower inside pressure than the outside pressure. Fluid passes through port 56 overcoming the inside pressure and forcing power mandrel 54 downward. When the downward force on power mandrel 54 overcomes the threshold of tension bar 60 , tension bar 60 parts allowing power mandrel 54 to move downward, contacting and urging power mandrel 30 downward opening valve 16 a.
[0033] Embodiments of the invention may have one or more of the following advantages. By using multiple interventionless actuators pressure can be utilized to open the valve more than once while avoiding the need for a trip downhole to operate the valve. Multiple interventionless actuators further provide a redundancy whereby, if one interventionless actuator fails another independent interventionless actuator may be utilized. Even after successfully operating an interventionless actuator the valve can be subsequently opened and closed mechanically by a shifting tool.
[0034] From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a multiple interventionless actuated downhole valve that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow. For example, various materials of construction may be used, variations in the manner of activating each interventionless actuator, the number of interventionless actuators employed, and the type of interventionless actuators utilized. For example, it may desired to utilize an absolute pressure actuator for each of the interventionless actuators or utilized differing types of interventionless actuators. | The multiple interventionless actuated downhole valve includes a valve movable between an open and a closed position to control communication between an annular region surrounding the valve and an internal bore and more specifically controlling communication between above and below the valve, and at least two remotely operated interventionless actuators in operational connection with the valve, wherein each of the interventionless actuators may be operated independently by absolute tubing pressure, absolute annulus pressure, differential pressure from the tubing to the annulus, differential pressure between the annulus and the tubing, tubing or annulus multiple pressure cycles, pressure pulses, acoustic telemetry, electromagnetic telemetry or other types of wireless telemetry to change the position of the valve and allowing the valve to be continually operated by mechanical apparatus. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for forming and moving a yarn reserve in an open-end spinning machine.
Apparatus of the type to which the invention is directed include a spinning turbine or a plurality of parallel-connected spinning turbines and yarn exit openings which are provided with oppositely arranged pairs of delivery rollers. The exit openings are connected in series with a yarn guide rod provided with guide elements and displaceable in a direction transverse to the axis defined by the exit opening and its associated delivery roller pair, the rod forming a deflection device which carries along the yarn coming out of the exit opening.
Spinning turbine machines require an apparatus for forming a yarn reserve because the machine can be restarted only if a yarn reserve can be refed into the spinning turbine within fractions of seconds in order to be connected in the fiber collection trough of the spinning turbine to the ring of fibers formed of fibers just previously fed thereinto.
It is furthermore the custom to displace the yarn coming from the exit opening of the spinning turbine from side to side by a few millimeters. This back-and-forth movement of the yarn prevents the formation of tracks, or grooves in the rubber coating of the pressure roller of the associated pair of discharge rollers.
East German Pat. No. 82,078 describes an apparatus for open-end spinning machines for returning the yarn end into the spinning member during restarting of spinning in which the finished yarn is removed by means of delivery rollers and is wound on a spool. The spinning chamber is followed by a stationary yarn guide, while a further stationary yarn guide is provided in front of the spool. A movable yarn guide is disposed in the region of the delivery rollers between the spinning chamber and the discharge rollers and this yarn guide is movable in the axial direction of the delivery rollers and is provided with a slit as the guide element.
The yarn guide is provided, in addition to the drive for forming and releasing the yarn reserve loop, with a second drive for a back-and-forth movement of the yarn between and transversely of the delivery rollers, both drives being elastically coupled together. While the back-and-forth movement is produced by a motor and a rope pulley disposed on a crank, the reserve force required for the formation of the yarn reserve loop is effected by a magnet.
The drawback of this known apparatus is that the reserve force for the yarn guide is produced by magnets which suddenly move the pulling means which is in connection with the yarn guide. However, the formation of the yarn reserve loop must be effected very slowly since otherwise the yarn could be pulled out of the spinning turbine and may break.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for forming a yarn reserve and for moving the yarn transversely back and forth.
Another object is to provide such apparatus which is as inexpensive as possible.
A further object is to provide such apparatus which permits the dependable formation of a yarn reserve.
These objects are accomplished by providing a yarn guide rod connected with a drive device which is moved only in one direction of rotation and which can be switched off. This drive means produces the back-and-forth movement stroke as well as the reverse stroke required to form the yarn reserve.
In a preferred embodiment of the present invention the yarn guide rod is connected with a gear assembly, via the intermediary of a damping device. The gear assembly is movable by means of a stepping mechanism to deflect the yarn-- against the force of a resetting device connected with the yarn guide rod-- and by releasing a coupling, or clutch, disposed ahead of the stepping mechanism it can be moved to reduce the degree of deflection. The stepping mechanism and the displacement device for the coupling are switched on by means of switching units when a predetermined position of the yarn guide rod with respect to the axis of the exit opening and the pair of delivery rollers has been attained so that the stepping mechanism is actuated or the coupling is released, respectively.
In a further embodiment of the present invention, the yarn guide rod is connected-- when seen from the drive side-- via a toothed rod, with a pair of reduction gears of which the pinion is part of the clutch.
The stepping mechanism preferably includes a pawl which engages in the teeth of a ratchet wheel and which is displaceable in a direction perpendicular to the axis of rotation of the ratchet wheel via a lever and by means of a spring charged magnet. The ratchet wheel is simultaneously provided with a flyback suppressor which prevents rotation of the ratchet wheel in a direction opposite to the movement of the latch.
Thus the present invention substantially includes a switching mechanism of a certain design with which the back-and-forth movement as well as the reserve movement can be effected. During the spinning process the yarn coming from the spinning turbine is moved back and forth and during the slowing down of the spinning machine the yarn reserve required for restarting the machine is formed.
A further embodiment of the invention provides that the toothed rod connected with the yarn guide rod cooperates with a terminal switch associated with the magnet and with a terminal switch associated with the setting device. The magnet terminal switch is adjustable in position with respect to the control surface of the toothed rod when seen in the direction of the lifting stroke produced by the stepping mechanism. The magnet terminal switch is disposed ahead of the terminal switch for the setting device. The damping device advantageously includes a piston which during the resetting movement of the yarn guide rod supports itself in the region of its final position, i.e. in the region of the deflection-free position of the guide rod on a cushion of air.
The movement of the guide rod during resetting which is rapid in the beginning stage is braked in the final stage by a cushion of air enclosed between the piston and the associated cylinder. The resetting device can be easily realized by a biased spring the longitudinal axis of which is offset by 90° with respect to that of the guide rod. This spring is connected with the guide rod via a guide roller mounted at a fixed point and a flexible tension element. Thus, the guide rod is returned to its starting position by the biased spring as soon as the clutch has been released by the influence of the associated terminal switch so that the yarn coming from the exit opening of the spinning turbine is no longer deflected.
The movable component of the clutch is preferably connected with an electromagnet which releases the yarn reserve--i.e. releases the clutch--when it is suddenly excited by means of a rapid switching device. The time required for this purpose is 1/8 to 1/10 of the usual value.
The moment of switching of the rapid switching device is preferably controlled by a counter with a selectable counting time. The counter is coupled with the switch for switching on the spinning machine. The counter is preferably provided with an electronic pulse counter which is connected in series with a speed, path or time controlled pulse generator. The pulse sequence to be counted may be produced, for example, by a magnetically inductive sensor or by RC members.
In a further embodiment of the present invention the pulling magnet terminal switch is coupled to a blocking switch member for the start of the spinning phase and to a blocking switch member for the switch-off phase. The respective terminal switch-- which takes over the unlatching of the back-and-forth stroke-- is rendered ineffective by the two electronic switching members during all of the time under discussion.
A further advantageous embodiment of the present invention provides that the electromagnet for the back-and-forth and the reserve strokes is excited during the spinning phase by a pulse generator with a low pulse repetition rate and during the switch-off phase by a pulse generator with a high pulse repetition rate. The electromagnet is consequently excited to operate at different speeds-- depending upon which pulse generator is effective.
Advisably a timer with a fixed pulse duration is connected in series to the two available electromagnets-- the pulling magnet for the actuation of the movable component of the clutch and the electromagnet for the back-and-forth stroke and for the reserve stroke. The switch-on pulse which drives the magnets is consequently independent of the pulse repetition rate of the associated pulse generator as well as of the switch-on duration of the two terminal switches since the two timers act as electronic limiting stages which also extend shorter pulses to the set pulse duration.
Further significant features and characteristics of the present invention will be explained in detail for the embodiment which is illustrated in the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a and 1b are diagrammatic views showing the position of the yarn guide rod after a back-and-forth stroke or a reserve stroke has been performed.
FIG. 2 is a front elevational view, partly in section, of the drive device for the yarn guide rod.
FIG. 3 is a partial sectional view of the switching gear forming the drive means.
FIG. 4 is a schematic circuit diagram including the switching members required for controlling the yarn reserve formation and the back-and-forth movement.
FIGS. 5a and 5b are function diagrams in which the control processes of the individual switching members (including switching on and switching off) shown in FIG. 4 are plotted over time.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Between a housing 1 which accommodates the spinning turbine and the associated feed devices and the pair of delivery rollers, a yarn guide rod 6 and a connecting piece 7 are disposed. The yarn guide rod 6 is displaceable in a direction perpendicular to the connecting axis 5 of parts 1, 2 and 3. The delivery rollers include feed cylinder 2 and pressure roller 3 disposed thereabove. Both rollers are rotatably mounted in a stationary support 4.
The yarn 8 produced in the spinning turbine is discharged in the direction of arrow 11 through guide tube 9 and exit opening 10 by means of the pair of delivery rollers 2, 3. A known yarn sensor device 12 is disposed between guide tube 9 and exit opening 10 and has a sensor 12' in contact with yarn 8. The yarn sensor device 12 which is schematically illustrated is actuated as soon as the tension of yarn 8 drops due to a break in the yarn in the spinning turbine.
The yarn guide rod 6 is connected at its end opposite the connector 7 with a pretensioned tension spring 15 via a further connector 13 and a tensioning element 14. The lower end of the tension spring 15 is held stationary by the sleeve 16. The longitudinal axis of spring 15 is offset by 90° with respect to the longitudinal axis 6' of the guide rod 6. The force exerted by the spring has its direction changed by means of a guide roller 17 which is supported on a stationary support 17'.
The yarn guide rod 6 is made particularly lightweight in order to reduce its inertia. For example, it can be made of aluminum pipe, a thick aluminum wire or of steel wire. The yarn guide rod 6 is provided with two spaced juxtaposed pins 18 which carry along the yarn 8 passing therebetween and thus deflect it.
The length of path 1 corresponds to the back-and-forth stroke of the yarn guide rod 6 (FIG. 1a). The yarn takes the position 8' shown in dash-dot lines in which it is supported at a stationary support roller 19 which precedes the pair of delivery rollers 2, 3. Instead of the supporting roller some other deflecting means can likewise be used.
After formation of the yarn reserve loop, the yarn guide rod 6 moves toward the right by a further distance L (FIG. 1b) compared to the position shown in FIG. 1a. The yarn discharged through exit opening 10 then takes up the position 8" which is shown in dashed lines in FIG. 1b and in which it forms a partial loop around stationary supporting roller 19. The length of spring 15 has thus been extended to a degree which corresponds to the path traversed by the guide rod (FIG. 1b). The direction of movement of the guide rod 6 during the back-and-forth stroke and during the reserve stroke is shown by arrows 20. The reset movement of guide rod 6 produced by the tension of spring 15 in the direction toward its starting position shown in FIG. 1a (position 8 of the yarn) is shown by arrow 21.
In a modification of the above-described embodiment, the yarn guide rod 6 may be used for the simultaneous deflection of several yarns which are discharged from adjacent spinning turbines by means of their associated delivery rollers. In this case, the guide rod is provided with a corresponding number of adjacent pairs of pins 18.
The connector 7 of the yarn guide rod 6 is screwed to the rod 22 of an attenuation piston 23 disposed in housing 24 (FIG. 2). This piston itself is connected with a toothed rod 25 which is supported on its bottom, which is part of a circle in cross section, by a stationary guide roller 26 (FIG. 3).
The teeth 25' of the toothed rod engage in a toothed gear 27 which is attached to and rotates with a toothed gear 28 having a larger diameter. The shaft 29 carrying gears 27 and 28 is mounted in a support 31 (FIG. 3) via bearings 30. Support 31 also supports guide roller 26. The toothed gear 28 engages an axially displaceable pinion 32 provided with a coupling flange 33. This flange engages in a coupling flange 34 which is immovably mounted with respect to a ratchet wheel 35, which in turn is immovably mounted in the axial direction.
Parts 32 and 33 are supported on a shaft 38 via a slide bushing 36. Shaft 38 is held in bearings 37 and also supports the interconnected parts 34 and 35.
Ratchet wheel 35 is moved in clockwise direction by means of a pawl 39 having a toothed head 39' which engages in the teeth 35' of part 35. Pawl 39 is supported in a bore 39" having a spherical surface on a pin 40 which is fastened to a lever 41. This lever is held in a fulcrum 42 via a welded-on bushing 42'. The freely movable end of lever 41 is connected, via a joint 43, with a spring biased electromagnet 44 which is stationarily mounted above lever 41. The spring returns the movable piston 44' of the pulling magnet into its upper end position.
One side of pawl 39 is held in a guide 45. Rotation of the ratchet wheel in the opposite direction, i.e. counterclockwise, is prevented by a blocking bar 46 serving as a flyback suppressor which is pivoted about a pivot point 47. The bar 46 has a head 46' which engages in the teeth 35' of ratchet wheel 35. Head 46' is pressed against the teeth of ratchet wheel 35 by a tensioned helical spring 48.
The coupling flange 33 is axially displaced by means of an electromagnet 49 which is connected with a lever 51, via a joint 50, and through lever 51 with a double lever 52 which is rotatably mounted on pin 42. This double lever 52 engages, by means of trunnion 53, into bushing 54 which is supported via roller bearings 55 on the extension of the displacement pinion 32. The electromagnet 49 is designed so that the parts 33 and 34, which constitute the clutch, are disengaged only when the electromagnet is switched on, i.e. when the associated coil is energized. In this case the clutch is opened by moving part 54 toward the left, i.e. by pivoting the dual lever 52 in clockwise direction.
The electromagnet 44 which drives the ratched wheel 35 is connected to be controlled by a terminal switch 56 which has a switching contact 56' actuated via control surface 25" of toothed rod 25. Terminal switch 56 is advisably displaceable in the direction of arrows 57. The electromagnet 49 is controlled via a terminal switch 58 which is disposed behind terminal switch 56 when seen in the direction of the displacement movement indicated by arrow 20.
The operation of the apparatus according to the present invention will be explained in connection with FIGS. 4, 5a and 5b. The control operations associated with the individual switching members (FIG. 4) are shown in the function diagrams of FIGS. 5a and 5b with a position supplemented by the index f.
When the spinning machine has been switched on by the start or spinning key 61 or 62, respectively (function diagram 61f and 62f), which are part of the apparatus, an electronic store 63 (function diagram 63'f) is set. After a certain time--which is of no significance in this connection--timer 64 (64f) sets a further store 65 (65f) which causes a pulse generator 66 to emit a sequence of pulses 66f which are counted by an electronic counter 67 according to a certain code. The pulse sequence may here be produced in a known manner dependent on the path, the speed, or on time.
A preselect switch 68 interrogates a pulse 68f which it defines. When this certain number of pulses has been reached, a memory 69 (69f) is set which is erased again after further pulses by an AND gate 70 (function diagram 69f, 70f). The AND gate also erases store 65 (65f) and activates timer 71 which effects switching from starting-to-spin to the spinning speed of the machine (71f).
The setting of store 69 activates a timer 72 with fixed pulse duration 72f. These pulses control, via amplifier 73, a rapid switch-on device 74 which excites electromagnet 49 in about 1/8 to 1/10 of the normal setting time (49f), in that the coil of magnet 49--which is designed for a direct voltage of 24 volts--temporarily receives a voltage of 220 volts.
Magnet 49 thus displaces coupling flange 33 (FIG. 3) to the left until toothed gears 32, 28 and 27 are freely movable and the biased spring 15 (FIG. 1) consequently can move the yarn guide rod 6 with the yarn passing thereover into the operating position (unlatched position) over path L. This releases the yarn reserve to start spinning. The reset movement is braked by attenuation piston 23 (FIG. 2). In the vicinity of its left-hand end position, this piston covers a bore 60 in housing 24 so that a cushion of air is locked within the housing thus preventing sudden banging of piston 23 on the frontal face 24'.
After expiration of the time set by timer 71 (71f), the blocking of NOT-OR gate 75 (75f) is released so that the further unlatching of the yarn guide rod 6 by means of electromagnet 49 depends only on actuation of the terminal switch 56 (56f) by control surface 25" (FIG. 2). Store 69 (69f) is no longer able to emit a pulse once it has been erased.
Simultaneously with switching from start-to-spin to the spinning speed, timer 71 (71f) cancels the block on pulse generator 76, the pulses 76f from which may be considerably decreased (e.g. one pulse per minute). The pulse sequence may be produced in the same manner as discussed for pulse generator 66.
With every pulse a timer 77 is activated which emits a switching pulse 77f of a defined duration (e.g. 0.2 seconds) to an amplifier 78. This amplifier excites pulses uniformly in pulling magnet 44 (44f) so that the ratched wheel 35 is switched on by one step (FIGS. 2, 3).
The movement of the ratchet wheel in the direction of arrow 59 is transmitted through the meshed coupling flanges 33 and 34, pinion 32, and toothed gears 28 and 27, so that the toothed rod 25 and the attenuation piston 23 are pulled toward the right in the direction of arrow 20 and thus also the yarn guide rod 6--in correspondence with the existing transmission ratio. Reverse rotation of the meshing parts is prevented by the lock 46.
As soon as the toothed rod 25 has moved to the right to the point where its control surface 25" has displaced the switching contact 56' of terminal switch 56 in the direction of its longitudinal axis, the series-connected NOT-OR gate 75 emits a pulse 75f to the second input 72' of the timer 72 and thus again disengages the yarn guide rod 6 by exciting magnet 49 so that the back-and-forth stroke 1 is again performed. Since spring 15 is only slightly tensioned at this point, the resetting forces acting on guide rod 6 are slight. The back-and-forth movement is continued until the spinning machine has been switched off by actuation of key 79 (79f). This key sets memory 80 and its output 80' blocks pulse generator 76 (76f) for the slow pulse sequence-which was required for the back-and-forth stroke--and releases another pulse generator 81 for a fast pulse sequence 81f (e.g. a pulse duration of 0.5 seconds) with its output 80" (80"f). At the same time store 80 blocks, with its output 80' (80'f), the NOT-OR gate 75 (75f) so that the terminal switch 56 (56f) becomes ineffective. The toothed rod 25 can now move rapidly beyond terminal switch 56--as a result of the fast pulse sequence 81f from pulse generator 81 to timer 77 which brings the duration of the pulses to the same value as during the back-and-forth stroke, and as determined by amplifier 78 and the magnet 44 controlled thereby. This occurs until the control surface 25" shifts switching contact 58' of terminal switch 58 (58f). This terminal switch thus blocks pulse generator 81 (81f) so that magnet 44 (44f) is made inoperative and releases a switch-off program 82 which comprises three steps as follows: (1) reducing the speed of the spinning device to about 30% of normal working speed; (2) shutting off sliver delivery and braking down yarn winding; and (3) switching off the entire device. After this stores 63 (63"f), 71 and 80 are erased via a line 83 (83f).
The path L traversed to form the yarn reserve can be set by shifting terminal switch 58. When the machine is restarted, the yarn reserve must be released in fractions of seconds--thus the use of the very precisely operating pulse generator 66 and rapid switch-on device 74. In order for the reset movement to take place without delay, housing 24 is provided with one or more bores 60 through which the air impeding the reset movement can be expelled. The piston is braked only in the vicinity of frontal face 24' and thus sudden banging of the piston--produced as a result of the high bias of spring 15 from its greater deflection--is avoided.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | Apparatus for forming a yarn reserve and for moving yarn back and forth in open-end spinning devices. This type of device has at least one spinning turbine, a yarn delivery opening, and a pair of delivery rollers opposite the opening. A yarn guide rod has guide elements and is located downstream of the delivery opening in the direction of yarn movement. The yarn guide rod is displaceable in a direction transverse to the axis between the opening and the delivery rollers. This rod defines a deflection device for diverting the yarn from the axis. A drive is provided for driving the yarn guide rod and is in interruptable connection therewith. The drive moves the guide rod back and forth and moves the guide rod to a further position for providing a yarn reserve. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a flexible, alloyed, polyvinyl chloride (PVC) resin film, also referred to simply as PVC/alloy film, which is coated with an acrylic stain resistant coating. The coated film resists staining, is oil and grease resistant and is easily cleanable. Combining the PVC/alloy film with the stain resistant acrylic coating gives superior oil and stain resistance than either the film or coating on its own. The coated film can be post laminated to various fabric substrates.
2. Description of the Related Art
PVC/alloys have been in existence for some time. PVC/NBR (acrylonitrile-butadiene rubber) alloys are used in automotive dash boards and door panels.
Flexible PVC is laminated to various fabric substrates for use in upholstery, boat and machinery covers, table clothes, etc. These products do not last very long because dirt and stains are not cleanable from the vinyl surface. Oil and greases also extract plasticizer from the vinyl causing embrittlement and even cracking. There has been a long search for materials that will increase the useful life of the laminated vinyl.
Currently, flexible PVC laminated fabric products consist of monomeric plasticized PVC film coated with a vinyl, vinyl/acrylic or urethane topcoat. Staining agents migrate through the coating and into the plasticizer of the PVC film. This creates a permanent stain. Stain resistant products currently on the market are only marginally more effective than conventional plasticized PVC coated products.
SUMMARY OF THE INVENTION
The present invention comprises a flexible PVC/alloy film coated with an acrylic stain resistant coating having sufficient flexibility for the intended application of the coated film. Briefly, this invention involves the formation of a base film by alloying PVC resin with an acrylonitrile-butadiene copolymer rubber (NBR) for interior applications or alloying the PVC resin with an ethylene-n-butyl acrylate-carbon monoxide polymer for exterior applications. The alloyed film is then coated with an acrylic coating of: (1) polymethyl methacrylate (homopolymer) for end uses such as wall coverings which normally do not require high flexibility such as frequent creasing; or (2) the polymethyl methacrylate together with flexibilizing polymers such as a methyl methacrylate copolymer and/or a vinyl chloride-vinyl acetate copolymer for applications requiring more flexibility or creasing. One application requiring extensive flexibility and creasing is that of seat cushions wherein the flexibilizing polymer is preferably a copolymer of methyl methacrylate with a alkyl acrylate, a vinyl chloride-vinyl acetate copolymer; or mixtures thereof.
One embodiment of the invention involves the above described coated film.
Another embodiment of the invention involves the above described coated film laminated to a fabric substrate.
The base film is a formulation which provides for low migration which resists oil and grease penetration. The acrylic topcoat works synergistically with the base film to improve stain resistance and cleanability. The useful life of the vinyl product/fabric is greatly extended by this invention.
One of the important problems solved by this invention is inhibiting or preventing plasticizer migration by use of the alloying materials and polymeric plasticizers with PVC resin.
DETAILED DESCRIPTION OF THE INVENTION
The invention of this application incorporates a two phase approach for making flexible PVC resin stain and oil resistant. Both approaches combine to give excellent oil resistance, stain resistance and cleanability. Phase I involves an oil resistant flexible PVC resin base film. This is done by alloying PVC resin with acrylonitrile-butadiene copolymer rubber for interior products or alloying PVC resin with ethylene-n-butyl acrylate-carbon monoxide polymer for exterior products.
Phase II involves applying a polymethyl methacrylate coating to the PVC/alloy base film. This acrylic coating exhibits excellent UV properties and stain resistance. The combination of Phase I (PVC/alloy) and Phase II (antistain coating) produce a product with superior oil and stain resistance as well as improved cleanability.
The PVC resin for the base film is preferably that of a high molecular weight PVC resin, i.e., one having a molecular weight of about 115,000 to 150,000 or a mixture of high molecular weight PVC resin and up to about 50% by weight, preferably from about 5% to 40% by weight of an ultra high molecular weight PVC resin, i.e., one having a molecular weight of at least 185,000 such as from about 185,000 to 225,000, e.g., OXY 410 of the Occidental Chemical Corporation.
The polyvinyl chloride resin used in the base film of the present invention will have a vinyl chloride unit content of at least 90% by weight, preferably at least 95% by weight and includes homopolymers of vinyl chloride, copolymers of vinyl chloride with ethylenically unsaturated monomers copolymerizable therewith and mixtures thereof. Polyvinyl chloride polymers prepared by emulsion polymerization, suspension polymerization, or bulk polymerization may be used in the present invention. The ethylenically unsaturated comonomers copolymerizable with vinyl chloride may be a variety of known compounds. Typical examples include olefinic compounds such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated carboxylic acids and the esters or amide thereof such as acrylic acid, methacrylic acid, methyl acrylate, etc.
The ultra high molecular weight PVC resin acts as a processing aid in the alloyed base film and makes the surface of the film less tacky and duller. Additionally, it improves thermal resistance.
Conventional polymeric plasticizers can be used in the PVC film of this invention. Polymeric plasticizers are condensation products of polyhydric alcohols, e.g. glycols, and dibasic organic acids. Illustrative of the polyhydric alcohols there can be mentioned 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, etc. Illustrative of dibasic acids there can be mentioned sebacic acid, azelaic acid, adipic acid, etc.
Conventional monomeric plasticizers for PVC can optionally be used in this invention. Illustrative of monomeric plasticizers there can be mentioned: phthalic acid esters such as dibutyl phthalate, dioctyl phthalate, diisodecyl phthalate, diisoundecyl phthalate, etc.; trimellitic acid esters such as trioctyl trimellitate, tri-2-ethylhexyl trimellitate, tridecyl trimellitate, etc.; adipic acid esters such as dioctyl adipate, diisodecyl adipate, etc.; phosphoric acid esters such as tricresyl phosphate, trioctyl phosphate, etc; epoxy plasticizers and liquid polyesters. The preferred monomeric plasticizers are those of the phthalic acid esters and adipic acid esters, particularly those wherein each of the hydrocarbyl substituents on the phthalate or adipate are straight chain alkyl groups having at least 7 carbon atoms such as that of 7 to 11 carbon atoms.
The compositions can also include processing aids such as acrylic processing aids. The quantity of processing aid, when used, will vary from about 0.5 to 10 parts for each 100 parts of PVC resin.
The base film formulation will generally include conventional additives such as antioxidants, ultra violet (U.V.) absorbers, costabilizers, lubricants, silica gloss reducing agents, pigments and fillers.
The key ingredients in the PVC base film are: (1) the alloying materials of either acrylonitrile-butadiene rubber (NBR) or ethylene-n-butyl acrylate-carbon monoxide polymer; (2) a polymeric plasticizer; and (3) optionally monomeric plasticizer. The ratio of alloy/polymeric plasticizer can be varied to modify the oil resistance and the flexibility of the film. The quantity of such ingredients can vary over a wide range.
The quantity of the NBR or ethylene-n-butyl acrylate-carbon monoxide alloy material will preferably vary from about 10 to 50 parts and particularly 20 to 40 parts per one hundred parts (PHR) of the PVC resin. The quantity of polymeric plasticizer will preferably vary from about 10 to 60 parts and particularly 20 to 50 parts for each 100 parts by weight of the PVC resin. The use of monomeric plasticizer such as DIDP (diisodecyl phthalate) is optional but can be used in quantities of up to about 50 parts such as 5 to 40 parts per one hundred parts of the PVC resin.
The acrylonitrile-butadiene rubber in the base film, when used, will normally contain from 15% to 50% of acrylonitrile, by weight, and preferably about 25% to 40% by weigh of acrylonitrile based on the weight of the rubber with the remainder of the rubber being the butadiene.
Conventional heat stabilizers can be employed in the PVC base film. Thus, the stabilizer can be a salt of a carboxylic acid with a metal such as barium, tin, calcium, magnesium, zinc or the like either individually or in combination. Also, the stabilizer can be an organic ester of phosphorous acid or the like and combinations of such ester with a carboxylic acid salt. The total quantity of heat stabilizer can vary over a broad range such as from 1 to 6 parts by weight based on each 100 parts of PVC resin.
The PVC resin can contain costabilizers such as epoxy compounds, e.g., epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, butyl ester of epoxidized linseed oil fatty acid, butyl or 2-ethylepoxystearate, and the like. The quantity of costabilizer, when used, can vary from about 1 to 15 parts based on each 100 parts of PVC resin.
The acrylic stain resistant topcoat of this invention offers superior stain resistance as compared to conventional vinyl, vinyl/acrylic or urethane coatings. In cases where high flexibility is not required, such as for use in wall coverings, polymethyl methacrylate (homopolymer) can be used alone as the top coat. However, for more flexible applications such as seat covers and other upholstery uses which may involve creases and folds in the product, the addition of a flexibilizing methyl methacrylate copolymer, a flexibilizing PVC-vinyl acetate copolymer or mixtures thereof to the polyvinyl methacrylate impart more flexibility to the coating. Such flexibility avoids cracking of the top coat. Such top coat creates a coating that is stain resistant yet flexible enough to adhere properly to the PVC alloy sheet.
The key ingredient in the coating is polymethyl methacrylate homopolymer. However, to increase flexibility, a flexibilizing polymer for the polymethyl methacrylate is added to the coating formulation. Illustrative of flexibilizing polymers there can be mentioned: various copolymers of methyl methacrylate, vinyl copolymers, and low molecular weight PVC homopolymers.
The vinyl chloride-vinyl acetate flexibilizing copolymer in the top coat, when used, will normally contain from about 5% to 20% of vinyl acetate, and preferably about 7% to 15% with the remainder of the copolymer being the vinyl chloride.
The flexibilizing methyl methacrylate copolymer can be a copolymer of methyl methacrylate with from about 5% to 50% by weight of the copolymer and preferably 10% to 40% thereof of: (a) a medium to long chain alkyl methacrylate such as one having about 4 to 10 carbon atoms in the alkyl group, e.g. a copolymer of methyl methacrylate and n-butyl methacrylate or 2-ethylhexyl methacrylate; or (b) an alkyl acrylate such as one having up to about 10 carbon atoms in the alkyl group, e.g. a copolymer of methyl methacrylate and ethyl acrylate.
The low molecular weight PVC homopolymer used as a flexibilzer can be one such as V-95 which is supplied by Borden, Inc. having a molecular weight range Mw of 80,000 to 100,000.
The concentration of the flexibilizing polymer, when used, can vary over a broad range such as up to 75% of each flexibilizing polymer by weight of the polymethyl methacrylate homopolymer, provided that the polymethyl methacrylate homopolymer is at least 50% by weight of the solid polymeric materials in the coating. Preferably the quantity of each flexibilizing polymer will vary from about 5% to 25% based on the weight of the polymethyl methacrylate homopolymer. The various flexibilizing polymers can be used in the top coat either alone/or in combination.
The polymethyl methacrylate (homopolymer) should make up at least 50% by weight of the polymeric materials in the solid coating, preferably at least 60%.
Conventional ultra violet (U.V.) light absorbers can be used in the base film and coating of this invention. Such U.V. absorbers can be that of a benzotriazole compound, benzophenone compound, or a hindered amine compound and specifically includes 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole; 2-(3,5-di-t-butyl-2-hydroxyphenyl)- 5-benzotriazole; polycondensate of dimethyl succinate with 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, various 2-hydroxy-4-alkoxybenzophenones, e.g., 5,5'-methylenebis(2-hydroxy-4-lauroxybenzophenone), 5,5'-methylenebis(2-hydroxy-4-octoxybenzophenone), and the like. The quantity of U.V. absorber, when used, will generally vary from 0.1 to 1 part for each 100 parts, by weight of the PVC resin.
Preferred formulations for this invention are shown below.
PHASE 1 PVC/ALLOY FILM
______________________________________ Supplier Parts/wt______________________________________Formulation I (Interior)High molecular weight PVC (VC106) (1) 100Acrylonitrile-butadiene copolymer (2) 40rubber (HYCAR 1422 X14) (NBR)Epoxidized soybean oil (DRAPEX 6.8) (3) 3Polyester plasticizer (DRAPEX P1) (3) 30Plasticizer (DIDP-diisodecyl phthalate) 28.5barium zinc liquid stabilizer (MARK 4753) (3) 2.5acrylic process aid (ACRYLOID K120N ) (4) 1.5Acrylic dulling agent (ACRYLOID KF710) (4) 2polyethylene lubricant (AC# 617A) (5) 0.5pigmentation as requiredcalcium carbonate 20Formulation E (Exterior)High molecular weight PVC (VC106) (1) 100Ethylene-n-butyl acrylate-carbon monoxide (6) 30(ELVALOY HP)Epoxidized soybean oil (DRAPEX 6.8) (3) 3Polyester plasticizer (DRAPEX P1) (3) 25Plasticizer (DIDP-diisodecyl phthalate) 25Barium zinc liquid stabilizer (MARK 4731) (3) 2.5Acrylic process aid (ACRYLOID K120N ) (4) 4Acrylic dulling agent (ACRYLOID KF710) (4) 2Antioxidant (IRGANOX 1010) (7) 0.5Ultraviolet stabilizer (MARK 1413) (3) 0.3Polyethylene lubricant (AC# 617A) (5) 0.5Pigmentation as requiredCalcium carbonate 20Biocide (VINYZENE BP5-5) (8) 1.5______________________________________
PHASE II--STAIN RESISTANT COATING
A typical solution of a stain resistant coating which can be applied and dried on to the base film is shown below.
______________________________________Polymethyl methacrylate homopolymer (6) 10.5(ELVACITE 2010)Methyl methacrylate-ethyl acrylate (4) 2.6copolymer (ACRYLOID B82)Vinyl chloride/Vinyl acetate Copolymer (VC171) (1) 4.4Cellulose Acetate Butyrate (CAB 0.5) (9) 0.5Silica Dulling Agent (SYLOID 234) (10) 1.8Ultra Violet Stabilizer (SANDOZ VSU) (11) 0.2Solvent (Methylethyl Ketone) 80.0TOTAL 100.0______________________________________
SUPPLIERS OF THE INGREDIENTS OF THE ABOVE PVC/ALLOY FILM AND THE STAIN RESISTANT TOPCOAT
(1) Borden Chemicals & Plastics
(2) Zeon Chemicals Inc.
(3) Witco, Inc.
(4) Rohm and Haas
(5) Allied Chemical
(6) Dupont
(7) Ciba Geigy
(8) Morton International
(9) Eastman Chemical
(10) W. R. Grace
(11) Sandoz
The preferred method for preparing the flexible PVC/alloy film and its coating is described below:
A. A steam-heated ribbon blender is charged with 3,600 pounds of compound by sequential addition of ingredients, except for the ethylene-n-butyl acrylate-carbon monoxide polymer in the case of the exterior formulation, of the Phase I alloy film in the appropriate ratios. The blender is operated at approximately 175° F. for 20 minutes or until the compound appears dry.
B. The dry compound is than dropped in batches of approximately 160 pounds into a banbury mixer. In case the alloy is ethylene-n-butyl acrylate-carbon monoxide polymer, this polymer is added directly to the banbury by stepwise addition to insure proper dispersion. The compound is fluxed and masticated within the banbury for 5 minutes. The pigmentation is fluxed with the compound in this step. At a temperature of about 350° F. the globular plastic batch is dropped onto a two-roll mill and is then fed onto a two-roll feedmill. The dwell time of the material in the two-roll mill is dependent upon the speed of the calender and the banbury drop frequency. The mills are heated at 350° F.
C. From the feed mill the material is run into an extruder which extrudes a "rope" onto a conveyor which deposits the material between the No. 1 and No. 2 rolls in the top of the calender. These calenders are the inverted "L" type. The No. 1 and No. 2 rolls are parallel to each other arranged horizontally. Roll No. 3 is directly beneath and parallel to Roll No. 2 and Roll NO. 4 is beneath roll No. 3. The rolls are oil heated to 370° F. for rolls No. 1 and No. 2, 399° F. for Roll No. 3 and 345° F. for roll No. 4. The calender is adjusted so that the sheet emerges with the correct thickness. Thicknesses of 0.004 inches to 0.020 inches are most common for this sheet. The sheet is sent through an embossing station, a series of cooling cans, an accumulator and finally to a winder. The final sheet is wound into rolls for subsequent printing, coating and lamination to fabric.
D. The film is than printed and or coated using the stain resistant coating. The coating is applied via the rotogravure process. The engraved roller of choice is a 100 line quadrangle configuration with a cell depth of 0.0040 inches. The coated web is dried using a series of high impingement air nozzles at a temperature of 120° F.
E. The coated film is then laminated to fabric substrate using a vinyl plastisol adhesive. The fabrics of choice are polyester non wovens (3.0-6.0 ounces per square yd) or polyester weft insertion warp knits. Three ply constructions are preferred when using the weft insertion warp knits. The film thickness of a three ply construction can be that of 0.003 to 0.02 inches whereas that of the two ply construction can be from about 0.004 to 0.02 inches thick. The constructions are as follows:
______________________________________3 ply 2 ply______________________________________Antistain Topcoat Antistain TopcoatPVC/Alloy film PVC/Alloy FilmVinyl Plastisol Adhesive Vinyl Plastisol AdhesivePolyester Weft Insertion Warp Knit Polyester Non WovenPVC/Alloy Film______________________________________
The following examples are illustrative of the invention and its advantageous properties. In these examples, as well as elsewhere in this application, all parts are by weight unless otherwise indicated.
EXAMPLE 1
Samples of PVC/alloy Formulation I (Interior) as shown above were coated in the laboratory using the antistain coating. The coating was prepared on a laboratory homogenizer and applied to the PVC/alloy film I (Interior) using a #12 wire wound draw down bar. The coating was dried for 1 minute at 200° F. in a forced hot air oven. Staining agents were applied to the coated product and allowed to stand for 30 minutes. The staining agents used were red lip stick, ball point pen, permanent marker and "Frenches" yellow mustard, After the 30 minutes aging the stains were cleaned off using a 3 step process which consisted of: Step 1--Warm tap water; Step 2--"Fantastic" liquid cleaner; and Step 3--Isopropyl alcohol (rubbing alcohol).
Results: All four stains cleaned completely off the experimental product while a conventional product and competitive PREFIX material of GEnCorp Fabricated Plastics Division of GenCorp Polymer Products Co. left deep noticeable stains. The conventional product formulation for the base film referred to in these examples was as follows:
______________________________________Ingredient Parts by Weight______________________________________(A) FORMULATION FOR THECONVENTIONAL BASE FILMPVC Resin 100Calcium carbonate 20Epoxidized soy bean oil 3Phthalate plasticizer (DINP) 78Barium-zinc liquid stabilizer 2Acrylic process aid (Acryloid Kizon) 1.5Stearic acid lubricant 0.4Pigmentation As required(B) FORMULATION FOR THECONVENTIONAL TOPCOATVinyl chloride/vinyl acetate resin (VC 171) 15.0Polymethyl methacrylate homopolymer 3.8(ELVACITE 2010)Cellulose acetate butyrate (CAB 0.5) 0.6Epoxidized soybean oil (EPO) 0.6Methyl ethyl ketone 80Total 100______________________________________
EXAMPLE 2
PVC/alloy I (Interior) as shown above was coated using the antistain topcoat shown in the Phase II formulation above. The coating was applied using a 100 line quadrangle engraved roller. The coating deposition was approximately 0.02 pounds dry/linear yard (54 inches). The coating was applied to the PVC/alloy film on a 6-color rotogravure printer. This material was then laminated to 4 ounce polyester non woven fleece. The finished fabric was tested for stain resistance to red lipstick, ball point pen, permanent marker and Frenches yellow mustard. Stain resistance was tested for 30 minutes and also for 9 days.
Results: All stains cleaned off completely even after 9 days aging. This performance far exceeded all other products tested.
EXAMPLE 3
Samples of PVC/alloy formulation E (Exterior), as shown above, were prepared in the laboratory on a 2 roll mill and coated with the stain resistant coating of the Phase II formulation shown above using a #12 wire wound bar. Staining agents were applied and cleaned off after 30 minutes as specified in EXAMPLE 1.
Results: All four stains cleaned completely from the experimental product. Accelerated weathering studies on this PVC/alloy formulation E (Exterior) showed no discoloration after 500 hours in a Q-U-V weatherometer using UVB-313 bulbs. The PVC/alloy formulation I (Interior) discolored after 100 hours. The Q-U-V weatherometer is manufactured by Q Panel Company of Cleveland, Ohio and the UVB-313 bulbs are known for their aggressive ultra violet radiation.
EXAMPLE 4
A series of comparative tests were performed with five different products using various base films and coatings to determine stain resistance. The staining agents used were red lip stick, ball point pen (blue), permanent marker, and "Frenches" yellow mustard. Stain resistance was tested for 30 minutes and also at 7 days. The staining agents were removed using a three stop process of warm tap water, "Fantastic" liquid cleaner, and isopropyl alcohol. The five products which were tested are described below:
Product 1. This was a conventional monomeric plasticized PVC base film without topcoat. The formulation of the base film was the same as that of the conventional product formulation used as a comparison in EXAMPLE 1.
Product 2. This was the preferred Formulation E (Exterior) which is described above and which was also used in EXAMPLE 3 but the topcoat was not applied to the film.
Product 3. This was the conventional PVC base film used in Product 1 but it was coated with the PHASE II STAIN RESISTANT COATING set forth hereinabove in the preferred formulations,
Product 4. This was the preferred vinyl alloy Formulation E (Exterior) as used in Product 2 but with a conventional dried vinyl coating from the following wet formulation:
______________________________________Ingredient Parts by Weight______________________________________Vinyl chloride/vinyl acetate 15.4copolymer (VC 171)Polymethyl methacrylate 3.8homopolymer (ELVACITE 2010)Cellulose Acetate Butyrate 0.6(CAB 0.5)Epoxidized soybean oil 0.2(DRAPEX 6.8)Solvent (methyl ethyl ketone) 80.0Total 100.0______________________________________
Product 5. This was vinyl alloy Formulation E as in Products 2 and 4 with the same antistain coating as in Product 3.
The results of these tests is shown below for the 30 minute test and for the 7 day test.
______________________________________Product______________________________________ 30 Minute Test1. Severe stains left from all staining agents.2. Moderate stains from pen, marker and mustard.3. Moderate stains from pen and marker.4. Moderate stains from pen and marker.5. All four stains cleaned off completely. 7 Day Test1. Severe staining left from all staining agents.2. Moderate staining left from all staining agents.3. Severe staining left from all agents.4. Moderate staining left from all agents.5. Very slight staining left from the permanent marker whereas the other stains cleaned off completely.______________________________________
It can be seen from the above tests that the alloy/stain resistant coating system of this invention clearly out performs the additive effect of its component parts. | A stain resistant, easily cleanable and flexible plastic coated film comprising a base film and a coating thereon wherein the base film comprises a polyvinyl chloride resin, a polymeric plasticizer, and a member selected from the group consisting of acrylonitrile-butadiene copolymer rubber and ethylene-n-butyl acrylate-carbon monoxide polymer and the coating comprises polymethyl methacrylate alone or together with a flexibilizing polymer such as vinyl chloride-vinyl acetate copolymer and/or a flexibilizing copolymer of methyl methacrylate. The coated film gives superior oil and stain resistance as compared to the base film or coating alone. | 1 |
FIELD OF INVENTION
This invention relates generally to LED lighting assemblies for a merchandise display and methods of lighting. In particular, in one aspect of the invention, an LED light assembly is provided with various lenses to capture the light from LED emitters so as to modify their beam patterns, and re-project the light to provide an even distribution of the light in a vertical plane.
BACKGROUND
In many retail stores it is desired to illuminate the front of product packages on merchandise display shelves to improve the product presentation, shopping environment, and to highlight products to ultimately improve the overall sales of the products.
Typically, this is accomplished with a fluorescent lighting fixture, which is located above a shelving unit and emits light down upon the front of the shelves. However, in most existing installations of this type, much of the light is not used because it is not captured and directed to the front of the shelves. Lack of focusing, specific reflectors, or beam modification results in product on higher shelves being too brightly illuminated and product on lower shelves receiving very little light at all.
Additionally, there are also significant costs with replacing lamps on fluorescent fixtures when they deteriorate or burn out including the costs of new lamps and labor to replace the lamps. In addition, when the lamps are replaced on the scale of a large retail chain, replacement can become environmentally harmful since all fluorescent lamps contain mercury.
In one exemplary aspect of the present invention, more of the available light is directed to the front of products merchandised on a shelf and a higher illuminance per watt of power is output than with existing fluorescent fixtures. In another exemplary aspect of the present invention, a lower cost lighting solution is disclosed that uses less energy, directs and improves the illumination on the product packages, particularly on the lower shelves, and requires lower maintenance costs.
SUMMARY
The following presents a general summary of aspects of the invention in order to provide a basic understanding of the invention and various features of it. This summary is not intended to limit the scope of the invention in any way, but it simply provides a general overview and context for the more detailed description that follows.
In one exemplary embodiment, a lighting assembly for a merchandise display is disclosed. The lighting assembly can comprise a circuit board assembly having a plurality of LEDs and an LED driver circuit and an integral lens assembly. The integral lens assembly can comprise a plurality of lenses. The plurality of lenses can be placed over a corresponding one of the plurality of LEDs allowing the lenses to capture the light from a respective LED, modify the beam pattern, and re-project the light.
In another exemplary embodiment, a lighting method for a merchandise display is disclosed. The method can comprise arranging a plurality of LEDs and a LED driver circuit on a circuit board and, securing a plurality of lenses to the circuit board, placing the plurality of lenses over a corresponding one of the plurality of LEDs so as to capture the light from a respective LED, modify a beam pattern emitted from the respective LED, and re-project the light emitted from the respective LED.
Other objects and features of the invention will become apparent by reference to the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention and certain advantages thereof may be acquired by referring to the following detailed description in consideration with the accompanying drawings, in which:
FIG. 1 shows a perspective view of exemplary lighting assemblies in use on a merchandise display;
FIG. 2 shows another perspective view of exemplary lighting assemblies;
FIGS. 3A and 3B show top views of an exemplary circuit board assembly contained in the lighting assemblies; and
FIG. 4 shows a perspective view of the exemplary circuit board assembly.
FIG. 5 shows a top view of another exemplary circuit board assembly contained in the lighting assemblies
The reader is advised that the attached drawings are not necessarily drawn to scale.
DETAILED DESCRIPTION
In the following description of various example structures in accordance with the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration of various structures in accordance with the invention. Additionally, it is to be understood that other specific arrangements of parts and structures may be utilized, and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top” and “bottom” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the Figures and/or the orientations in typical use. Nothing in this specification should be construed as requiring a specific three dimensional or spatial orientation of structures in order to fall within the scope of this invention.
FIGS. 1 and 2 depict exemplary LED lighting assemblies 10 for a merchandise display. As shown in FIGS. 1 and 2 , the LED lighting assemblies 10 each include a housing 12 , a circuit board assembly 24 , and a circuit board 16 having an LED driver circuit 22 (shown in FIG. 3B ). The housing 12 can include a series of clamps 28 for securing the housings above the area being illuminated. A plurality of LED emitters 20 are mounted to the circuit board 16 and are powered with the LED driver circuit 22 . As shown in FIG. 4 , the LEDs are spaced apart from each other along the circuit board assembly 24 . The circuit board assembly 24 is also connected to a power cord 18 .
The lenses 14 can be secured over individual LED emitters 20 to provide different refractive properties for reflecting the light emitted by the LEDs in various angles and directions such as over product shelves. As shown in FIGS. 3A and 3B , the lenses 14 can be provided with different refractive configurations. However, alternatively, the lenses can all be provided with the same refractive configurations. In another alternative embodiment, the lenses may be placed over ever other LED to modify the light pattern. Other arrangements are also contemplated to provide optimal lighting properties and configurations depending on the environment and desired results.
In one exemplary embodiment, as shown in FIGS. 3A and 3B , the lenses are provided with a spotlight beam refractive surface 15 A and an oval beam refractive surface 15 B. The light emitted from the spotlight pattern 15 A lenses on the circuit board assembly 14 is directed at the lowest point such as a product on the bottom shelf, whereas the light emitted from the oval pattern 15 B lenses is directed at the upper and middle areas such as at products on the top and middle shelves. When in use in the lighting assembly, the different refractive surfaces or lens types (spotlight pattern 15 A and oval pattern 15 B) project the light in various directions such that the individual patterns in aggregate from all LED emitters, result in light more evenly distributed in a vertical plane such as over products and shelves on display.
In one exemplary embodiment, the lens types can alternate on the circuit board assembly 24 between the spotlight pattern 15 A configuration and the oval pattern 15 B configuration. This embodiment may aid in providing an evenly distributed vertical lighting area such as over product shelves. In particular, the lighting pattern is narrower near the housing such as near the top shelves and grows wider as it travels down to the lower areas such as near the bottom shelves. Additionally, the light from the oval pattern 15 B lenses overlaps to provide for more evenly lit areas.
The lenses 14 may be secured to the circuit board assembly 24 via a snap fit or by any other known suitable connection. As depicted in FIG. 5 , the lenses may be fixed individually, for example, one lens per one LED or one or more lenses may be connected together via connection 30 to create a uniform, one-piece lens assembly that is easier, faster, and more cost effective to install on the circuit board assembly.
The LED lighting housing can be adjustable in several ways to adjust the orientation of the housing and to fine tune the position of the projected light. First, the housing can be adjusted on horizontal arms (not shown) that are generally perpendicular to the long edge of the shelves and positioned above the top shelf in a set of shelves. This adjustment allows the LED lighting assembly to be moved closer to or farther from the plane being illuminated. The second adjustment allows the assembly to rotate about its horizontal axis 26 to direct light at a different angle in the plane. The two adjustments change the angle at which the light intercepts the product faces. Moving the lighting fixture away from the product on the horizontal arms can improve the lighting on the lower positioned product by reducing shadows on the product caused by the lower shelves.
Each of the LED lighting assemblies 10 modify the light output from the point source LED emitters 20 to illuminate an artificial planar surface area which can be represented by a front surface of product on a shelf in a retail store. Each LED lighting assembly can be approximately the length of a shelf in a retail store, typically 3 ft or 4 ft long. The LED lighting assemblies 10 can be positioned in a horizontal orientation above a product on the top shelf and slightly in front of an artificial plane. The light is modified by the plurality of lenses 14 fitted onto the circuit board 16 and over the LEDs 20 to capture the light from an LED, modify the beam pattern, and re-project the light evenly over a vertical plane in front of the product shelves.
The modified light projected onto the products on the retail shelf is relatively consistent in brightness over the planar surface and adds sufficient relative brightness beyond the general store luminaire lighting to call attention to or highlight the product merchandised on the shelf. Also, the lensing technique directs the available LED light such that the lighting pattern produced on the planar surface and the product faces is far more homogenous than that of a fluorescent system. Top, center, and lower product on the shelves is relatively evenly illuminated providing the desired effect for the consumer shopper. The modified light projected onto the products may increase shopper awareness of the products, better present the products, and increase the sales of products.
By capturing and directing a higher percentage of total light output from the LEDs using appropriate lensing, the illuminance per watt can be higher than is generally possible with a fluorescent light, adding to a further reduction in necessary power input to achieve the desired lighting effect and energy savings.
The LED circuit board and housing is designed to be thermally efficient and to remove as much heat from the LED as possible. Projected life of the LEDs is on the order of 4-6 times than that of typical existing fluorescent lamps. This reduces service call frequency by four to five times and commensurate cost.
Cost savings from reduced energy use and fewer service calls, along with improved sales from better product presentation may offset the cost of replacing existing fluorescent fixtures with an LED lighting fixture.
The reader should understand that these specific examples are set forth merely to illustrate examples of the invention, and they should not be construed as limiting the invention. Many variations in the lighting assemblies may be made from the specific structures described above without departing from this invention.
While the invention has been described in detail in terms of specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and methods. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. | Aspects of the disclosure relate to a lighting assembly and method for illuminating a vertical planar area, such as a merchandise display. The lighting assembly can comprise a circuit board having a plurality of LEDs arranged in a substantially straight line and an LED driver circuit, and an integral lens assembly. The integral lens assembly can have a plurality of lenses and each of the plurality of lenses can be placed over a corresponding one of the plurality of LEDs. The lenses capture the light from the respective LED, modify its beam pattern, and re-project the light such that the light emitted from the lighting assembly is distributed substantially evenly in a vertical plane or direction. | 5 |
CONTRACTUAL ORIGIN OF THE INVENTION
The United States Government has rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the U.S. Department of Energy and the University of Chicago representing Argonne National Laboratory.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for rapidly detecting the presence of duplex formation between single stranded nucleotide macromolecules, and more specifically, this invention relates to a method for using oligonucleotide arrays to rapidly detect duplex formation of oligonucleotide sequences. This invention also relates to a simple procedure for producing the oligonucleotide-arrays.
2. Background of the Invention
Present techniques for determining the existence of target sequences in patient DNA are complex, inefficient and somewhat time consuming. For example, one multi-step DNA sequencing approach, the Maxam and Gilbert method, involves first labeling DNA, and then splitting the DNA with a chemical, designed to alter a specific base, to produce a set of labeled fragments. The process is repeated by cleaving additional DNA with other chemicals specific for altering different bases, to produce additional sets of labeled fragments. The multiple fragment sets then must be run side-by-side in electrophoresis gels to determine base sequences.
Another sequencing method, the dideoxy procedure, based on Sanger, et al. Proc. Natl. Acad. Sci. USA 74, 5463-7 (1977) first requires the combination of a chain terminator as a limiting reagent, and then the use of polymerase to generate various length molecules, said molecules later to be compared on a gel. The accompanying lengthy electrophoresis procedures further detracts from the utility of this method as a fast and efficient sequencing tool.
A more recently developed sequencing strategy involves sequencing by hybridization on oligonucleotide microchips, or matrices, (SHOM) whereby DNA is hybridized with a complete set of oligonucleotides, which are first immobilized at fixed positions on a glass plate or polyacrylamide gel matrix. There are drawbacks to this technique, however. For instance, given that short nucleotide sequences are repeated rather frequently in long DNA molecules, the sequencing of lengthy genome strings is not feasible via SHOM. Also, hybridization with short oligonucleotides is affected by hairpin structures in DNA.
Furthermore, SHOM requires the utilization of high volume substrates containing many thousands of cells. If immobilized octamers are utilized to determine the positions of each of the four bases in genomic DNA, for example, then 4 8 or 65,536 such octamers, themselves which would need to be previously fabricated, would have to be immobilized in individual cells on the gel matrix.
The production of literally thousands of these cells on the polyacrylamide substrates is problematic. First, these cells must be accurately spaced relative to one another. Second, these cells must be of sufficient depth and volume to hold predetermined amounts of the oligonucleotide. Cell sizes can range from 25 microns (μm) to 1000 μm.
Typically, cells are produced in a myriad of ways. Two-dimensional scribing techniques and laser evaporation are two typical methods of cell formation. Mechanical scribing techniques are limited, however, in that the smallest structures which can be produced via this method are approximately 100 μm×100 μm. Lasers applications, because of their expense, also are limiting. Furthermore, both of these procedures require complex equipment and experienced personnel.
A need exists in the art to provide a rapid and efficient method for detecting the existence of complementary sequences to target DNA strands. This detection method should be performed using standard reagents found in a typical biochemistry facility. A need also exists for a method to produce accurate polyacrylamide matrices to be used in the above-disclosed duplex detection method. Such a matrix production method also must be simple enough to be performed in typically-equipped biochemical laboratories.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for rapidly detecting the formation and existence of duplexes between complementary nucleotide sequence strands that overcomes many of the disadvantages and reliability shortcomings of the prior art.
Another object of the present invention is to provide a method for the detection of DNA duplexes. A feature of the invention is the use of intercalating dyes. An advantage of the invention is the rapid detection of duplexes using typically-outfitted laboratories to perform standard procedures with common reagents.
Yet another object of the present invention is to provide a highly efficient method for detecting DNA duplexes. A feature of the invention is contacting a DNA duplex, contained on a high-volume support substrate, with an intercalating agent. An advantage of the invention is the enhanced ability to detect small amounts of formed DNA duplexes using standard, low-cost laboratory reagents.
Still another object of the present invention is to provide a method for producing a polyacrylamide matrix having thousands of individual and well defined holding cells. A feature of the invention is the use of mask-controlled photo-polymerization processes. An advantage of the invention is the rendering of high numbers of precise cell geometries and at high densities.
Briefly, the invention provides for a method for determining the existence of duplexes of oligonucleotide complementary molecules comprising constructing a plurality of different oligonucleotide molecules each of a specific length and each having a specific base sequence; supplying a matrix having a plurality of cells adapted to receive and immobilize the oligonucleotide molecules; immobilizing the different oligonucleotide molecules in the cells to fill the cells; contacting the now-filled cells with single stranded oligonucleotide molecules to form a duplex; contacting the duplex with an intercalating agent; and observing fluorescence levels emanating from the now-contacted duplex. A first fluorescence level is observed after the oligonucleotide molecules are immobilized to the matrix. The specific length of the different oligonucleotide molecules is selected from a range of between approximately 5 nucleotides and 30 nucleotides.
The invention also provides for a method for constructing oligonucleotide matrices comprising confining light sensitive fluid to a surface, exposing said light-sensitive fluid to a light pattern so as to cause the fluid exposed to the light to coalesce into discrete units and stick to the surface; and contacting each of the units with a set of different oligonucleotide molecules so as to allow the molecules to disperse into the units.
BRIEF DESCRIPTION OF THE DRAWING
The invention together with the above and other objects and advantages will be best understood from the following detailed description of the preferred embodiment of the invention shown in the accompanying drawing, wherein:
FIG. 1 is an elevated view of an polyacrylamide matrix assembly, in accordance with the present invention; and
FIG. 2 is a magnified view of the polyacrylamide matrix assembly illustrated in FIG. 1, in accordance with the present invention;
FIG. 3 is a plan view of a gel matrix, manufactured in accordance with the present invention;
FIGS. 4 A-B is a schematic view of an intercalating compound revealing a duplexed pair of oligonucleotide molecules juxtaposed to a polyacrylamide matrix, in accordance with the present invention; and
FIGS. 5 A-B is a plan view of a gel matrix disclosing the existence of duplexes when fluorescently labeled oligomer (I) is used, and when intercalating dye (II) is used to detect duplexes, in accordance with the present invention.
FIG. 6 is a plan view of a device for microdispensing aqueous solutions, in accordance with features of the invention;
FIG. 7 is an elevational, cross-sectional view of FIG. 6, taken along line 7--7;
FIG. 8 is an elevational, cross-sectional view of one of the microdispensing probes, in accordance with features of the invention;
FIGS. 9 A-D is a detailed view of harvesting of aqueous solutions, in accordance with features of the invention;
FIGS. 10 A-E is a detailed view of the deposition of aqueous solutions, in accordance with features of the invention; and
FIGS. 11 A-D is a detailed elevational view of a loaded gel element in progressive stages of development, in accordance with features of the invention.
DETAILED DESCRIPTION OF THE INVENTION
This invention involves incorporating intercalating techniques with processes for sequencing genetic material by hybridization methods (SBH) so as to produce a simple low resolution procedure for duplex formation analysis. This invention also teaches a method to produce polyacrylamide matrices having thousands of microscopic-sized, precisely configured and positioned holding cells designed to contain predetermined quantities of oligonucleotide mixtures.
The inventors have developed a method of using a mask-controlled photo-polymerization process to create micro-matrix topologies. The resulting micro-matrices are used to immobilize specific oligonucleotide strands designed to form duplexes with target DNA. The duplexes are contacted with an intercalating substance or dye to alert clinicians to the presence of duplexes.
Array Manufacturing Detail
The array manufacturing method, noted supra, incorporates a modified Methylene Blue induced photo-polymerization procedure whereby a polyacrylamide solution is prepared and then configured into desired shapes and sizes for subsequent polymerization.
The production of gel-matrices involves the construction of polymerization units into which prepared acrylamide fluids are placed. One exemplary polymerization unit is depicted in FIG. 1, as numeral 10, and partially magnified in FIG. 2.
In one embodiment of the invention, photo-polymerizations are performed on a solution containing 40 percent (between 30-45 percent, is suitable) acrylamide/Methylene Bis-Acrylamide (30:1) stock solution and 0.04 percent Methylene blue stock solution in water. The stock acrylamide solution is diluted with water to a concentration ranging from 4 to 8 percent and subsequently degassed with a water pump for 10 minutes. The gel matrix is prepared from a standard mixture of 0.5 μl 0.04 percent Methylene blue solution, 1 ml acrylamide solution and 10 μl N,N,N',N'-tetramethylethilendiamine (TEMED), from Aldrich (Milwaukee, Wis.).
The resulting, liquid (prepolymerized) mixture 12 is applied to a first surface of a quartz substrate 14, which is previously manipulated to contain a photomask. The preparation of the quartz substrate 14 involves applying a mask 20 to the first surface of the substrate 14, and then pretreating the first surface with an anti-wetting agent or an agent to increase the hydrophobicity of the surface. One such anti-wetting agent is a 2 percent solution of dimethyldichlorosilane in 1,1,1,-trichloroethane, having the trade name Repel-Silan™, and manufactured by Pharmacia Biotech of Uppsala, Sweden. Another suitable anti-wetting agent is trimethylchlorsilane. Two identical spacers 16, made from an inert material such as Teflon, of 20 μm thickness are placed on peripheral edges of the first surface of the quartz substrate so as form a pan-like container to confine the mixture 12. As such, a myriad of spacer thicknesses can be employed, depending on the final desired thickness of the polynucleotide chip.
A glass microscope slide 18, first pretreated with a material to attach polyacrylamide to glass, is placed on top of the spacers 16 to form a glass chamber 10. An exemplary pretreatment material is γ-Methacryloxy-propyl-trimethoxysilane, manufactured as Bind Silane by Pharmacia. This entire assembly or chamber 10 is fastened together via a myriad of fastening means (not shown), such as paper clips, tape, or inert adhesive.
A first surface of the quartz substrate 14 has a nontransparent mask (e.g., comprised of an inert opaque material such as chrome coating or permanent ink), containing a (grid) 20 defining a pattern of the desired topology. The grid 20 is applied to the mask coating surface of the quartz substrate 14 either by hand with a fine point marker or by photolithography, with the size of the gel elements defined by the dimensions of the transparent squares etched into the mask.
An exemplary grid is depicted in FIG. 3. Dimensions labeled as element "A" are the sizes of gel cells while elements "B" are illustrated as the spaces between the cells. The mask is designed to block the light, used in the light-induced acrylamide polymerization process, in the spaces "B" between the gel units 22 where gel coalescence is not desired.
Various sizes of gel cells were fabricated on separate masks, as disclosed in Table 1, below.
TABLE 1______________________________________Various Gel and Space Dimensions Obtained Via theInvented Process of Light-Induced Polyacrylamide Polymerization. Dimensions (μm)Mask # Gel Cells Interstitial Spaces______________________________________1 25 502 40 803 100 2004 500 1,0005 1,000 2,000______________________________________
After assembly, the assembled polymerization unit 10 is placed under a light source, such as a 312 nm UV-transilluminator such that the quartz substrate is closest to the source. Good results are obtained when the actual photomask layer 20, first deposited on the first surface of the quartz substrate 14, is in contact with the acrylamide solution. UV exposures of approximately 20 minutes provide good results. A myriad of wavelengths are suitable for the light-induced polymerization process, including those found in the range of between approximately 250 nm and 320 nm.
After exposure, the chamber 10 is disassembled. To facilitate disassembly, the chamber 10 can be placed in a water bath at room temperature. As noted supra, gel matrix units 22 are retained on the glass where light is allowed to permeate through the mask. These units 22 are separated from each other as a result of opaque mask portions, between the unit regions, precluding gel polymerization.
The resulting gel matrix is washed with water, placed in a solution for a period of time to introduce primary amino groups into the acrylamide (an exemplary solution being hydrazine hydrate). This period of time can range from 35-45 minutes. The matrix is then washed with water, and then treated to neutralize the remnants of the basic pH hydrazine treatment. One such neutralization procedure is placing the matrix in 1 percent acetic acid until neutralization is achieved, perhaps for 10 minutes. After neutralization, the matrix is washed with water, and then treated to remove any electrostatically sorbed chemicals. One such treatment involves placing the matrix in 1M NaCl for approximately 10 minutes. After a final washing with water, the unit is left to dry, and then treated with a thin film of an anti-wetting agent, such as Repel-Silan so as to make the interstitial glass spaces, designated as "B" in FIG. 3, hydrophobic. This will further isolate the gel units 22 from each other to minimize cross contamination during oligonucleotide loading. Treatment of the anti-wetting agent is brief, approximately 1 minute. The matrix is rendered ready for oligonucleotide loading after a final washing with ethanol (from 96 percent to neat) and then water to remove the ethanol.
Oligonucleotide Loading Detail
The inventors have developed a specific method for loading oligonucleotides onto matrices which are produced via the method outlined above. The method is fully disclosed in PCT/RU94/00179, filed on Aug. 11, 1993 to Mirzabekov. Described briefly, a pin is immersed into, and is wetted with, oligonucleotide solution. After being withdrawn from the solution, the pin is contacted with the gel surface.
During oligonucleotide aspiration, transfer and deposition, the temperature of the pin must be maintained near dew point at ambient temperature so as to prevent evaporation. Otherwise, the viscosity of the solution micro-volumes (typically 10 nanoliters or less) will lead either to complete evaporation or to incomplete transfer of the desired dose.
The invented transfer method allows for the transfer of a range of micro-volumes of oligonucleotide solutions, from 0.3 to 50 nanoliters (nl), with a dispensing error of no more than approximately ±20 percent. As disclosed in the above-identified PCT application PCT/RU94/00179, the device for microdispensing aqueous solutions of solutions is depicted in FIGS. 6-10. The device comprises a base 1 shaped as a rectangular plate, one side of which carries a plurality of rods 2 held with one of their ends to said plate. The rods 2 are arranged parallel to one another and spaced equidistantly to one another. Butt ends 3 of the rods are coplanar with one another and parallel to the base 1. A battery 4 of thermoelectric cells (e.g. Peltier elements) adjoins the base 1 on the side opposite to that equipped with the rods 2 and is in heat contact therewith. In this particular embodiment, the battery 4 is shaped similar in size to the base 1. The battery 4 is connected through wires, 5, to a controlled source 6 of direct-current. The battery 4 of thermoelectric cells is a means for maintaining the temperature of the butt ends 3 of the rods 2 equal essentially to the dew point of the ambient air. With its other side, the battery 4 of Peltier elements adjoins the surface of a flow-block radiator 7 and is in heat contact therewith. To provide a uniform heat contact between the surface of the battery and the base on one side, and between the radiator 7 on the other side, provision is made for thin (under 100 microns thick) layers 8 of a heat-conductive paste based on beryllium oxide and polydimethylsiloxane oil.
The base 1 and the rods 2 are made from a material having high thermal conductivity, preferably from a metal, such as copper or brass. The radiator 7 can be a silicon slab.
The rods 2 are provided with a heat-insulating coating 9 applied to half their length, including from the point of the rod attachment to the base plate 1. Material for the coating in this region can be polyolefin. One polyolefin product is Heat Shrinkable Pack, available through RS Components Ltd., England. The heat insulating coating 9 used to protect the surface of the base 1 exposed to atmospheric air can be formed polyurethane.
The rods 2 in the embodiment illustrated are round in cross-section (though they may have any other cross-sectional shape) and their vacant ends are shaped as cone frustums tapering to the ends. A hydrophilic coating 30 such as glass or gold, is applied to the butt ends 3 of the rods 2, whereas a hydrophobic coating 11 such as fluoroplastic, or glass whose surface is hydrophobized by treatment with Repel Silane, is applied to the side surfaces of the vacant ends of the rods.
The area of the butt ends 3 of the rods is selected such as to obtain the required volume V of the dose being transferred and to obey the following relationship: V≈1/3πR 3 ·10 -6 nanoliters, where V is the required volume of the droplet forming on the butt rod end after the rod has been withdrawn from the solution, and R in microns is the radius of the butt rod end.
The device as described above is used as follows to facilitate liquid transfer: The base 1 carrying the rods 2 are positioned opposite to the tray 32 in such a manner that each rod is located against a respective well 13 of the tray 32 filled with an aqueous solution 34 of the substance to be transferred, e.g., an aqueous oligonucleotide solution. Then the base 1 is displaced towards the tray 12 until the ends of the rods 2 (FIG. 9 b) contact the solution 34. Then, by displacing the base 1 together with the rods 2, (FIG. 9 c) in the opposite direction, the rods 2 are withdrawn from the solutions, with the result that a microdose 15 (FIG. 9 d) of the solution of the substance is formed on the butt end of each rod 2. The volume V of the microdose is independent of the depth of immersion of the rod 2 into the solution 34 (due to the hydrophilic butt end of the rod and hydrophobic coating on the rod's side surface with respect to the solution being transferred) and is determined substantially by the radius R alone of the butt end of the rod 2.
Next, the base, together with the rods loaded with the microdoses of the solution, is transferred to the gel elements 22 arranged in a micromatrix of the type depicted in FIG. 3. The layout of the gel elements 22 complement the configuration of the oligonucleotide-loaded rods so that when the base 1 is positioned opposite to the surface of the matrix, each rod 2 is opposing a respective gel element 22. Thereupon, the base 1 is displaced towards the matrix 18 along the arrow as depicted in FIG. 10 b, until the microdoses 15 contact the gel areas 22. During transfer, the temperature of the solution 34 and the butt ends 3 are maintained at the dew point of the air to minimize evaporation of the solution during the transfer. Control of the temperature of the butt ends 3 are attained by changing the battery 4 voltage of the thermoelectric cells in response to the signal produced by a temperature transmitter (not shown) in heat contact with the base.
Upon contact with the microdose 15, the gel element 22 vigorously absorbs the solution (FIG. 10 c), with the result that the gel areas 22 swell and the microdoses are drawn into the gel.
After fluid transfer, the base 1 supporting the rods 2 is retracted from the micromatrix. The rods then are washed and dried for reuse.
Oligonucleotide Immobilization Detail
The inventors have developed an immobilization procedure for coupling micromolecules to acrylamide gels so as to minimize liquid evaporation during immobilization and to also ensure that covalent bonding of oligonucleotides to the gel matrix units proceeds to completion. This procedure is more fully disclosed in PCT/RU94/00178, filed on Aug. 11, 1993, to Yershov.
Briefly, the immobilization process is as follows: Micro-volumes of bioorganic solutions are loaded onto the micro-matrix cells, with the temperature of the micro-matrix being maintained equal to that of the ambient air. Once the micro-volumes of the oligonucleotide solutions have been applied to the cells of the matrix, the micro-matrix temperature is set equal to or below the dew point of the ambient air. This temperature is maintained until swelling of the gel is complete and noncoalescent droplets of water condensate appear in the spacings "B" between the cells.
After the appearance of the water condensate, a thin layer of an inert, nonluminescent oil is applied to the micro-matrix surface so as to prevent oligonucleotide evaporation. An oil layer of at least approximately 100 μm provides good results. A myriad of inert oils are suitable including, but not limited to, purified Vaseline®, phenyl (10 percent) methylsilicone oil, phenyl (20 percent) methylsilicone oil, among others.
The micro-matrix is kept under the oil layer until completion of the oligonucleotide immobilization process, and preferably for 48 hours. The oil is then removed by washing with a polar substance that will not cause oligo denaturing, such as ethanol, or water. The matrix is dried and stored indefinitely, ready for use.
As disclosed in the above identified PCT application PCT/RU94/00178, the process is illustrated in FIG. 11, wherein a fragment of the micromatrix 18 is shown in a sectional side-elevational view. FIG. 11 a depicts the immobilization sequence at the instant when microvolumes of bioorganic solutions 15 are being loaded to the gel elements 22. At this point, the temperature of the micromatrix 18 is maintained equal to that of the ambient air.
As is depicted in FIG. 11 b, at the completion of loading, all residual droplets of the bioorganic solution 15 evaporate, and the condition of the gel is the same in all cells.
At the instant when the water condensation from the ambient air has been completed, the temperature of the micromatrix 18 is below or equal to the dew point of the ambient air. The gel cells 22 have swollen and are coated with water condensate 36. Minute droplets of condensate also appear in the intercell spacings. As depicted in FIG. 11 c, the droplets do not coalesce with one another.
FIG. 11 d depicts the entire assembly coated with the film 38 of the nonluminescent oil, with a thickness of over 100 microns. The temperature of the micromatrix is equal to that of the ambient air.
This aforementioned process is applicable for immobilizing any water-soluble bioorganic substances to the carrier, especially in cases which require the presence and retention of the liquid (aqueous) phase to facilitate completion of covalent bonding in the system substance-carrier.
An exemplary embodiment of the duplex detection method, incorporating the produced micro-matrix topologies, is schematically depicted in FIGS. 4A-B as numeral 200. FIG. 4A depicts an oligomer, 212, immobilized to a gel matrix unit 214. The oligomer is constructed to contain an intercalating tag, 216 such as ethidium bromide. Other intercalating agents, such as propidium iodide, also can be employed.
In the free state, depicted in FIG. 4A, wherein the intercalating agent is not juxtaposed between base planes of a duplex, the tag fluoresces at a certain intensity. Part of this fluorescence is due to higher background and lower-signal-to-background noise that results from intercalating dyes reacting with single-stranded oligonucleotides. However, fluorescence is magnified far above background levels when duplexes do occur. As can be noted in FIG. 4B, when a single strand 218 of a target oligonucleotide molecule, complementary to the immobilized oligomer, is contacted with the loaded gel unit, duplexing occurs. The inventors observed that the intercalating agent, now juxtaposed between the base planes of the duplex, fluoresces at an intensity that is approximately 10 times that observed in the free state. This higher intensity is observed within approximately one minute.
As an alternative to first binding the intercalating agent to the immobilized oligomer, the intercalating agent can instead be bound to the target single strand oligonucleotide molecule 218. In yet another alternative, addition of the intercalating agent can be made after duplexing occurs between the immobilized oligo fraction 212 and the mobilized single strand target sequence 218.
For example, fluorescence enhancements are achieved when intercalating dyes such as thiazole orange homodimer (TOTO) or oxazole yellow homodimer (YOYO) are used, both of which are manufactured by Molecular Probes, Eugene Oreg. DNA binding fluorochromes specific for double-stranded DNA also provide good results.
Use of AT-specific fluorescent ligands that stabilize these pairs also enhance the fluorescent process by equalizing AT stability vis-a-vis GC-rich interactions.
EXAMPLE
FIG. 5 illustrates the efficiency of using either fluorescently labeled target ss DNA strings (a) or intercalating dyes (b) to rapidly detect duplex formation. This plan view depicts the same matrix of polyacrylamide cells, whereby the matrix is manufactured by the methods disclosed supra. The matrix is comprised of 16 cells, each cell loaded with the octamer CyAACCxT-5'. As shown, the 3' end is anchored to the gel and not available for further interaction. The immobilized octamer varies at two base positions "y" and "x" as shown along the boundaries of the matrix.
As can be determined in FIG. 5 (A), when the octamer-loaded matrix is hybridized with fluorescently labeled ss DNA, such as the 19-mer CCTGGGCAGGTTGGTATCA, a clear signal is seen when a perfect GC and TA match is made at duplexing. The fluorescent label used in this instance was HEX, available through Applied Biosystems, Foster City, Calif. Another suitable dye is tetramethylrodamine.
In a separate experiment, when the octamer-loaded matrix is hybridized with the unlabeled 19-mer in the presence of an intercalating agent, a clear signal again is seen at the GC and TA matching cell location. This can be noted in FIG. 5 b. Weaker signals also are detected, however. For example, signals were observed when just TA or GC interaction was observed. This indicates that when background noise is controlled, the use of an intercalating agent or a plurality of intercalating agents may be more sensitive than the use of fluorescent dyes for detecting at least partial matches when rapid determinations are desired. The intercalating agent used in this instance, ethidium bromide, was added after the duplexing between oligomer strings occurred.
However, and as discussed supra, intercalating agents also can be first attached to either the shorter oligomer strand prior to immobilization or to the target single strand prior to hybridization.
While the invention has been described with reference to details of the illustrated embodiment, these details are not intended to limit the scope of the invention as defined in the appended claims. | A method for determining the existence of duplexes of oligonucleotide complementary molecules is provided whereby a plurality of immobilized oligonucleotide molecules, each of a specific length and each having a specific base sequence, is contacted with complementary, single stranded oligonucleotide molecules to form a duplex so as to facilitate intercalation of a fluorescent dye between the base planes of the duplex. The invention also provides for a method for constructing oligonucleotide matrices comprising confining light sensitive fluid to a surface, exposing said light-sensitive fluid to a light pattern so as to cause the fluid exposed to the light to coalesce into discrete units and adhere to the surface; and contacting each of the units with a set of different oligonucleotide molecules so as to allow the molecules to disperse into the units. | 1 |
This is a continuation of copending application Ser. No. 07/735,161 filed on Jul. 23, 1991 now abandoned which is a continuation of application Ser. No. 07/617,959, filed on Nov. 26, 1990 now abandoned, which is a continuation of application Ser. No. 07/443,875 filed on Nov. 30, 1989, now abandoned, which is a continuation of application Ser. No. 06/599,005, filed Apr. 11, 1984, now abandoned.
BACKGROUND OF THE INVENTION
Certain injuries to the eye and certain diseases to the eye (e.g. cataracts) require surgical removal of the eye lens. Removal of the natural lenses of the eye is known as aphakia which must be corrected by the use of a corrective lens in order to restore vision. Generally, intraocular implants are used to correct aphakia and restore vision. These implants may be permanently placed in the anterior or posterior chamber of the eye. Intraocular implants have an optical lens and a haptic for fixation of the lens, by a surgeon, in the anterior or posterior chamber of the eye. However, even with the most suitable of lenses, vision is not as desirable as it should be for the aphakic individual since such lenses do not adequately compensate for certain changes in light transmission which occur in the absence of the natural human crystalline lens. The result is potential damage to the retina due to increased ultraviolet light transmission.
A considerable portion of incident light entering the eye is absorbed and only the unabsorbed or transmitted portion strikes the retina. Natural light encompasses the entire spectrum of wavelengths in the ultraviolet, visible and infrared radiation ranges. Various artificial light sources also contain many wavelengths.
The crystalline lens of the eye preferentially absorbs a substantial portion of ultraviolet radiation. Accordingly, it is desirable that the lenses of intraocular implants for aphakic individuals, absorb at least 90% of light in the 300 to about 380 nm range but transmit most of the light in the visible spectrum. In addition, intraocular implant lenses are preferably made of a thermoplastic polymer and optically clear, inert to the eye, biocompatible and have a specific gravity of less than about 1.7.
Polymethylmethacrylate sometimes referred to as "PMMA", and various copolymers thereof, have the desired properties discussed above and have been used to make intraocular lenses as well as haptics. PMMA has physical properties which permit it to be formed into introcular optic lenses that are relatively thin in cross section and, because of PMMA's relatively low specific gravity, about 1.4 or lower, such lenses are relatively comfortable in the eye. However, PMMA, and copolymers thereof have a serious disadvantage in that they are substantially transparent to ultraviolet radiation which, if transmitted to the retina, can cause eye injury. To avoid this disadvantage intraocular lenses have been fabricated from glass which can absorb ultraviolet radiation. However, compared to PMMA which is relatively easy to machine, glass lenses of relatively thin cross sections are much more difficult to produce. Furthermore since glass lenses have a specific gravity of 2.5 or higher such lenses are relatively heavy and therefore mitigate against the use of such lenses in aphakic individuals.
To overcome the disadvantage of PMMA lenses to ultraviolet radiation transmission, natural and synthetic crystals have also been used to construct intraocular lenses. U.S. Pat. No. 4,079,470 discloses a chemically durable optical implant lens formed from a low density natural or synthetic crystal, such as Corundium, Sapphire, Ruby, Sircon, Strontium, Diamond or Anatase. Because of the ability of these materials to absorb ultraviolet radiation such crystals provide an advantage over lenses made from PMMA. However, as with glass, it is more difficult to produce intraocular lenses which have relatively thin cross sections from these crystals. In general, lenses made from such crystals must be considerably thicker than lenses made from PMMA. Crystal lenses like glass lenses, are relatively heavy due to their high specific gravity, about 3.5 or higher, and larger size. Consequently, such crystal lenses are also heavier than the natural lenses of the human eye, and may also impose an undesirable strain to the eye. For these and other reasons, intraocular lenses made from PMMA, tend to be preferred over synthetic or natural crystals and glass lenses.
There is a need for an intraocular implant having an optical lens which is nontoxic, biocompatible and which absorbs a high percentage of ultraviolet light and does not contain leachable or potentially harmful ultraviolet light absorbing additives.
There is also a need for an intraocular optical lens material made of a thermoplastic polymer which is strong, ductile and easily machined or molded into thin sections and having a specific gravity less than about 1.7 and preferably about 1.4 or lower, which is chemically inert and stable, is biocompatible, nonleachable by fluids of the eye, is optically clear and absorbs a major portion of harmful ultraviolet light.
SUMMARY OF THE INVENTION
In accordance with the present invention, novel intraocular implants are provided which have optical lenses that are light, non-toxic, biocompatible, nonleachable in the presence of eye fluids and absorb at least 90% of the ultraviolet light in the 300-380 nm wavelength range but are transparent to most of the visible radiation. The intraocular implants will have a haptic for fixation in the posterior or anterior chamber of the eye.
The haptics of the intraocular implant may have a variety of shapes and can be made of a variety of thermoplastic polymers which are biocompatible, chemically inert, light weight (i.e. have a specific gravity of less than 1.7) strong, tough and flexible and are inert to the fluids in the eye. Such haptics may be made of polypropylene, aromatic polycarbonates, aromatic polyesters, aromatic polyimides, aromatic polyethersulfones, etc.
The intraocular lens of the present invention will have optically finished front and back surfaces and a shape and size approximating the human lens and will be made of an optical quality thermoplastic polymer having a specific gravity of less than about 1.7, said thermoplastic polymer having uniformly distributed throughout an ultraviolet light absorbing effective amount in the 300-380 nm range of 2-(hydroxy, lower alkylphenyl) benzotriazole which, optionally, may be halogen (e.g. chlorine) substituted in one or more of the 4, 5, 6 or 7 positions.
The intraocular lenses are formulated so that the ultraviolet radiation absorbing substance is nonleachable in the eye from said thermoplastic polymer. The ultraviolet absorbing substance is also substantially nontoxic. The amount of ultraviolet radiation absorbing substance is small enough so the lens is transparent to most of visible radiation but great enough to render the lens absorbent to at least 90% of the ultraviolet radiation of sunlight in the 300 to 380 nm range.
The critical requirement of the invention is that the ultraviolet radiation absorber be effective at low concentrations and be nonleachable or nonextractable from the solid thermoplastic polymer in the eye.
The solid thermoplastic polymer may be polymethylethacrylate, and copolymers thereof with monomers such as methylacrylate, hydroxyethylmethacrylate, ethyl acrylate, butyl acrylate, mixtures thereof, and the like. The particular monomer, or combination of monomers, as well as other additives, such as cross-linking agents and polymerization catalysts, used to form the various polymeric systems are known in the art. Other thermoplastic polymers well suited to be used in both the lens and haptic include aromatic polycarbonates such as lexan available from General Electric; polysulfones such as Udel P-1700 available from Union Carbide; and polyetherimides such as Ultem available from General Electric.
The ultraviolet light absorbing compounds useful in the present invention are stable, inert, biocompatible, water insoluble, non-leachable and strongly ultraviolet
5 light absorbing compounds based on the benzotriazole structure and include 2-(3',5'-ditertiary butyl-2'-hydroxy phenyl) benzotriazole, 2-(3'-tertiary-butyl-5'-methyl-2'-hydroxy phenyl-5-chlorobenzotriazole and 2-(2'-hydroxy-5'methylphenyl)benzotriazole.
In the formulation and production of the lenses of this invention, the amount of the ultraviolet radiation absorber will be sufficient to absorb at least 90% of the ultraviolet radiation of sunlight in the 300-380 nm range but will not prevent the lens from being transparent to a substantial part of the visible spectrum.
The lenses of this invention may be easily produced using standard procedures such as lathe cutting, injection molding, compression molding and casting.
The ultraviolet light absorbing compound may be uniformly distributed through the thermoplastic polymer by the polymerization of the monomers in the presence of the ultraviolet radiation absorbing compound. Alternatively, the ultraviolet light absorbing compound may be compounded with the thermoplastic polymer prior to extrusion or molding. The amount of the absorbing compound is preferably from about 0.01 to about 5 parts by weight per 100 parts by weight of the polymer. The ultraviolet light-absorbing compounds of this invention are inert and do not adversely affect the polymerization of the monomers used to produce the thermoplastic polymers, or their processing by molding or extrusion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration in plan view of an intraocular implant for implantation in the anterior chamber of the eye.
FIG. 2 is a side view of the intraocular implant of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The intraocular implant of the present invention will have a generally circular optic lens 10 as shown in FIGS. 1 and 2 which is made of a thermoplastic polymer having uniformly distributed therethrough an ultraviolet light absorbing amount of 2-(hydroxy-lower alkylphenyl) benzotriazole which may be halogen substituted in the 4, 5, 6 or 7 positions. The amount of benzotriazole distributed throughout the polymer is preferably from about 0.01 to about 5 parts by weight of the thermoplastic polymer.
The ultraviolet light absorbing substance may be mixed with the monomers and then the monomers polymerized or by compounding with the thermoplastic polymer prior to extrusion or molding.
In addition to the optic lens 10, the intraocular implant of the present invention also have haptics connected to the optic lens for positioning and fixing the implant in either the anterior or posterior chamber of the eye. In the embodiment of this invention shown in FIGS. 1 and 2, haptic 11 and haptic 12 are resilient so that they can be compressed when being placed in the eye but will spring out when the implant is in the correct position so that positioning element 13 of haptic 11 and positioning element 14 of haptic 12 will contact and be seated in the groove of the anterior chamber of the eye. Aperture 15 and aperture 16 are provided for grasping with forceps.
The haptics may be made of any thermoplastic polymer which is strong and lightweight, chemically inert and biocompatible. The haptic may be made of the same material as the lens, e.g. polysulfone, polycarbonate, etc., or may be different, e.g. a PMMA optic with polypropylene haptic.
TEST RESULTS
Example 1
Three fine dispersions of 200 micro-grams of each of the following ultraviolet light absorbing compounds in a 0.9% saline solution were made: 2-(3',5'-ditertiarybutyl-2'-hydroxy phenyl) benzotriazole (hereinafter DHP), 2-(2'-hydroxy-5'-methylphenyl) benzotriazole (hereinafter HMP), and 2-(3'-tertiary-butyl-5'-methyl-2'-hydroxy phenyl-5-chlorobenzo-triazole (hereinafter TMP). Each of the three saline solutions were injected, respectively, into the anterior chamber of the eyes of three rabbits. This amount is the equivalent of 1 weight % of ultraviolet light absorbing compound in a 20 mg. lens.
No adverse reactions were noted. The animals were followed for one week and the eyes were normal and tissue histology was normal. This test demonstrates the non-toxic biocompatible properties of the ultraviolet light absorbing compounds.
Example 2
100 parts by weight of polysulfone (Udel P-1700) pellets were mixed with 8 parts by weight of TMP powder. The mixture was extruded into a rod at 550° F. to 600° F. and then cut into discs of about 1.0 mm thickness. The discs absorbed over 95% of the ultraviolet light in the 300 to 400 nm region and had a sharp cut-off of absorption between 400 and 420 nm.
Example 3
100 parts by weight of polysulfone (Udel P-1700) pellets were mixed with 10 parts by weight of DHP powder. This mixture was compression molded into a 1 mm thick sheet which absorbed over 95% of the ultraviolet light in about the 300 to 400 nm region and had a sharp cut-off of absorption in the 400 to 420 nm region (there was 5% transmission at 403 nm and 70% at 420 nm).
Example 4
A sheet, 2.95 mm thick, was made having 100 parts by weight of PMMA and 10 parts by weight of DHP. The sheet absorbed more than 95% of ultraviolet light in the 300-400 nm region and had a sharp cut-off of absorption in about the 405 to 430 nm range (there was less than 5% trans mission at 405 nm and about 90% transmission at 430 nm).
Example 5
A sheet, 1/8 inch thick, was made having 100 parts by weight of PMMA and 10 parts by weight of HMP. This sheet absorbed over 95% of the ultraviolet light between 300 and 400 nm with a sharp cut-off of absorption at about 400 nm (there was about 5% transmission at 400 and over 90% transmission at about 425 nm).
Example 6
The PMMA containing HMP material used in Example 5 was used in this example. Four samples of the material were extracted in four (4) different media for one (1) hour at 121° C.
1. Sodium chloride
2. Ethanol in sodium chloride
3. Polyethylene glycol
4. Cottonseed oil
Two rabbits were used for each extract. Exactly 0.2 ml of test material extract was injected intracutaneously in ten (10) sites on the right side of each animal and ten (10) injections of 0.2 ml of extracting medium were placed into the left side of each animal. The degree of erythema and edema of the two sides were compared 1, 2 and 3 days after the injection to determine the degree of tissue reaction.
There were no significant signs of erythema nor edema due to the intracutaneous injection of extraction of the PMMA material as compared to injections of the extraction mediums. Therefore, an extract of PMMA material does not result in erythema or edema 72 hours after intracutaneous injection. This test demonstrates the non-toxic and nonleachable properties of the ultraviolet light absorbing additive.
Example 7
Four (4) grams of material having the same composition as used in Example 6 were cut into 11 pieces approximately 1.016 cm square and 0.3 cm thick (37.07 cm 2 total surface area for each 4 grams). The materials were cleaned and sterilized. The 4 grams were then incubated at 90° C. in 20 ml of saline (1 gr for each 5 ml of saline or 1 cm 2 surface area for each 0.55 ml of saline). After 1.5 weeks of 90° C., the material was removed and the ultraviolet absorbace of the extract measured. The concentration of the absorber in the extract was determined from the absorbance.
The absorbance of pure saline subtracted from the absorbance of the extract of the ultraviolet absorbing PMMA, was always less than 0.004 between wavelengths of 300 and 400 nm. Since the ultraviolet absorber strongly absorbs ultraviolet radiation and is stable above 140° C., it would have been detected by this method. Therefore, there was no significant leaching of ultraviolet absorber, since there was negligible absorbance of the ultraviolet filtering PMMA extract.
Example 8
Intraocular implants of PMMA containing 0.1 weight percent of HMP were implanted in the anterior chamber of rabbits. No toxic or adverse behavior was observed after one year. There was also one explanted lens which showed no change in ultraviolet light absorbing properties. | Intraocular implants having optical lenses that are light, non-toxic, biocompatible, nonleachable in the presence of eye fluids and absorb at least 90% of the ultraviolet light in the 300-380 nm wavelength range but are transparent to most of the visible radiation. The intraocular implants will have a haptic for fixation in the posterior or anterior chamber of the eye. The optical lens has uniformly dispersed therein an ultraviolet light absorbing amount of 2-(hydroxy-lower alkylphenyl) benzotriazole which may be halogen substituted in the 4, 5, 6 or 7 positions. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to related U.S. Pat. No. 6,238,459 to William Downs (also a named co-inventor in the present application), issued May 29, 2001. U.S. Pat. No. 6,238,459 is hereby incorporated by reference as though fully set forth herein. Unless otherwise stated, definitions of terms in that patent are also valid for this disclosure.
[0002] This Continuation Application bases its priority from co-pending U.S. Ser. No. 09/284,973, filed on Apr. 23, 1999 and titled “Gasification Process for Spent Liquor at High Temperature and High Pressure.” To the extent that the parent application previously incorporated by reference now-abandoned U.S. Ser. No. 09/284,533 filed by Jerry D. Blue, William Downs, Timothy A. Fuller, and Christopher L. Verrill on Apr. 23, 1999, and titled “Sulfur Recovery From Spent Liquor Gasification Process,” the text of the U.S. Ser. No. 09/284,533 application is now explicitly included the text of this Continuation Application.
FIELD AND BACKGROUND OF THE INVENTION
[0003] The present invention relates in general to pulp and paper spent chemical recovery processes, and in particular to a new and useful spent liquor gasification process, such as a black liquor gasification process, which provides a more efficient utilization of the spent chemical's fuel value in the production of electric power and which allows for the recovery of sulfur and other useful products from such spent liquor.
[0004] There is a large body of prior art relating to the removal and/or recovery of H 2 S from petroleum and natural gas processes and from pulp and paper spent liquor chemical recovery processes. The motivation for removing H 2 S from petroleum and natural gas processes is singularly to improve the quality of the product. Usually, these processes convert the H 2 S to solid elemental sulfur because it facilitates storage and transportation. Most sulfur thus produced is ultimately converted to sulfuric acid at the point of use. In a few instances, H 2 S is converted to sulfuric acid directly.
[0005] Prior art for H 2 S recovery in the pulp and paper industry varies according to the specifics of the process. U.S. Pat. No. 3,323,858 deals with the absorption of H 2 S with carbonate liquor. The carbonate liquor is then causticized to caustic liquor. U.S. Pat. No. 4,297,330 uses hot potassium carbonate to produce an acid gas stream containing H 2 S, CO 2 and H 2 O. The selectivity of that process for H 2 S recovery over CO 2 recovery is only about 12 to 1. By comparison, as set forth in the DESCRIPTION OF THE PREFERRED EMBODIMENTS of the present invention, the selectivity of H 2 S recovery over CO 2 recovery according to the present invention must be typically better than 100 to 1. Furthermore, the process described in U.S. Pat. No. 4,297,330 is not capable of achieving that degree of selectivity.
[0006] U.S. Pat. No. 4,609,388 describes a process that separates all of the components of a fuel gas into separate pure component streams. This process requires the complete dehydration of the fuel gas. This fact alone makes this process inappropriate for a spent liquor gasification process.
[0007] U.S. Pat. No. 5,205,908 deals directly with the issue of absorbing H 2 S from a fuel gas generated by gasification of spent liquor. It is quite specific in stating that the absorption of H 2 S is done with an alkaline wash solution that is not green liquor and has a composition where the mole ratio OH − /HS − is greater than 8. This patent does not deal at all with the issue of the co-absorption of CO 2 and therefore is missing primary elements for its practical application.
[0008] U.S. Pat. No. 5,556,605 uses carbonate liquor to absorb both H 2 S and CO 2 followed by steam stripping out the H 2 S and using it outside the kraft pulping process in a process such as the Neutral Sulfite Semi-Chemical (NSSC) pulping process.
[0009] U.S. Pat. No. 5,660,685 deals with spent liquor gasification in such a way that H 2 S is removed from the fuel gas and then returned to the gasifier so that the carbonate liquor produced by dissolving the molten salts from the gasifier has a very high sulfidity, and little carbonate. In the extreme, this approach has the possible advantage of eliminating the causticizing step. Although this idea has certain appeal, it has some significantly difficult steps; e.g., a Claus Reactor, H 2 S compression and re-injection, and would be very difficult to implement.
[0010] A schematic representation of a conventional kraft recovery process is depicted in FIG. 1. This process consists of several unit operations. The key ones are the combustion of black liquor in a process recovery boiler 10 , the conversion of green liquor to white liquor in a slaker/causticizer 12 , the production of steam 14 for both process use and electric power production, and the calcination of calcium carbonate to lime (calcium oxide) in a lime kiln 16 .
[0011] Gases from the recovery boiler 10 are passed to a dust collection apparatus 18 , such as an electrostatic precipitator (ESP), and yield flue gas at 20 which can be released to a stack (not shown). Salt cake is returned at 22 to the inlet of recovery boiler 10 where it is mixed with incoming black liquor and combusted with air. Smelt at 24 from boiler 10 is passed to a dissolving tank 26 where it is contacted with weak wash 28 . Dissolving tank 26 discharges green liquor 30 for input into the slaker/causticizer 12 . White liquor 32 from the slaker/causticizer 12 is supplied to a digester (not shown) while reburned lime at 34 from kiln 16 is provided into the slaker/causticizer 12 where it reacts with sodium carbonate to produce the white liquor and solid calcium carbonate 36 . The white liquor and solid calcium carbonate 36 are separated on a filter, 38 , into a filter cake called lime mud 40 and the filtrate, i.e. the white liquor. The lime mud is washed with water, and the filtrate from the washing step is called weak wash 28 . The lime mud 40 is provided to the kiln 16 which discharges flue gas 42 to a kiln stack (not shown).
[0012] This is a very mature process with few improvements over the past 40 years.
[0013] Although no fill scale, high pressure, high temperature, oxygen blown black liquor gasification (BLG) processes have been built to date, process concepts have been published. A generic process is depicted in FIG. 2. FIG. 2 illustrates one of the principal advantages of black liquor gasification over the conventional kraft recovery process, i.e., a substantial improvement in cycle efficiency through the use of combined cycle technology in the form of a gas turbine/steam turbine couple 50 . In FIG. 2 and the remaining figures, the same reference numerals will be used to designate the same, or functionally similar parts.
[0014] One of the consequences of BLG is that a substantial portion of the sulfur in the black liquor is partitioned to the gas phase when compared to the conventional kraft process. In an H 2 S scrubber 58 of the system depicted in FIG. 2, sulfur in the form of H 2 S is reabsorbed into a mixture 52 of weak wash 28 and white liquor 56 . CO 2 will also absorb into this solution. In fact, most of the free hydroxide in the mixture 52 of weak wash 28 and white liquor 56 will be consumed by the CO 2 . It is therefore necessary to recycle an effluent 54 from the H 2 S scrubber 58 back through the causticizing plant 12 (via the quencher 26 ) as shown in FIG. 2. This has the undesirable effect of increasing the burden on the causticizing plant 12 and lime kiln 16 by as much as 50% and results in a very large thermal penalty to the black liquor gasification process.
[0015] The black liquor gasification process can also generate a significant quantity of sub-micron sized alkali fume and soot. Alkali fume is extremely damaging to gas turbine blades. For this reason, it is vitally important that alkali fume and soot be controlled to a significant extent, perhaps to a removal efficiency as high as 99.9997% (five nines control). The conventional BLG process purports to do adequate control of fine particulate in a single venturi scrubber 60 . However, the energy required to achieve adequate fume control in the single venturi scrubber 60 again places a significant energy penalty on the BLG process.
SUMMARY OF THE INVENTION
[0016] The approach of the present invention to H 2 S recovery and reuse differs significantly from the prior art.
[0017] An object of the present invention is to provide a method and apparatus for processing a waste stream from digestion of lignocellulosic material to form useful products, comprising: partially oxidizing the waste stream to form hot gases and molten salts; cooling the hot gases and molten salts using a quench liquor to form quenched gas and carbonate liquor; removing particles from the quenched gas to form a raw fuel gas; removing H 2 S from the raw fuel gas using an H 2 S removal process which is more selective for H 2 S than it is for CO 2 , the removing step forming usable fuel gas as one useful product, and acid gases; and
[0018] further processing the acid gases to form additional useful products.
[0019] Another object of the present invention is to provide a method and apparatus for producing clean, sweet, fuel gas for use in a combustion process by processing a waste stream from digestion of lignocellulosic material. This aspect of the invention requires removing particles from the quenched gas to form a raw fuel gas by subjecting the quenched gas to a multi-step fume reduction process which includes heat extraction from the quenched gas to reduce particulate load and water content of the quenched gas to form a low fume fuel gas. H 2 S is removed from the low fume fuel gas using an H 2 S removal process which is more selective for H 2 S than it is for CO 2 , the removing step forming clean, sweet, fuel gas and acid gases. Finally, the clean, sweet, fuel gas is conveyed to a combustion process.
[0020] The various features of novelty which characterize either embodiment of the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In the drawings:
[0022] [0022]FIG. 1 is a flow chart showing a prior art kraft recovery apparatus and method;
[0023] [0023]FIG. 2 is a flow chart showing a prior art black liquor gasification apparatus and method;
[0024] [0024]FIG. 3 is a flow chart showing the apparatus and method of the present invention;
[0025] [0025]FIG. 4 is a graph plotting carbonate content against the hydrogen sulfide-carbon dioxide ratio;
[0026] [0026]FIG. 5 is a flow chart showing a typical proprietary SELEXOL process used in accordance with the present invention;
[0027] [0027]FIG. 6 is a flow chart similar to FIG. 1, but showing a conventional process; and
[0028] [0028]FIG. 7 is a flow chart showing an alternative embodiment employing a plurality of absorption-stripping units connected in series;
[0029] [0029]FIG. 8 is a flow chart showing the apparatus and method of the present invention; and
[0030] [0030]FIG. 9 is a schematic diagram of a fume and soot collection system of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] It should be initially noted that, while the method and apparatus of the present invention will likely find first commercial application to the processing of black liquor produced in the well known kraft pulping and recovery process, the present invention is not limited to that particular type of pulping process. For example, the present invention can also be applied to process alkaline, acidic, or neutral sulfite spent liquors, as well as polysulfide spent liquors. As is known to those skilled in the art, the terms “black liquor” or “smelt” are commonly used in connection with the kraft pulping process, while sulfite spent liquors are commonly called “red” liquors and not “black”, and polysulfite pulping liquor is commonly called “orange” liquor and not “white” liquor. Accordingly, it will be understood that while the terms black liquor, smelt, green liquor, white liquor, lime mud, and weak wash have been employed in the Figures and in the following description of the preferred embodiment of the invention, persons skilled in the art will appreciate that the invention is not limited merely to the kraft pulping process. Corresponding broader terminology such as spent liquor, molten salts, carbonate liquor, caustic liquor, and calcium carbonate solids may be substituted, respectively, for those terms as applicable, together with the same term weak wash depending upon the particular type of pulping process that is involved. Such broader terminology has been employed in the claims appended to and forming a part of this specification. Similarly, the present invention employs the term “lignocellulosic” to encompass all of the various types of feed stocks which one might want to employ in a pulping process, to broadly include woody and non-woody plants, whether or not the kraft type pulping process or other types of pulping processes are employed. For further details of the various aspects of pulping processes used in the paper industry, the reader is referred to STEAM Its Generation and Use, 40 th Ed., Stultz and Kitto, Eds., © 1992 The Babcock & Wilcox Company, particularly to Chapter 26—Chemical and Heat Recovery in the Paper Industry, the text of which is hereby incorporated by reference as though fully set forth herein.
[0032] Referring to the drawings generally, wherein like reference numerals designate the same or functionally similar elements throughout the several drawings, and to FIG. 3 in particular, in its broadest form the process of the present invention begins with the atomization, partial combustion and gasification of a mixed organic/inorganic waste stream (Stream 272 ) resulting from the digestion of wood or other lignocellulosic materials. An oxidant (Stream 274 ) such as air or oxygen is used for the partial combustion.
[0033] This process takes place in suspension in a gasifier vessel 270 that is operated at above-atmospheric pressure, typically up to 800 psia, preferably between 300 and 600 psia. The hot fuel gases produced proceed to a quench zone 226 where a spray comprising process water and condensate (Stream 229 ), preferably a sulfide-lean quench liquor, rapidly cools the fuel gases. These quenched, sour, dirty fuel gases (Stream 3 ) will have sufficient heating value for use in a gas turbine, schematically indicated at 110 . However, they will also contain alkali fume, carbonaceous aerosols, and reduced sulfur compounds that must be removed before the fuel gas can proceed to the gas turbine.
[0034] The particulate in the fuel gases will be predominantly sub-micron aerosol. The fuel gas first proceeds to a particulate removal stage 104 where up to 99.9999% (six nines control) of the alkali fume and carbonaceous aerosol are removed. Although this level of particulate removal is extreme, it is necessary to meet the very tight specification for alkali contamination of fuel gases entering the gas turbine 110 . This particulate cleanup stage 104 will comprise a combination of one or more inertial-type dust collectors and may include an electrostatic dust collector/agglomerator to meet the most severe particulate requirements. For details of one such type of particulate removal equipment, reference is made to the aforementioned U.S. Pat. No. 6,238,459. Upon exiting from the particulate removal stage 104 , the fuel gases (Stream 4 ) will then proceed to a system generally designated 205 for removal of H 2 S from the fuel gas and which is designed for high selectivity of H 2 S over CO 2 . System 205 includes a process unit 202 designed to remove H 2 S from the fuel gas, and preferably comprises an absorption step or H 2 S scrubber and one or more stripping steps at 207 . The fuel gases, after passing through the H 2 S absorption step (Stream 5 ), will proceed into the gas turbine 110 or other suitable power generation equipment such as a steam generator. In the power generation equipment, any residual H 2 S in the fuel gas will be oxidized to SO 2 . SO 2 emissions resulting from the power generation step will be held below environmental emission limits by controlling the efficiency of the upstream H 2 S removal system 205 .
[0035] In the gasifier 270 , where the organic portion of the waste was gasified by partial combustion and the water shift reaction, the inorganic alkali portion of this stream 278 will be liberated as a stream of molten salts. In the context of a kraft recovery process, the molten salt stream at 278 is referred to as smelt. This stream 278 consists principally of sodium carbonate and sodium sulfide. Much of the molten salts will impinge on the walls of the gasifier 270 and flow by gravity towards the quench zone 226 . Some relatively coarse droplets of molten salts will remain suspended in the fuel gas, but both of these streams will be effectively captured in the quench zone 226 . The fume and carbonaceous aerosol will not be efficiently captured in the quench zone 226 but will instead proceed along with the fuel gas and be collected by the particulate removal stage 104 described above. The molten salts produced by this high temperature, high-pressure gasification process will be lean in sodium sulfide when compared with those produced in a conventional Tomlinson boiler. The aqueous fluid stream 229 used for quenching the fuel gas will consist of condensate containing dissolved fume (Stream 11 ) and a weak alkaline process water stream commonly referred to in the industry as weak wash (Stream 228 ). This stream 228 , in turn, comes from the washing with fresh water at 116 of the calcium carbonate precipitate (a.k.a. lime mud) that is created from a causticizing operation 312 to be described. The fluid used in the quencher 226 is thus a sulfide-lean quench liquor.
[0036] The sulfide-lean quench liquor 229 , when combined in the quencher 226 with the molten salts at 278 from the gasifier 270 , will form a solution of principally sodium carbonate, sodium disulfide and either sodium bicarbonate or sodium hydroxide. This solution is known in the kraft pulp and paper industry as green liquor or, more broadly, as carbonate liquor. Since the molten salts from which the carbonate liquor is formed are lean in sodium sulfide, so is the carbonate liquor (Stream 230 ), especially when compared to the carbonate liquor formed in the conventional kraft recovery process. This sulfide-lean carbonate liquor (Stream 230 ) is next taken to the causticizing plant 312 where the carbonate liquor first contacts powdered lime (Stream 34 ) in a conventional slaker-causticizer. The purpose of the slaker-causticizer 312 is to react slaked lime (calcium hydroxide) with aqueous sodium carbonate to form solid calcium carbonate and aqueous sodium hydroxide. A competing and undesirable reaction is between solid calcium hydroxide and aqueous sodium sulfide to form solid calcium sulfide and aqueous sodium hydroxide. Since the carbonate liquor (Stream 230 ) of the invention is lean in sodium sulfide, the causticizing is therefore more efficient when compared to a conventional kraft recovery process. Therefore, the amount of undesirable carbonate that stays with the caustic liquor (a.k.a. white liquor) (Stream 9 ) following the causticizer 312 will be less here than in a conventional process.
[0037] The caustic liquor (Stream 9 ) produced in this causticizer 312 is deficient in sulfide (i.e., sulfide-lean) when compared to conventional kraft recovery processes. For some pulping processes this would be a desirable trait. However, for the conventional kraft recovery processes, high sulfidity caustic liquor is preferred. Sulfidity is an industrial term, and is commonly defined as the molar ratio of HS − to (HS − +OH − ). To recover this sulfur value to the caustic liquor, it will be necessary to contact a portion of this caustic liquor (Stream 9 ) with the acid gases from the H 2 S stripper 207 (Stream 234 ). In order to do this without overly carbonating the caustic liquor (Stream 9 ), it is necessary that the molar ratio of H 2 S to CO 2 in Stream 234 coming from the H 2 S stripper 207 be greater than about 2. The influence of the H 2 S over CO 2 ratio on the caustic liquor (Stream 9 ) composition can best be illustrated with an example. If a tray type absorption column is used to scrub the H 2 S and if the selectivity of H 2 S over CO 2 is say 10, then an absorption column that is designed to remove 99% of the H 2 S will remove approximately 37% of the CO 2 in that gas. In this example, it is assumed that the sulfide-lean caustic liquor (Stream 9 ) has a sulfidity of 12.3% and a carbonation extent of 13.7%. If that caustic liquor in Stream 17 contacts an acid gas (Stream 234 ) containing an H 2 S to CO 2 ratio of 2.0 in an H 2 S caustic liquor scrubber 236 , then the sulfide-rich caustic liquor (Stream 19 ) leaving the H 2 S contactor or scrubber 236 in this example would have a sulfidity of about 32.5% and a carbonation level of about 17.3%. The influence of the H 2 S to CO 2 ratio entering the caustic liquor scrubber 236 on the caustic liquor composition leaving the scrubber is illustrated in FIG. 4. The amount of carbonation of the caustic liquor (Stream 19 ) will depend therefore on the ratio of H 2 S to CO 2 in the acid gas (Stream 234 ) entering the caustic liquor scrubber 236 . It also depends on the selectivity of that scrubber 236 to absorb H 2 S in preference to CO 2 . Any number of commercially available absorption columns can be used for the selective absorption of H 2 S over CO 2 . The caustic liquor, (sulfide-rich white liquor-Stream 19 ) upon leaving the scrubber 236 , is suitable for use as pulping liquor without any further treatment.
[0038] A typical fuel gas (Stream 4 ) composition entering the H 2 S removal system 205 is depicted in Table 1.
TABLE 1 COMPONENT MOLE % H 2 O 0.69 H 2 34.48 N 2 0.63 Ar 1.41 CO 31.65 CO 2 26.79 CH 4 2.03 H 2 S 2.32
[0039] The ratio of H 2 S to CO 2 in this example is 0.0866. Recall from above that the H 2 S to CO 2 ratio needs to be about 2.0 or higher before contacting the caustic liquor (Stream 17 ).
[0040] The absorption-stripping operation therefore has two distinct functions. The first is to reduce the H 2 S concentration of the fuel gas 110 sufficiently so that when combusted in the gas turbine 110 the SO 2 concentrations in the turbine exhaust will be environmentally acceptable. The second function is to produce an acid gas stream with an H 2 S to CO 2 ratio of at least 2.0. This means that the H 2 S selectivity over CO 2 must be very high. Selectivity in this context is defined as the ratio of mass transfer coefficients, e.g. K g a H 2 S /K g a CO 2 . Using σ to represent this selectivity, it can be shown that the selectivity can be expressed in terms of transfer units, NTU where NTU can be approximated by:
NTU H 2 s S =−1n(1-ε) H 2 S
[0041] Then,
σ = N T U H 2 S N T U CO 2
[0042] If in this example the H 2 S concentration leaving the scrubber 202 must be lowered from 2.32% to 100 ppm, that will require a removal efficiency of ε=1-0.0001/0.0232=0.9957 or 99.57%. Conversely, the CO 2 removal efficiency must be exceedingly low. If the acid gas is to have a ratio of H 2 S to CO 2 of 2, then no more than 2.32×0.9957/2 moles of CO 2 can be absorbed (about 1.16 moles CO 2 ). Therefore, the CO 2 removal efficiency must not exceed 1.16/26.79, or 4.33%. Then the required selectivity must be:
σ = - l n ( 1 - .9957 ) - l n ( 1 - .0433 ) = 123.1
[0043] This selectivity of 123.1 is beyond the capability of conventional absorption-stripping processes known to the inventors. A conventional absorption-stripping process or system is meant to imply a single absorption tower coupled with a single stripper tower. Even sterically hindered tertiary amines are capable of H 2 S to CO 2 selectivities of no better than about 30.
[0044] A system that is capable of achieving adequate selectivity is the SELEXOL process.
[0045] SELEXOL is a trademark of UOP Canada Inc., Toronto, Canada, for its process of scrubbing H 2 S. This commercially available process incorporates the use of a physical solvent and therefore absorbs various acid gas compounds in proportion to their partial pressure. The SELEXOL solvent itself is proprietary. Solvent regeneration is by pressure letdown of rich solvent. The solvent can be regenerated without heat. However, to reduce treated gas contaminants to low concentration, the solvent can be regenerated by a stripping medium such as an inert gas, or regeneration can be enhanced by the application of heat. Additional information concerning the publicly available SELEXOL process can also be found in HYDROGEN PROCESSING, April 1998, page 123.
[0046] A generalized SELEXOL process flow diagram is depicted in FIG. 5. Feed gas enters an absorber 501 where contaminants are absorbed by the SELEXOL solvent. Rich solvent from the bottom then flows to a recycle flash drum 502 to separate and compress 503 any co-absorbed product gas back to the absorber. Further pressure reduction on the drum 504 releases off gases. In some applications, the solvent is regenerated in a stripper column 505 . The regenerated solvent is then pumped through a cooler 506 and recycled back to the absorber 501 .
[0047] The gases leaving the H 2 S removal process such as the SELEXOL process are passed to a tower ( 236 in FIG. 3) where they are contacted with a portion of the sulfide lean caustic liquor (Stream 17 ) in FIG. 3. By proper design of this caustic liquor absorption tower 236 , a selectivity of H 2 S over CO 2 of about 10 to 15 is achievable. By designing this absorption tower to remove 99 + % of the H 2 S, the tail gases leaving this tower (Stream 7 ) can be taken directly to the lime kiln 316 for incineration or they can be delivered to the pulp mill□s non-condensible odor control system.
[0048] The SELEXOL solvent and process can be obtained from UOP Canada Inc. of Toronto Canada. There are SELEXOL processes which are available and which can be tailored to specific applications to enhance process performance. In the particular case of spent liquor gasification, the feed gas typically has a H 2 S/CO 2 ratio which is less than 1:20. The requirement is for selective H 2 S removal to less than 100 ppmv in the product gas while minimizing CO 2 co-absorption, such that the resulting acid gas to sulfur recovery has a H 2 S/CO 2 ratio of at least about 1:1. See FIG. 4. In order to accomplish these goals effectively, the basic SELEXOL process is modified to a more specialized process illustrated in FIG. 5 that involves both selective absorption and selective desorption/regeneration.
[0049] The person having ordinary skill in this art can therefore practice the SELEXOL process, H 2 S removal aspects of the present invention based on publicly available information.
[0050] An alternate to the SELEXOL process which removes more H 2 S than CO 2 is to subject the gases to a plurality of absorption-stripping units connected in series. For example, suppose that a conventional absorption-stripping system based on methyldiethanolamine (MDEA) were designed to contact the H 2 S bearing fuel gas to achieve the desired level of H 2 S control. If the fuel gas contained 1 part H 2 S per 23 parts CO 2 , the acid gas evolved from the stripper portion of the absorption-stripping unit could achieve a H 2 S to CO 2 ratio of about 1 part H 2 S to 1.8 parts CO 2 . If this acid gas is now taken as the feed gas to a second absorption-stripping set, then the H 2 S to CO 2 ratio achievable could be about 1.9:1. If a still higher ratio of H 2 S to CO 2 is desired before contacting the acid gas with caustic liquor, as in tower 236 of FIG. 3, then a third absorption-stripping unit could be used. FIG. 7 illustrates one form of such a plurality of absorption-stripping units connected in series. As shown, stream 22 is the acid gas product from the first absorber-stripper set. Stream 22 becomes the feed to the second absorber-stripper set, whose output is the acid-gas stream 234 provided to the H 2 S caustic liquor scrubber 236 .
[0051] The principal improvement of the process of the invention is the ability of this gasification system to recover the H 2 S from the fuel gas generated by gasifying spent liquor without increasing the burden on the causticizing system. The principal advantage has to do with savings in energy, i.e. fuel oil, that is required to calcine calcium carbonate that is produced in the causticizer. This advantage is derived by adding an intermediate step in the H 2 S recovery system, i.e. the SELEXOL process or equivalent, that first creates an acid gas stream with a high H 2 S to CO 2 concentration before contacting the acid gas with caustic liquor. A more conventional approach to H 2 S recovery is depicted in FIG. 6. Here the fuel gas stream 400 is contacted directly with a mixture of weak wash 402 and caustic liquor 406 in a multistage tower 404 . Because the CO 2 concentration is so much higher than the H 2 S concentration, most of the caustic that was produced in the causticizer 312 is consumed by the absorption of CO 2 . Therefore, that extra CO 2 must be recycled to the causticizer through the quencher via streams 412 and 414 and that CO 2 is therefore discharged through the lime kiln stack. Calcining of calcium carbonate is a highly energy intensive process and therefore creates a significant burden on the energy efficiency of this process. Moreover, many kraft pulp and paper mills have limited lime processing capacity in their rotary kilns 410 . The additional amount of calcium carbonate that must be handled may require additional capital investment.
[0052] A second advantage of the present invention concerns the ability to produce both high sulfidity and low sulfidity caustic liquor. The portion of sulfide-lean caustic liquor used to recover sulfur from the acid gas becomes saturated with HS − ion. This sulfide rich caustic liquor can be used advantageously to improve pulp properties by application to wood early in the kraft digestion process. It can alternately be blended with lean caustic liquor (Stream 118 in FIG. 3) to produce a conventional caustic liquor (Stream 120 ) of typical sulfidity and carbonate content.
[0053] In FIG. 8, another process and apparatus contemplated by the present invention is shown. The apparatus includes several elements that are common to the generic BLG process depicted in FIG. 2. In its broadest form the process of the present invention begins with the atomization, partial combustion and gasification of a mixed organic/inorganic waste stream resulting from the digestion of wood or other lignocellulosic materials. An oxidant such as air or oxygen is used for the partial combustion.
[0054] A gasifier 270 of the invention is required, and preferably comprises a water jacketed, refractory lined vessel where a waste stream produced by the digestion of lignocellulosic materials, such as black liquor 272 , typically containing less than 40% water is atomized and partially combusted with an oxidant 274 , such as air or preferably oxygen or mixtures thereof. The gasifier 270 operates in a pressure range from atmospheric up to 800 psia, and preferably 300 to 600 psia. A stream 278 leaving the gasifier 270 will be in the temperature range of 1600 to 2200 F., typically about 1800 F. and comprises fuel gas 276 constituents, molten salts referred to in the pulp and paper industry as “smelt” (in a kraft recovery process), and a sub-micron sized mixture of alkali fume and soot. The molten smelt comprises relatively large molten droplets and/or streams which flow down the walls of the gasifier 270 towards a quencher 226 . In the quencher 226 , a relatively coarse spray comprising a mixture 229 of weak wash 228 (a slightly alkaline solution) and condensate with dissolved fume 200 , is used to cool the fuel gas 276 to its adiabatic saturation temperature, which is typically in the range of about 300 to 400 F. While the evaporative cooling takes place in the quencher 226 , the smelt constituents are collected quantitatively by the quench spray and dissolved therein. The resulting mixture 230 is sulfide lean and is known as green liquor. This stream 230 of green liquor will be subsequently causticized to white liquor in the slaker/causticizer 312 . That portion of the process will be described in more detail later.
[0055] The raw fuel gas 276 , upon leaving the gasifier quencher 226 , will typically contain about 3500 ppm of H 2 S, about 8% CO 2 , a water content of over 1.75 lbs H 2 O/lb dry gas, and a fume concentration as high as 800 grains per ft 3 of fuel gas 76 . To be an acceptable fuel gas for a gas turbine, the fume concentration in the fuel gas 276 must be reduced to less than about 0.0024 grains/ft 3 . To accomplish that feat, a three-step process 280 (shown in greater detail in FIG. 9) is employed according to the present invention.
[0056] Referring now to FIG. 9, in the three-step fume reduction process and apparatus 280 , a first venturi scrubber 282 first contacts the fuel gas 276 . The venturi scrubber 282 depicted in FIG. 9 will typically operate at a pressure drop of about 2 to 5 psi. Scrubber 282 uses a circulation of water 288 from a circulation pump 290 , for example, through venturi 286 where the aqueous spray contacts the fuel gas 276 in the throat of the venturi 286 . The water 288 may be taken from the quencher stream 100 . The relatively high gas velocity (>200 ft/sec) and low liquid flow rate (<1 lb liquid/lb gas) promotes atomization of the liquid in the venturi throat and subsequent inertial impaction between the liquid droplets and the fume particles in venturi scrubber enclosure 284 .
[0057] The purpose of this first venturi scrubber 282 is to reduce the dust loading of the fuel gas 276 to less than about 8 grains/ft 3 . Following this venturi scrubber 282 the fuel gas 276 is cooled (schematically indicated at 91 in FIG. 9) and the water content is reduced to less than about 0.35 lb H 2 O/lb dry gas. Three separate approaches are available for this task. First, the fuel gas 276 can be cooled in a heat exchanger 291 , advantageously a condensing heat exchanger, using cold, high-pressure process water from the mill or another source such as a cooling tower. After exiting the heat exchanger 291 , the cooling water will be heated sufficiently for use in resaturating the fuel gas 276 after the H 2 S removal operation (at 206 ) as described below. Thus, energy removed from the fuel gas 276 during the particulate control operations can be efficiently returned to the fuel gas later in the process. Alternatively, the fuel gas 276 can be cooled in the first venturi scrubber 282 by using cooled water from 289 as the aqueous spray 288 . The heat absorbed by this water in the venturi scrubber 282 can be rejected by a liquid-to-liquid heat exchanger. The water condensed from the fuel gas 276 in this manner leaves the venturi 286 as blowdown 201 . In a further alternative, the fuel gas 276 can be passed through a boiler 291 to generate steam for use within the paper making process. The reduction in water content of the fuel gas 276 from 1.75 to 0.35 lb H 2 O/lb dry gas represents a greater than 50% reduction in total volumetric flow rate of fuel gas 276 . Thus, the fuel gas treatment equipment to follow is greatly reduced in size.
[0058] The fuel gas 276 with the dust loading reduced to less than 8 grains/ft 3 enters an electrostatic agglomerator-venturi scrubber arrangement depicted in FIG. 9. The electrostatic agglomerator (ESA) 292 is sized to collect at least 99.9% of the fume and soot not captured by the first venturi scrubber 282 . The ESA 292 is designed to temporarily retain the collected material on the walls of its collection tubes 294 whereby it is re-entrained by the suitable use of rappers (not shown). A second venturi scrubber 296 subsequently captures the agglomerated solids. A source of water from quench stream 200 , and a blowdown stream 203 may be employed as described above in connection with the first venturi scrubber 282 . For details of one such type of particulate removal equipment 280 , reference is made to the aforementioned U.S. Pat. No. 6,238,459.
[0059] Upon leaving the particulate control section 280 , sour fuel gas 98 will contain about 7700 ppm H 2 S and about 17% CO 2 . The temperature will be about 325 F. This fuel gas 298 temperature is too hot to be effectively treated by conventional absorption-stripping processes for H 2 S removal.
[0060] To accomplish adequate H 2 S removal performance requires that the fuel gas 298 be cooled further. This cooling preferably takes place in another heat exchanger 299 again preferably a condensing heat exchanger, to cool the fuel gas stream 298 . Leaving the heat exchanger 299 , the fuel gas 298 water content has been lowered to about 0.01 lb H 2 O/lb dry fuel gas. The H 2 S concentration is raised to 10,900 ppm and the CO 2 concentration is 24.4%.
[0061] The water condensed from the fuel gas stream in the two heat exchangers 291 , 299 (or alternate devices as described) and blowdown streams 201 , 203 from the two venturi scrubbers 282 , 296 are collected and sent to the quencher stream 200 . The purpose of this aqueous stream is to control the concentration of salts in the green liquor 230 . The pulp and paper mill requires that the green liquor salt concentration be within a specified range; typically 120-130 g/L as Na 2 O. The water collected from the two venturi scrubbers and the heat exchangers is also contaminated with low levels of salts from the alkaline fume carryover. By taking this water back to the quencher 226 , all alkali compounds are returned to the process.
[0062] The sour fuel gas 298 next enters an absorption column 202 (part of a sulfur removal system generally designated 205 ) where H 2 S is preferentially absorbed from the fuel gas 298 . The column 202 is designed to remove over 99% of the H 2 S in the fuel gas. Some CO 2 is also removed from the fuel gas 298 in this absorption column. Chemical solvents such as methyldiethanolamine, MDEA, or a physical solvent such as the SELEXOL solvent can be used here.
[0063] The fuel gas 298 leaving the absorption column at 204 is next contacted with a stream of hot water and/or steam at 206 . The hot water can come from the condensing heat exchanger 291 after the first venturi scrubber 282 as described earlier. The purpose is to produce reheated and humidified fuel gas 209 which is provided into a gas turbine 210 . The fuel gas 209 is heated to a suitable temperature for the selected gas turbine. For example, for a General Electric Model 6FA gas turbine the fuel gas 209 is reheated to about 385 F., a water content of about 0.5 lb H 2 O/lb dry fuel gas, and a pressure of about 300 psia. At the gas inlet of the turbine combustor 212 these gases are throttled before mixing with the combustion air in such a manner that the combustor 212 operates at about 50 psi below the fuel gas 209 inlet pressure. The gas turbine 210 is coupled to both an electric generator 217 and to a compressor 218 which supplies combustion air 216 to the combustor 212 at the operating pressure of the combustor 212 . The system is flexible and can easily accommodate other gas turbine requirements.
[0064] The hot exhaust gases 220 leave the gas turbine 210 at a temperature above about 1000 F. These gases 220 contain in excess of 10% oxygen. Since these gases 220 are well above the auto-ignition temperature of natural gas, additional heat can be added to the turbine exhaust gases 220 by contacting these gases with natural gas in a duct burner 222 . In this manner, the gases can be heated to above 1500 F. before entry into a waste heat boiler 224 . This permits the generation of high pressure steam at, for example, 1250 psi and 925 F., but again other steam cycles can be used. This steam is suitable for use in a back pressure steam turbine 226 to produce electric power via electric generator 227 , and also process steam.
[0065] The recovery and reuse of sulfur that began with the H 2 S absorption column 202 described above is more particularly accomplished in the manner described here. The solvent used in the absorption step is transferred to a stripping column 207 where the pressure is reduced preferably to less than 30 psia. The solvent is then regenerated by heating. The combination of low pressure and high temperature causes the absorbed H 2 S and CO 2 to evolve from the solvent into the gas phase. This unit operation is known as solvent regeneration. The gas 234 that evolves from the stripping column 207 is referred to as acid gas since it contains mostly H 2 S and CO 2 . The lean solvent leaving the stripping column is cooled and pumped to the pressure of the absorption column 202 for reuse. The cooling is accomplished by contacting the lean solvent with the rich solvent in a liquid-liquid heat exchanger or an air cooled heat exchanger.
[0066] The H 2 S selectivity of the absorption-stripping process is critical. The ratio of H 2 S to CO 2 in the raw, sour fuel gas 298 entering the absorption column will be on the order of 1 part H 2 S to 20 parts CO 2 on a molar basis. The H 2 S to CO 2 ratio in the acid gas leaving the steam stripper must be at least 1 part H 2 S to 1 part CO 2 . A ratio of 4 parts H 2 S to 1 part CO 2 or higher is preferred. The SELEXOL process, available from UOP Canada Inc., Toronto, Canada, is one of the processes capable of this degree of H 2 S selectivity. SELEXOL is a trademark of UOP Canada Inc. for its process and a solvent used in the process. The acid gases 234 are next contacted with sulfide lean white liquor 240 in an absorption column 236 designed to have a high selectivity for H 2 S absorption over CO 2 . In this manner, the sulfide can be returned to the pulping liquor stream as white liquor 238 without significant carbonation thereof. The white liquor 238 can in this manner be used directly in the pulping process without further chemical processing.
[0067] As described above, the production of pulping liquor for the digestion of wood chips begins (in the context of a black liquor gasification process) with the production of green liquor 230 in the quencher 226 . Recall from above that the green liquor 230 was produced when the smelt constituents dissolved into the mixture 229 of weak wash 228 and condensate with dissolved fume 200 and recycle water during the quenching operation. The green liquor consists of a mixture of sodium carbonate, sodium hydroxide, and sodium sulfide. The weak wash 228 is produced when fresh water is used to wash white liquor from the filter cake of calcium carbonate that is produced in the causticizing operations at 312 . This weak wash is shown as stream 228 in FIG. 8. From a chemical composition standpoint, the weak wash 228 can be thought of as dilute white liquor. The recycled water contains low levels of alkali compounds from the fume carryover. The recycled water is shown as stream 200 in FIG. 8. The calcium carbonate is produced as a suspended solid when green liquor contacts an aqueous suspension of calcium hydroxide in the causticizing plant 312 . The solid calcium hydroxide reacts with the dissolved sodium carbonate to produce dissolved sodium hydroxide and solid calcium carbonate.
[0068] Soot (a sub-micron sized carbonaceous aerosol) that is caught by the venturi scrubbers 282 and 296 is removed from the aqueous phase at the mud filter 338 leaves the process by combustion in the lime kiln 316 .
[0069] The green liquor stream 230 leaving the quencher 226 differs substantially from that of a conventional kraft recovery process as illustrated in FIG. 1. Green liquor stream 230 in FIG. 8 will contain as little as 50% of the sulfide of a conventional green liquor. That situation results from the much greater partition of sulfur as H 2 S in the gas phase of the gasification process. This is one of the principal differences between black liquor gasification (BLG) and conventional kraft recovery. This difference provides the opportunity for several process improvements over conventional kraft recovery. First, the BLG scheme offers a causticizing improvement. One of the means by which sulfur is lost from the conventional kraft recovery process is through the precipitation of calcium sulfide (CaS). This precipitated CaS is separated along with the calcium carbonate (lime mud 340 ) on the vacuum filter 338 from the white liquor. This lime mud is then separated and taken to the rotary lime kiln 316 where any calcium sulfide co-mingled with the calcium carbonate is decomposed to CaO and SO 2. In the case of the present invention, since the green liquor is lean of sulfide, there is a proportionate reduction of calcium sulfide mixed with the lime mud sent to the kiln 316 .
[0070] Another advantage of the low sulfidity green liquor in the BLG process is the fact that the white liquor produced from this green liquor will have a proportionately lower sulfidity. If all of this sulfide lean white liquor in stream 240 of FIG. 8 is used to contact the acid gas in stream 234 , then by material balance constraints, the sulfidity of the white liquor in stream 238 would be equivalent to that of the conventional kraft recovery cycle. But, if only a portion of stream 240 contacts stream 234 , then a white liquor stream with a higher sulfidity can be generated along with a stream of lower sulfidity white liquor. This offers the plant operator certain pulping options that are not available with the conventional kraft recovery process.
[0071] There are various advantages of the present invention. The Tomlinson recovery boiler is the current standard method and apparatus for chemical recovery in the kraft pulping process. Recovery boilers are costly, prone to corrosion and catastrophic smelt-water explosions and are limited to relatively modest steam temperatures and pressures. These limits constrain the-ability of this standard technology to effect improvements in electric power production. Black liquor gasification is widely viewed as the technology most likely to replace the recovery boiler.
[0072] If pressurized and coupled with gas turbines, BLG systems can provide more efficient utilization of black liquor fuel value and produce more electrical power relative to steam. This is an attractive feature for future mills where higher electrical usage will be required to operate mechanical pulping and pollution control equipment. Smelt-water explosions are a serious risk associated with recovery boilers and most BLG concepts eliminate the possibility of these catastrophic events. Unlike recovery boilers, BLG systems recover sodium and sulfur as separate streams which can be blended to produce a wide range of pulping liquor composition. This increased process flexibility of BLG may be a significant asset in future kraft pulping operations.
[0073] In addition to the general advantages of black liquor gasification, the specific embodiment of the present invention offers advantages that constitute improvements over other BLG systems. Other BLG processes can cause a significant burden on the causticizing plant, because of co-absorption of CO 2 . This process avoids that problem by including the absorption-stripping process that greatly increases the ratio of H 2 S to CO 2 in the gas that contacts the white liquor. This process provides means to eliminate alkali fume problems that could be a problem in other BLG processes. The inventors believe that the fume generation and control shown in other BLG process patents significantly understate the severity of this problem. The process and apparatus described in the present invention can realistically reduce fume and aerosol emissions below the gas turbine allowable limits.
[0074] The rapid quench of fuel gas from 1800 F. to about 400 F. by adiabatic humidification represents a significant portion of the chemical energy in the black liquor, or other type of waste stream. The means used to reclaim that energy into useful form is a challenge for any BLG process. The use of a heat exchanger or boiler to raise process steam between the first venturi 282 and the ESA 292 is an efficient way to recover nearly all of that waste heat as low-pressure (nominally about 80 psig) steam. This steam can be used as process steam throughout the pulp mill.
[0075] Within the framework of the apparatus and process described by FIG. 8, several alternatives are possible. All involve suspension gasification followed by a rapid quench to saturation with water. How the heat is recovered from the process is one area where several options exist. A condensing heat exchanger could be used to raise the temperature of high-pressure water from about 130 F. to about 340 F. This hot, high-pressure water can then be contacted with the fuel gas in a saturator as at 206 . The excess water that is not evaporated into the fuel gas is cooled in a liquid-to-liquid heat exchanger, increased in pressure and sent back to the condensing heat exchanger thus forming a closed-loop system. In this embodiment, the heat that is not returned to the fuel gas in the form of water vapor is simply rejected from the system. In an alternate embodiment an economizer section from a boiler could be used in place of the condensing heat exchanger. Here, the fuel gas would generate low-pressure steam that could be used elsewhere in the paper plant.
[0076] The manner in which the fume and soot are collected in the process described in FIG. 9 is designed for the most severe range of particulate emissions likely to be encountered in black liquor gasification. If the dust loading from a particular gasifier were about two orders of magnitude below the estimate used for the design of this gasifier 270 , then the first venturi scrubber 282 could be eliminated.
[0077] The process by which the H 2 S is scrubbed from the fuel gas and delivered to the white liquor is subject to various possibilities. Although the SELEXOL process is the preferred means, other absorption-stripping processes are suitable for this gasification process. Sterically hindered tertiary amines such as methyldiethanolamine are one such compound that can be used in a conventional absorption-stripping process.
[0078] While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. | A method and apparatus for producing clean, sweet, fuel gas for use in a combustion process and for producing other useful products by processing a waste stream from digestion of lignocellulosic material. Essentially, the waste stream is partially oxidized to form hot gases and molten salts. The hot gases and molten salts are then cooled using a quench liquor to form quenched gas and carbonate liquor. Particles are removed from the quenched gas to form a raw fuel gas, preferably by subjecting the quenched gas to a multi-step fume reduction process which includes heat extraction from the quenched gas to reduce particulate load and water content of the quenched gas to form a low fume fuel gas. H 2 S is removed from the low fume fuel gas using an H 2 S removal process which is more selective for H 2 S than it is for CO 2 , the removing step forming clean, sweet, fuel gas and acid gases. The clean, sweet, fuel gas may be conveyed to a combustion process, advantageously a gas turbine/electric generator couple and possibly to a heat recovery steam generator, and/or it may undergo further processing to form other useful products. Likewise, the acid gases can be processed to form additional useful products. The optional multi-step fume reduction process passes the quenched fuel gas through a first venturi scrubber, an electrostatic agglomerator, and a second venturi scrubber in series. | 3 |
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for positioning and mounting large installations on the seafloor or on mainland.
Examples of such positioning/mounting operations are the mating operation for a large offshore structure onto a previously mounted template on the seabed, or the mating of building-like structures onto a structure already standing on the ground, and where separately installed directing or docking piles are used. For reasons of simplicity, mainly seabed operations will be dealt with in the following.
A typical such mating operation may involve a supporting structure or "jacket" that is to be lowered down in order to be secured in a predetermined position on/above a template or an equivalent structure. The jacket shall be maneuvered downwards so that docking sleeves suitable for use therewith can be threaded down onto docking piles which have been driven or drilled down into the seafloor around the template, in order that the jacket may be placed exactly in position over the template. Two conflicting requirements are always presented in connection with mating operations of this kind.
On the one hand, there exists a requirement that the horizontal deviation between jacket and template be as small as possible in relation to the completely ideal position, this in order to secure the subsequent tieback operation, i.e. the coupling together of conductor strings to the already completed wells (well heads) in the template.
On the other hand, one would like to have large horizontal clearances or tolerances in the guiding system, i.e. between the docking piles and the guiding or docking cylinders which are to be threaded down onto the piles in order to simplify and secure the operation itself, which operation is critical regarding weather, wave and current conditions.
Traditionally a compromise is made, and one selected tolerances in the guiding system to make the mating operation feasible within a specified "weather window" based upon statistics on such conditions.
The previously known techniques regarding such positioning and mating is principally based upon three systems, all using two or more docking piles to effect guidance both "sideways and directionally" during the mating operation. As previously mentioned, these piles have been installed in advance. They have been driven or drilled down into the seabed under guidance from guide members mounted for instance on the ends of the previously mounted template. Then the jacket is floated or hoisted in above these docking piles.
A) "Fixed" system: When hoisting the jacket down, an open cylinder, the docking sleeve, which is fixed to the jacket, is firstly guided down onto the corresponding one of the docking piles. Thereafter the jacket is rotated until the other docking sleeves are in position right above their corresponding docking piles. Then, the jacket is lowered down the last part of the way, until the jacket is standing in its position on the seabed.
B) "Active" system: This system is similar to the "fixed" system above; however, the docking sleeves are mounted loosely each in a respective fixed cylinder, i.e. the docking sleeves may be moved vertically. The loose docking sleeves are suspended by respective wires, and thus may be lowered individually down onto the corresponding docking piles. In this system there is a possibility of raising the docking sleeves again if necessary.
C) "Passive" system: This system is also similar to the previous one; however, the loose docking sleeves are not suspended by wires and therefore cannot be re-raised.
The previously used systems are burdened with several drawbacks.
The ultimate and essential point is being able to achieve the joining together of the oil conductor strings belonging to the platform and the pipes protruding up through the template (i.e. the tieback operation). Because of the above-mentioned compromises, which must be made regarding tolerances in the dimensions of piles and sleeves as well as in the positions and angles thereof, angular deviations as well as deviations in position may become larger than advisable during the tieback operation. In other words, small tolerances for the tieback operation entail a greater risk when effecting the very critical mating operation, when using these prior art systems.
Moreover, with the known systems there exists a possibility that the parts may get stuck during the mating operation if the tolerances are exceeded. This may prove fatal.
As a secondary point, it should also be mentioned that the previously known sleeve system is always large and heavy, and in connection with these large steel structures it is also necessary to use corrosion preventing electrical systems of considerable size.
SUMMARY OF THE INVENTION
An object of the present invention is to obviate the drawbacks in the prior art so that the following advantages are gained.
The tolerances in connection with the tieback operation are radically improved.
The mating operation itself may be effected with a larger clearance, which simplifies the operation and makes it less critical. The mating operation is very critical per se, because the jacket is afloat during the operation and is exposed to changing weather conditions.
The present invention may employ a centering gimbal which is fixed by welding to each one of the docking piles. Such gimbals provide reduced local positional and angular deviations in relation to the guide members on the template when the piles are drilled down into and cemented to the seabed, compared to a pile without such a gimbal.
The preliminary analysis of the mating operation is simplified because the number of variables entering into the calculation is reduced, whereby the reliability of the analysis results may be increased. The traditional method of using long sleeves threaded down onto the piles results in a large number of possible combinations of stiffnesses, since the stiffness is changed the further down the sleeve is threaded onto the pile. There are also uncertainties in determining a single stiffness. When using the system in accordance with the present invention, only the stiffness of the pile itself is a variable parameter during the lowering of the sleeve, while the previous variations relating to the sleeve are eliminated.
There is achieved a weight reduction of the mating system of about 90% in relation to the sleeve systems used today.
As a consequence of this reduction in weight and surface area, a corresponding reduction of the number of corrosion preventing anodes is also achieved.
The production of the present system is clearly simpler than the conventional systems.
A further and apparent advantage of the system in accordance with the present invention is the cost savings which can be appreciated in connection with several of the items mentioned previously.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail below, referring to the enclosed drawings, in which:
FIGS. 1a-1c are schematic diagrams of previously known mating systems;
FIG. 2 is a schematic diagram of a traditional system with fixed sleeves;
FIG. 3 is a sectional view taken along line A--A in FIG. 2;
FIG. 4 is a view similar to FIG. 3 but of an embodiment of the positioning equipment in accordance with the present invention;
FIG. 5 is a schematic sectional view of the positioning equipment in accordance with the present invention as taken along line B--B in FIG. 4;
FIG. 6 is a cross-sectional view of a ring and slot in accordance with the invention;
FIG. 7a is a schematic diagram of docking piles equipped with centering gimbals, in accordance with the invention, as well as the corresponding reference positions thereof;
FIG. 7b is a similar view showing the above reference positions when using an alternative system without gimbals;
FIG. 8 is an explanatory diagram illustrating a sequence of different stages during a lowering operation in accordance with the invention;
FIG. 9 is an explanatory diagram illustrating a few of the sources of error which a traditional system must take into consideration;
FIG. 10a is a force diagram of the static system when using traditional equipment;
FIG. 10b is a similar diagram illustrating the static system when using the equipment in accordance with the invention; and
FIG. 11 is a schematic diagram of another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIGS. 1a-1c there are shown previously known techniques of positioning large structures on the seafloor, as mentioned above. All three of the solutions which have been sketched are based upon the use of large sleeves which are threaded down onto docking piles in order to direct the structure into its position. The present invention does not depend upon such sleeves, as will become apparent from the description below.
FIG. 2 also shows a traditional system using fixed sleeves 3, as in FIG. 1a. The angle a between the axes of the two pipes 6 and 7, as well as the sideways deviation δ, are parameters to be minimized in connection with the tieback operation. The docking sleeves 3 are long cylinders extending between two lower portions of horizontal bracings of the structure 1, and they are threaded down onto docking piles 4. A frame or template 2 mounted on the seafloor forms a starting point for the installation of the piles 4 in the seafloor 5. Thereafter, guide members (not shown) are removed by burning and are hoisted away from the remaining stumps 8, so as to avoid transmitting the shock loads from the mating operation through the bottom template itself and thereby inflicting damage to the well heads.
FIG. 3 is a plan view of the system of FIG. 2, or is a view along section line A--A in FIG. 2. The docking piles 4 are shown in black inside the sleeves 3.
In FIG. 4 the central parts of the positioning equipment in accordance with the present invention are shown in a view similar to that of FIG. 3; however, the template has been left out for the sake of clarity. The docking piles 4 are also shown in black.
FIG. 5 is a side view of the positioning equipment. The central features of the invention are as follows.
The docking sleeves (3, FIGS. 2 and 3) have been exchanged for a guide ring 10 and a guide frame with a rectangular slot 11. The ring 10 and the slot 11 are in this case located in the same plane, for instance as shown in FIGS. 4 and 5, in the lower bracing. However, it is equally possible to dispose the ring and slot in respective horizontal planes, vertically spaced from each other. Furthermore the guide slot 11 is arranged in such a manner that its longitudinal center line is directed to the center of the ring 10. Both the ring and slot are suitably defined by downwardly opening directing parts for reception of the docking piles 4. Thus, the guide ring 10 comprises a conical directing collar 10a with a lower and larger diameter D 0 , which directing collar gradually tapers in a curved manner to an upper part having a smaller ring diameter d 0 , which upper part is fitted to the docking pile 4 (see FIG. 6). In a corresponding manner, the guide slot 11 is defined by a directing skirt 11a, which preferably has the same cross-sectional projected shape as the directing collar 10a, when viewing that section which is perpendicular to the above mentioned center line, in other words a view from the position of the guide ring 10. Thus, in this section one sees the same lower maximum opening D O and the same minimum opening d 0 . The "ring" and "slot" mentioned hereafter without further explanatory statement shall be understood as the ring and the slot where the openings are the smallest. When constructing these minimum openings it is only necessary to take into consideration construction tolerances of the piles and guide parts.
By making the lower opening (D 0 ) of the directing parts 10a, 11a (see FIG. 6) sufficiently large, the requirement for maximizing horizontal clearances/tolerances in order to secure the installation operation within a given "weather window", is complied with. A value of this largest opening may be calculated from the "mating analysis", i.e. from the movement characteristics of the structure during the mating operation.
The system itself with ring 10 and slot 11 eliminates the consideration for horizontal deviation on top of the docking piles (because of vertical deviation on the pile itself). See FIG. 8 in connection with FIG. 9. From FIG. 9 the increased tolerances which must be taken into consideration by the traditional sleeve system appear clearly, the highest points of the docking piles possibly being erroneously placed within margins as sketched, having dimensions d 1 , d 2 , respectively. When using the present system including the ring and slot, such erroneously positioned points do not pose a problem, since the ring will slide along one of the piles while the slot will, at the same time, allow a sliding movement along the other pile, independent of angular errors. At the same time it should be noted that the angles in the drawings have been partly grossly exaggerated in order to clarify these considerations.
Thus, the present invention utilizes the fact that the ring arrests the structure from moving in the xy-plane, while the slot stops or establishes the limits on rotation of the structure in the same plane. As previously mentioned, the ring and slot may thereby be constructed as narrow as desired, i.e. it is only necessary to take into consideration the construction tolerances of the ring, slot and piles.
In a preferred embodiment of the invention the system is constructed in such a manner that that point of a docking pile 4 which is to have the smallest horizontal deviation relative to the template 2, will be situated in the same level as the narrowest horizontal plane in the respective ring 10 and slot 11 of the structure 1 when the latter stands in its final position, i.e. on the sea floor. This is tentatively illustrated in FIGS. 7a and 7b, in which in both cases the horizontal deviation shall be minimized in relation to the distance x', which represents the theoretically correct horizontal distance between a reference point 15 on the template 2 and an ideal position 14 of the docking pile 4.
Thus, when looking at the arrangement according to FIG. 7b, the ring and slot shall in the end, i.e. when the structure 1 is standing on the seafloor 5, be disposed at the same level as the point 14. This requires of course that the guide members 12 have been removed prior to the mating operation, which removal is normally made by burning off and hoisting up the guide member 12 itself (see also FIG. 2, reference numeral 8).
The most preferred embodiment of the system according to the present invention is shown in FIG. 7a. Here the docking piles 4 have been equipped in advance with centering gimbals 13 which have been fixed by welding and are adapted to cooperate with the guide members 12. Such a centering gimbal provides a pile point 14 which deviates to an even lesser degree from its ideal position than the pile point 14 of FIG. 7b. Thus, in this manner it is possible to achieve a further reduction of the horizontal deviation in relation to the reference point 15. However, the welded gimbals 13 ensure that the guide members 12 cannot be hoisted up after burning. For this reason the guide members 12 are placed in a sufficiently high position on the template 2 that when burned off, they may fall down to the seafloor 5, thereby being brought such a distance from the parts of the structure 1 that when the latter is lowered down, said guide members 12 do not constitute an obstacle to the mating operation. It should be noted that loosely mounted gimbals are not always desirable, since these gimbals must be removed by means of some mechanical system. Furthermore it must be noted that FIG. 7b also shows guide members 12 in a high position, so that it is possible to utilize the advantage of merely dropping burnt-off guide members 12 down to the seafloor.
Thus, in the embodiment shown in FIG. 7a, the guide ring 10 and the guide slot 11 will be lowered down to the level indicated by the point 14, the structure 1 simultaneously reaching the seafloor 5. With the ring and slot in this level a minimum value of horizontal deviation is ensured. Accordingly it will be appreciated that the combination of features of the guide slot and guide ring, ensuring the positioning of the latter parts at the same level as the pile point 14 in question, as well as guide members located in a sufficiently high position and the use of centering gimbals, contribute to an essential decrease in the horizontal deviation possibly appearing between the structure 1 and the template 2. This is because that point 14 of a docking pile 4 which has the smallest horizontal deviation in relation to the template 2, determines the relative horizontal deviation for the structure 1 in relation to the template 2.
FIG. 8 shows a sequence of the different stages of the mating operation. Docking piles 4 with gimbals 13 have been drilled down in advance. Thereafter, the guide members have been burned off, and the latter are now lying on the seafloor (see reference numeral 16). The structure 1 to be hoisted down is equipped in its lower bracing with the ring and slot, in line with what is shown in the preceding drawings. The ideal horizontal distance (x', see FIG. 7a) from the reference point 17 in the template 2 to the ideal position of point 14 above the centering gimbal 13 on pile 4, is found to be the distance from point 18 in the structure to the center of the ring. It is now a goal to bring point 18 into horizontal coincidence with point 17, i.e. point 18 is supposed to be finally located exactly vertically above point 17. From phase I, the structure 1 is lowered with the ring 10 down towards the top of the left-hand docking pile, the size of the lower opening of the directing collar 10a securing and simplifying this operation. The lowering down of the structure continues through phase II, the ring following the pile downwards with a small clearance therebetween. At the same time the structure 1 is now adjusted rotationally about the left pile, so that an accommodation of the slot (to the right in the figure) onto the right-hand pile is achieved. The directing skirt of the slot simplifies an allowance of small movements in the critical moment of the mating, i.e. just before phase III. During further lowering, the structure is guided by both ring and slot which are situated around their respective docking piles. When the lower parts of the structure touch the seafloor and stop, the ring and slot are located in the same level as point 14. The possible horizontal deviation now existing regarding point 18 in relation to point 17, is due to errors in the position of the center of the ring relative to the ideal position of point 14, for instance. As mentioned previously, these errors have now been minimized.
In FIGS. 10a and 10b, a coarse and simplified comparison is shown between the traditional configuration with a sleeve and the configuration in accordance with the present invention, regarding the "static system". In the traditional configuration, (FIG. 10a) two engagement spots appear for a docking pile inside a docking sleeve, shown by arrows F 1 and F 2 . In comparison, only one engagement spot appears in the configuration in accordance with the present invention, shown by the arrow F 3 . The deformed condition of the docking pile in the two cases is shown symbolically at respective sides of the figures. Analytically, the configuration in accordance with the present invention (FIG. 10b) constitutes an essentially simplified system. As previously mentioned in this specification, the mating analysis comprises a number of variable parameters, for instance stiffnesses. The number of possible combinations of stiffnesses constitutes a problem since stiffnesses are changed as the sleeve slides further down onto the pile. In addition there exist uncertainties when determining a single stiffness. Since the system in accordance with the invention only has one engagement spot, the stiffness of the slot or ring does not change, but only from the pile itself during the lowering operation. Since the number of variables in the analysis is reduced, the reliability of the analysis results is also increased.
In the figures, the structure 1 to be lowered is shown in the form of a typical steel jacket. However, the invention finds general application in installing any structure on the seabed or on mainland, when sideways tolerances are of vital importance. Typical examples are, in addition to the illustrated jacket and template, a concrete platform, a protecting structure or an underwater installation on top of a frame or template.
When comparing two actual cases, namely the Oseberg-B Jacket and the Oseberg-II Wellhead Platform, as existing in May 1987, calculations have been made to show a reduction in the tieback moment which can be transformed directly into tolerances, of about 70%. However, it must be noted that lesser parts of this reduction are due to other matters than those related to the invention, namely the use of three piles instead of two. However, on the other hand "as installed" tolerances, i.e. known and certain tolerances were applied regarding Oseberg-B, while in the Oseberg-II calculation example all theoretical uncertainties were taken into consideration, i.e. larger uncertainties. Accordingly, this resulted in a conservative calculation of the reduction in tieback moment.
The invention has been referred to previously in this specification as a "fixed" system (compare the prior art techniques mentioned in the introductory part of the specification). However, variants of the principle according to the invention, i.e. including the ring and slot, may also be constructed starting from the previously mentioned "active" and "passive" systems.
For example, both the slot and ring, or possibly only one of these members, may be constructed to be movable and thereby the effect of these movable systems is achieved. The characteristic feature of the movable systems (active/passive) is that they are able to enclose the docking pile rapidly when the construction has been brought into position, in addition to the fact that the structure is made less sensitive to vertical blows from the docking pile against the guide part of the structure, which docking pile may thrust into the edge under unfortunate circumstances.
The slot and the ring in accordance with the present invention may, for instance, be constructed as movable elements simply by placing the previously described directing collars inside a larger cylinder which corresponds to the traditional docking sleeve, whereafter the docking sleeves can be hoisted and lowered as desired. In this connection, FIG. 11 shows docking sleeves 19 which can be lifted up and down by means of wires 20, and where the docking sleeves have directing collars 10a, 11a, in accordance with the present invention, located inside the docking sleeves.
As previously mentioned, the invention may also be realized by disposing the ring and the slot at different levels in the structure to be lowered, on the condition that the heights of the two piles are adapted to such a situation. As long as the ring can be threaded onto "pile no. 1" first, and thereafter a possibility exists for rotation in order to fit the slot down onto "pile no. 2", the invention will be able to function as intended in this regard. The point is that the guide member and the guide part (i.e. ring or slot) in the final stage are supposed to be located at the same level for each single pile.
Nor are a directing collar/directing skirt for the ring and the slot necessary features per se, but practical additional features of the invention. A corresponding directing effect during the mating operation is also achieved for instance by sharpening or rounding the tops of the docking piles. | A system for positioning and mounting a large structure over a template lying on the ground or on the seafloor, uses a guide ring and a guide slot, both fixed to the structure, for guiding and holding onto two docking piles during a mating operation. These piles have been driven or drilled down into the seafloor/ground in advance through guide members fixed to the template. | 4 |
STATUS OF RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No. 12/038,017, filed Feb. 27, 2008, now pending, which is a divisional of U.S. Ser. No. 11/065,415, filed Feb. 24, 2005, now U.S. Pat. No. 7,410,942, the contents hereby incorporated by reference as if set forth in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to new chemical entities and the incorporation and use of the new chemical entities as fragrance materials.
BACKGROUND OF THE INVENTION
[0003] There is an ongoing need in the fragrance industry to provide new chemicals to give perfumers and other persons with an ability to create new fragrances for perfumes, colognes and personal care products. Those with skill in the art appreciate how differences in the chemical structure of a molecule can result in significant differences in the odor, notes and characteristics of the molecule. These variations and the ongoing need to discover and use new chemicals in the development of new fragrances allow perfumers to apply new compounds in creating new fragrances.
SUMMARY OF THE INVENTION
[0004] The present invention provides novel chemicals, and the use of the chemicals to enhance the fragrance of perfumes, toilet waters, colognes, personal care products and the like. In addition, the present invention is directed to the use of the novel chemicals to modify or enhance the fragrance in perfumes, toilet waters, colognes, personal products and the like.
[0005] More specifically, the present invention is directed to the novel compounds, represented by the general structures of Formula I and Formula II set forth below:
[0000]
[0006] wherein R is a hydrocarbon moiety consisting of 2 to 10 carbon atoms, including cyclopentyl, cyclohexyl, phenyl, benzyl, or phenylethyl. R1 is hydrogen, methyl or ethyl.
[0007] Another embodiment of the invention is a method for enhancing a perfume by incorporating an olfactory acceptable amount of the compounds provided above.
[0008] These and other embodiments of the present invention will be apparent by reading the following specification.
DETAILED DESCRIPTION OF THE INVENTION
[0009] In Formula I and Formula II above, R represents a hydrocarbon cyclic or aromatic chain, preferably of 2 to 10 carbon atoms in length, most preferably, R is a pentyl group. Hydrocarbon, cyclic or aromatic R groups include, but are not limited to the straight alkyl, cyclic, and aromatic chains. Suitable straight hydrocarbon moieties include ethyl, propyl, butyl, cyclopentyl, cyclohexyl, and the like. Suitable branched hydrocarbon moieties include isopropyl, sec-butyl, tert-butyl, 2-ethyl-propyl, and the like. Suitable hydrocarbon moieties containing double and triple bonds include ethene, propene, 1-butene, 2-butene, penta-1-3-diene, hepta-1,3,5-triene, butyne, hex-1-yne and the like. Suitable aromatic moieties include phenyl, benzyl, phenylethyl and the like.
[0010] In Formula II above, R1 represents a hydrogen, a methyl or an ethyl group. Those with skill in the art will recognize that the compound of Formula I of the present invention has a chiral center, thereby providing several isomers of the claimed compound. As used herein the compounds described herein include the isomeric mixtures of the compounds as well as those isomers that may be separated using techniques known to those with skill in the art. Suitable separation techniques include chromatography, particularly gel chromatography.
[0011] The compounds of the present invention may be prepared from the following compounds:
[0000]
[0012] wherein R is understood to have the same meaning as set forth above.
[0013] The preparation and use of the compound of Formula III is discussed in U.S. Pat. No. 4,585,662, the contents of which are incorporated herein by reference. The compound of Formula IV may be prepared from the compound of Formula III by following the Oppenauer oxidation reaction procedure known to persons skilled in the art.
[0014] The compound of Formula I may be prepared from the compound of Formula IV by following the procedure of the Corey cyclopropanation reaction, see Example A below. The compound of Formula II may be prepared from the compound of Formula III by following the procedure of the Simmons-Smith cyclopropanation reaction, see Example B below. The compound of Formula II may also be prepared from the compound of Formula I by following the Red-Al reduction reaction, see Example C below. We have discovered that the compounds have a strong and pleasant fruity note with violet, soft green tones that are well suited for use as a fragrance ingredient.
[0015] The use of the compounds of the present invention is widely applicable in current perfumery products, including the preparation of perfumes and colognes, the perfuming of personal care products such as soaps, shower gels, and hair care products as well as air fresheners and cosmetic preparations. The present invention can also be used to perfume cleaning agents, such as, but not limited to detergents, dishwashing materials, scrubbing compositions, window cleaners and the like.
[0016] In these preparations, the compounds of the present invention can be used alone or in combination with other perfuming compositions, solvents, adjuvants and the like. The nature and variety of the other ingredients that can also be employed are known to those with skill in the art.
[0017] Many types of fragrances can be employed in the present invention, the only limitation being the compatibility with the other components being employed. Suitable fragrances include but are not limited to fruits such as almond, apple, cherry, grape, pear, pineapple, orange, strawberry, raspberry; musk, flower scents such as lavender-like, rose-like, iris-like, carnation-like. Other pleasant scents include herbal and woodland scents derived from pine, spruce and other forest smells. Fragrances may also be derived from various oils, such as essential oils, or from plant materials such as peppermint, spearmint and the like.
[0018] A list of suitable fragrances is provided in U.S. Pat. No. 4,534,891, the contents of which are incorporated by reference as if set forth in its entirety. Another source of suitable fragrances is found in Perfumes, Cosmetics and Soaps , Second Edition, edited by W. A. Poucher, 1959. Among the fragrances provided in this treatise are acacia, cassie, chypre, cyclamen, fern, gardenia, hawthorn, heliotrope, honeysuckle, hyacinth, jasmine, lilac, lily, magnolia, mimosa, narcissus, freshly-cut hay, orange blossom, orchid, reseda, sweet pea, trefle, tuberose, vanilla, violet, wallflower, and the like.
[0019] Olfactory effective amount is understood to mean the amount of compound in perfume compositions the individual component will contribute to its particular olfactory characteristics, but the olfactory effect of the perfume composition will be the sum of the effects of each of the perfumes or fragrance ingredients. Thus the compounds of the invention can be used to alter the aroma characteristics of the perfume composition, or by modifying the olfactory reaction contributed by another ingredient in the composition. The amount will vary depending on many factors including other ingredients, their relative amounts and the effect that is desired.
[0020] The level of compound of the invention employed in the perfumed article varies from about 0.005 to about 10 weight percent, preferably from about 0.5 to about 8 and most preferably from about 1 to about 7 weight percent. In addition to the compounds other agents can be used in conjunction with the fragrance. Well known materials such as surfactants, emulsifiers, polymers to encapsulate the fragrance can also be employed without departing from the scope of the present invention.
[0021] Another method of reporting the level of the compounds of the invention in the perfumed composition, i.e., the compounds as a weight percentage of the materials added to impart the desired fragrance. The compounds of the invention can range widely from 0.005 to about 70 weight percent of the perfumed composition, preferably from about 0.1 to about 50 and most preferably from about 0.2 to about 25 weight percent. Those with skill in the art will be able to employ the desired level of the compounds of the invention to provide the desired fragrance and intensity.
[0022] The following are provided as specific embodiments of the present invention. Other modifications of this invention will be readily apparent to those skilled in the art. Such modifications are understood to be within the scope of this invention. As used herein all percentages are weight percent unless otherwise noted, ppm is understood to stand for parts per million and g is understood to be grams.
EXAMPLE A
Preparation of 1-(2-Ethyl-1-Methyl-Cyclopropyl)-Hexane-1-one
[0023] To a dry 2 liter multi-neck round bottom flask fitted with an air stirrer, nitrogen inlet condenser and an addition funnel under vacuum 1.5 g of 60% NaH and 50 ml of hexane were added. The mixture was stirred, allowed to settle and hexane removed. The above procedure was repeated twice. The pressure was reduced and the vacuum broken under nitrogen. Fifty (50) ml Dimethylsulfoxide (DMSO) and 9 g of 98% (CH 3 ) 3 SOI were slowly added over 90 minutes. Hydrogen gas began to evolve. The mixture was heated to 70° C. until hydrogen stopped evolving. The mixture was cooled to a room temperature and 4-methyl-3-decene-5-one was added dropwise. Upon completion of the addition of 4-methyl-3-decene-5-one, the mixture was stirred for 2 hours at a room temperature and then for 1 hour at 50° C. The mixture was quenched with 80 ml of water and the organic layer extracted with three portions of 25 ml of Et 2 O. The extracts were washed again with three portions of 25 ml of cold water and the organic layer then dried over anhydrous MgSO 4 . The ether was evaporated.
[0024] The NMR spectrum of the 1-(2-ethyl-1-methyl-cyclopropyl)-hexane-1-one is as follows: 0.9 ppm (m, 3H); 1.0 ppm (m, 3H); 1.2-1.4 ppm (m, 7H); 1.5-1.7 ppm (m, 3H); 2.0 ppm (m, 2H); 4.0 ppm (t, 1H); 5.4 ppm (t, 1H).
EXAMPLE B
Preparation of 2-Ethyl-1-Methyl-alpha-Pentyl-Cyclopropanemethanol
[0025] To a dry 2 liter multi-neck round bottom flask fitted with an air stirrer, nitrogen inlet condenser and an addition funnel 8 g of a ZnCu and 75 ml of Methyl Tertiary Butyl Ether (MTBE) was added. The resulting mixture was stirred for 5 minutes. After the temperature of the mixture was stabilized, 24 g of CH 2 I 2 was added over 10 minutes while stirring. After the temperature of the mixture was stabilized, the mixture was heated to reflux. As the temperature of the mixture reached 44° C., 17 g of 4-methyl-3-decene-5-ol was added over 30 minutes. After the addition of 4-methyl-3-decene-5-ol, a first sample was taken. Additional samples were taken every hour for three hours. Then the sample was quenched with saturated NH 4 Cl, aqueous layer separated and the organic layer filtered through celite.
[0000] The gas chromatography test indicated that 96.93% of the original alcohol converted to the cyclopropanated alcohol.
[0026] The NMR spectrum of the 2-ethyl-1-methyl-alpha-pentyl-cyclopropanemethanol is as follows: 0.0 ppm (m, 1H); 0.5 ppm (m, 2H); 0.88 ppm (d, 3H); 1.0 ppm (m, 6H); 1.2-1.4 ppm (m, 9H); 1.48 ppm (m, 1H); 2.75 ppm (m, 1H).
EXAMPLE C
Preparation of 2-Ethyl-1-Methyl-alpha-pentyl-Cyclopropanemethanol from 1-(2-Ethyl-1-Methyl-Cyclopropyl)-Hexane-1-one
[0027] Approximately 1 g of 1-(2-ethyl-1-methyl-cyclopropyl)-hexane-1-one was added by a pipette into a 13 mm by 100 mm test tube. Red-Al (30% solution in toluene) was added dropwise with shaking until no heat was given off. The mixture was quenched by adding 5% Na 2 CO 3 until foaming stopped. The mixture was shaken and the organic layer was separated. The organic layer was washed with 5 ml of brine. The resulting organic layer was poured onto a watch glass and the solvent was evaporated.
[0028] The NMR spectrum of the 2-ethyl-1-methyl-alpha-pentyl-cyclopropanemethanol is as follows: 0.0 ppm (m, 1H); 0.5 ppm (m, 2H); 0.88 ppm (d, 3H); 1.0 ppm (m, 6H); 1.2-1.4 ppm (m, 9H); 1.48 ppm (m, 1H); 2.75 ppm (m, 1H).
EXAMPLE D
Preparation of 2-Ethyl-Alpha 1-Dimethyl-Alpha-Pentyl Cyclopropanemethanol
[0029] To a dry 5 liter multi-neck round bottom flask fitted with an air stirrer, nitrogen inlet condenser and an addition funnel 1,617 g of CH 3 Li was added and stirred. Three hundred and thirty six (336) g of 1-(2-ethyl-1-methyl-cyclopropyl)-1-hexanone (see Example A for the preparation of 1-(2-ethyl-1-methyl-cyclopropyl)-1-hexanone) was added dropwise over 105 minutes. The temperature of the reaction rose to 63° C. The reaction mixture was aged for 150 minutes and a first sample was taken at 37° C. A second sample was taken at 30° C. after 30 minutes. The mixture was quenched with acetic acid, allowed to settle and layers separated. The aqueous layer was washed twice with 100 ml of toluene. The toluene extracts were added to the organic layer and washed with Na 2 CO 3 .
[0030] The NMR spectrum of the 2-ethyl-alpha,1-dimethyl-alpha-pentyl cyclopropanemethanol is as follows: −0.18 ppm (d, 1H); −0.25 ppm (d, 1H); 0.65 ppm (m, 1H); 1.1 ppm (s, 3H); 1.18 ppm (s, 3H); 1.55 ppm (m, 2H); 1.25-1.5 ppm (m, 8H). | The present invention is directed to novel ketone and alcohol compounds and the use of these novel compounds in creating fragrances and scents in items such as perfumes, colognes and personal care products. | 2 |
BACKGROUND OF THE INVENTION
1. Technical Field
This application relates to comparative analysis. In particular, this application relates to rating services and capabilities delivered by a company to its customers.
2. Related Art
The growing global economy has contributed to increased competition in almost every aspect of the marketplace. With the rise in competition, companies seek increasingly reliable and informative comparisons with its competitors in order to differentiate themselves from the competition and attract business. However, providing such comparisons is a difficult endeavor.
Within and across industries, companies offer a multitude of services and capabilities to their customers. Simple consideration of which company offers more or less services and capabilities may not provide a company with enough useful information to determine where it can improve, or where it stands out above the competition. Furthermore, some services may be of greater value to the customer than others, and many other intricate evaluation details, such as how to score capabilities, influence how to provide a meaningful comparison.
Therefore, a need exists to address the problems noted above and others previously experienced.
SUMMARY
A capability assessment system provides a company-tailored evaluation with clear distinction between progressive companies and companies that offer only basic services. The system applies a flexible and effective rating and point mapping approach to a list of capabilities that may or may not be utilized by the company. The point mapping approach may include a non-linear scoring sequence and an adaptable score tuning gap within the scoring sequence. The adaptable score tuning gap may facilitate clear delineation between the average and above average companies, as well as which capabilities, if utilized, can put a company ahead of the competition.
Based on the rating and point mapping approach, a company is scored according to which capabilities are applicable to the company, and which of the applicable capabilities it actually utilized. With the final score(s), a company can efficiently prioritize and identify which improvements to its rendered services will have the greater overall impact, benefiting both customer and the company itself.
The system effectively provides objective, consistent, and detailed scoring and information about a company's practices. In addition, the system provides a clear distinction between progressive companies and companies that offer only basic services, and identifies which services set the progressive companies above the competition and/or which services a company may utilize to catch up to or surpass its competition. Accordingly, the system allows the company to effectively recognize, meet, and exceeding customer expectations.
Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. All such additional systems, methods, features and advantages are included within this description, are within the scope of the invention, and are protected by the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The system may be better understood with reference to the following drawings and description. The elements in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the type model. In the figures, like-referenced numerals designate corresponding features throughout the different views.
FIG. 1 shows a portion of a master capability table.
FIG. 2 shows a portion of an assessment template.
FIG. 3 shows a non-linear point mapping.
FIG. 4 shows a flow diagram for client capability table generating logic.
FIG. 5 shows a client capability table.
FIG. 6 shows a flow diagram for score determining logic.
FIG. 7 shows a client rating scale.
FIG. 8 shows a capability assessment system.
FIG. 9 shows a final assessment report.
FIG. 10 shows an exemplary client comparison report.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a portion of a master capability table 100 (“table 100 ”). The master capability table 100 includes touchpoints 102 , channels 104 , and capabilities 106 . The master capability table 100 may also include a rating 108 associated with each capability 106 .
A touchpoint refers to a category of service that may be rendered by a client. For example, the table 100 identifies seven touchpoints (services), including 1) Discover Service, 2) Sign-Up for Service, 3) Activate Service, 4) Use Service, 5) Pay for Service, 6) Resolve Issue, and 7) Terminate Service.
The “Discover Service” touchpoint relates to services that aid customers in learning about services and products offered by the client. The “Sign-Up for Service” touchpoint relates to ordering desired products and services by the customer. The “Activate Service” touchpoint relates to the installation and/or activation of products and services for the customer. The “Use Service” touchpoint relates to the customer's interaction with the purchased products and services. The “Pay for Service” touchpoint relates to billing and receipt of payment for services rendered. The “Resolve Issue” touchpoint relates to addressing and resolving product and service issues that may arise. The “Terminate Service” touchpoint relates to the deactivation of services and/or termination of a client/customer relationship.
A channel 104 may refer to the interaction between the client and its customers. The table 100 includes the channels of Assisted, Self-Service, or Face to Face. An Assisted channel may include remote modes of communication that involve more direct client/customer interaction, such as calls center or other. The Self-Service channel may relate to, for example, online, IVR, mobile, or other remote modes of communication that may or may not involve direct or real-time client/customer interaction. The “Face to Face” channel may involve face to face client/customer interaction, such as due to a customer visit to a store/branch or a field service visit.
A capability 106 refers to a service that may be provided by the client to the customer. For example, the capabilities may refer to the client's agents and whether different agents handle different products 110 or whether the agents are able to walk the customer through the available products 112 . Each capability may be assigned to or otherwise correspond to an appropriate touchpoint and channel. The capability may correspond to a touchpoint according to the characteristics of the capability in relation to the characteristics of the touchpoints and channels. For example, the capability 114 , which refers to whether the client provides different phone numbers for different products, relates to customer call-in events. Accordingly, the capability may correspond to the “Assisted” channel and “Sign-up for Service” touchpoint.
Additional, fewer, or different touchpoints, channels, and capabilities may be defined. For example, Tables 1 and 2 below each show portions of exemplary master capability lists that include different sets of capabilities, channels, and touchpoints. The types and/or descriptions of the capabilities, channels, and touchpoints may be tailored to the application in which the comparative landscape tool is used. Table 1 is a portion of a master capability list that may be used in a comparative landscape tool that assesses the overall customer experience provided by the client. Table 2 is a portion of a master capability list that may be used in a comparative landscape tool that assesses the customer service and support provided by the client.
The table 100 also associates a rating 108 with each capability 106 . The table 100 uses a four-leveled rating system including, in order from lowest rating to highest rating, Basic, Parity, Competitive, and Differentiated. The ratings 108 may refer to the importance or value of a capability. A Basic rating may correspond to, for example, a rudimentary level of service rendered by a company. A Parity rating may correspond to an average service rendered by a company. A Competitive rating may correspond to an above average service rendered by a company. A Differentiated rating may correspond to a service that stands out within, or sets apart the company from, the industry. Accordingly, a differentiated capability may be scored higher than a basic capability. The capability assessment system described below may determine which capabilities apply to an industry, determine which of those applicable capabilities are utilized by a particular company within that industry, and then score the company based on the rating 108 associated with each applicable capability.
FIG. 2 shows a portion of an assessment table 200 . The assessment table includes a list of capabilities 202 , along with the touchpoints 204 and channels 206 associated with each capability 202 . The “Applicable” column 208 identifies which capabilities 202 are applicable to the client or the client's industry. An identifier, such as a ‘Y’ for ‘Yes’ or ‘N’ for ‘No’, may be applied to each row in the “Applicable” column 208 to identify whether the corresponding capability 202 is applicable.
The configuration of the “Applicable” column 208 to a client may be industry or client specific. An assessor may configure the “Applicable” column on a client-by-client basis. As an alternative, an assessor may determine default sets of capabilities that are applicable to different specific industries, where the “Applicable” column 208 may be substantially similar for each client within a specific industry. In this example, an assessor may, as part of a preprocessing step, identify which capabilities apply to each industry. When a specific client is identified with an industry, the set of default capabilities for that industry may be applied to the “Applicable” column 208 for that client.
The “Utilized” column 210 identifies which capabilities are actually performed by the specific client with capability implementation specifiers. An assessor determines which capabilities are utilized and applies the appropriate identifiers in the “Utilized” column 210 . A capability identified by, for example, a ‘No’ in the “Applicable” column 208 is a capability that is not applicable to that client. In some applications, whether an inapplicable capability is utilized by the client may not be relevant. Accordingly, for each capability identified as not being applicable to the client, the assessment table 200 may be configured to grey out, lock, hide, or otherwise prevent alteration to a row corresponding to an inapplicable capability. The assessment table 200 may be implemented in a spreadsheet, such as Excel®, in a programmable database, or other programmable system.
The “Verified” column 212 may identify which capabilities should be subject to further verification. For example, if it is not clear whether a capability is utilized by the client, the assessor may “check” or otherwise mark the “Verified” column's row that corresponds to that capability. The mark may indicate that further verification or investigation of the client and/or that capability should be conducted.
FIG. 3 shows a point mapping 300 . The point mapping 300 includes four capability rating levels: Basic 302 , Parity 304 , Competitive 306 , and Differentiated 308 . The point mapping associates a capability level score with each capability rating level. The point mapping 300 in FIG. 3 is a non-linear point mapping characterized with a non-linear progression of scores between capability rating levels. The scores shown in FIG. 3 progress between ratings as follows: 1, 2, 4, 5. Rather than increasing linearly from every rating to the next, the point mapping 300 includes the non-linear jump from 2 to 4 between adjacent ratings Parity and Competitive. A tuning gap 310 of one point is present between Basic and Parity level, a tuning gap 312 of two points is present between Parity and Competitive level, and a tuning gap 314 of one point is present between Competitive and Differentiated level. Each tuning gap 310 - 314 may be independently adjusted to tailor the point mapping 300 for application to any particular industry or application. The tuning gaps are not limited to integers.
Other point mapping approaches may be used and adapted to specific applications. The non-linear progression of scores from Basic to Differentiated may be configured or customized to any application to give helpful and meaningful results. For example, a non-linear progression of capability scores may weight or further set apart certain capability rating levels. As noted above, the non-linear progression of scores may be adapted by modifying the tuning gaps 310 - 314 . The adaptable score tuning gaps facilitate differentiation of companies that utilize Competitive or Differentiated capabilities to set themselves apart from those that utilize Basic or Parity capabilities. The capability level score may be configured for different applications, different industries, or according to other factors.
FIG. 4 shows a flow diagram 400 for client capability table generating logic. The client capability table generating logic obtains a client assessment report ( 402 ). The client assessment report may be generated by an assessor that determines whether capabilities that are applicable to the client, or to the client's industry, are implemented by that client. Alternatively, the client may submit answers to queries manually or automatically, such as through a web portal into the system, that define the client assessment report. The client assessment report may include capability implementation identifiers, such as a “Yes” or “No”, that identifies whether an applicable capability is implemented or utilized by the client. The capability assessment report may be input in a spreadsheet, such as an Excel® spreadsheet or Lotus® spreadsheet. The client capability table generating logic described below may store the client assessment report in a memory.
The client capability table generating logic may determine an applicable to point mapping for the client assessment report ( 404 ). The applicable point mapping, such as the point mapping 300 shown in FIG. 3 , may include a capability rating level and capability level scores associated with each capability rating level. The applicable point mapping may be determined on a client by client, or industry by industry basis, and/or based on other factors. For example, the same, or a substantially similar, point mapping may apply to clients within a certain industry. The client capability table generating logic may identify the relevant industry associated with a particular client. The assessor that generates the client assessment report may alternatively identify the relevant industry.
The client capability table generating logic may build a client capability table ( 406 ). The client capability table may include capability implementation specifiers, capability IDs for the capability implementation specifiers, and point assignments retrieved from the applicable point mapping for the capability IDs. The capability implementation specifiers may be numerical or other values that specifiers whether a capability is utilized by the client. The capability IDs may be unique IDs associated with each of the capabilities. The unique IDs may include a numerical, alphanumeric, or other format. The point assignments may include the capability level scores identified in the applicable point mapping.
FIG. 5 shows a client capability table 500 . The client capability table 500 includes capability implementation specifiers 502 , capability IDs 504 for the capability implementation specifiers 502 , and point assignments 506 retrieved from the applicable point mapping for the capability IDs. In FIG. 5 , the capability implementation specifiers 502 associate a ‘1’ for capabilities that are utilized by the client and a ‘0’ for capabilities that are not utilized by the client. The point assignments 506 shown in FIG. 5 correspond to the point mapping shown in FIG. 3 in which a capability level score of 1, 2, 4, and 5 correspond to the capability rating levels 508 of Basic, Parity, Competitive, and Differentiated, respectively.
The client capability table 500 may also include the capability rating levels 508 associated with each capability, as well as a touchpoint identifier 510 and a channel identifier 512 associated with each capability. The touchpoint identifiers 510 and channel identifiers 512 may include an identification of the touchpoint and channel, respectively, associated with each capability. The touchpoint identifiers 510 and channel identifiers 512 are identified with text in the client capability table 500 . The client capability table 500 may alternatively include other identifiers, such as unique numerical IDs associated with each touchpoint and channel.
FIG. 6 shows a flow diagram 600 for score determining logic. The score determining logic may determine a total applicable capability metric ( 602 ). The total applicable capability metric may include the total number of applicable capabilities across an identified capability group. The identified capability group may include all touchpoints, a single touchpoint, a single channel, a combination of touchpoints or channels, a specific channel within a touchpoint, and/or other groupings of applicable capabilities. For example, the client capability table 500 may correspond to an identified capability group including capabilities within the “Discover Service” touchpoint and “Assisted” channel. Accordingly, the score determining logic may determine that the total applicable capability metric corresponding the client capability table 500 is ten (10), which equals the total number of applicable capabilities with the identified capability group (i.e., with the “Discover Service” touchpoint and “Assisted” channel). FIG. 6 is further discussed with reference to the client capability table 500 . However, the client capability table 500 is an example only and may vary according to the client, industry, application, identified capability group, and/or other factors.
The score determining logic selects an applicable capability from the identified capability group ( 604 ). The applicable capability may be selected from a client capability table 500 generated by client capability table generating logic. The selected applicable capability may be identified according to the capability identifier 504 .
The score determining logic looks up a capability level score associated with the selected applicable capability ( 606 ). The score determining logic may look up the capability level score from the client capability table. For example, if the selected applicable capability corresponds to the capability identifier 243 in FIG. 5 , the scored determining logic may look up or otherwise retrieve the corresponding capability level score of 1.000. The score determining logic determines whether the selected applicable capability is utilized by the client ( 608 ). The score determining logic may look up the capability implementation specifier 502 from the client capability table 500 that corresponds to the selected applicable capability. The looked up capability implementation specifier 502 indicates whether the corresponding applicable capability is utilized by the client. For example, if the selected applicable capability corresponds to the capability identifier 243 , the score determining logic may retrieve the corresponding capability implementation specifier as a ‘1’, indicating that the selected applicable capability is utilized by the client.
If the selected applicable capability is not utilized by the client, the score determining logic determines whether there are more applicable capabilities from the identified capability group to be examined ( 610 ). If the selected applicable capability is utilized by the client, the score determining logic adds the capability level score (obtained at block 606 ) to a running total of a total assessment score ( 612 ). The total assessment score may represent a running total of the summed capability level scores associated with each applicable capability that is utilized by the client. According to block 608 , a capability level score associated with a non-utilized capability may not be added to the total assessment score.
The score determining logic determines whether there are more applicable capabilities from the identified capability group to be examined ( 610 ). If there are more applicable capabilities to be examined, the score determining logic selects a next applicable capability ( 614 ) and repeats the instructions of blocks 606 - 612 . According to blocks 606 - 612 , the score determining logic adds the capability level score associated with each utilized capability to the running total of the total assessment score ( 612 ). The client capability table 500 indicates that six (6) out of the ten (10) applicable capabilities are utilized. The score determining logic adds the capability level scores 506 associated with the utilized capabilities to the total assessment score.
With respect to the client capability table 500 , the score determining logic will generate a total assessment score of fifteen (15). The capabilities 512 - 522 correspond to utilized capabilities. In particular, two capabilities 512 and 514 have a capability level score of ‘1’; two capabilities 516 and 518 have a capability level score of ‘2’; on capability 520 has a capability level score of ‘4’; and one capability 522 has a capability level score of ‘5’. Accordingly, the total assessment score may be determined as 2×1+2×2+1×4+1×5=15.
If there are no remaining applicable capabilities to be examined, the score determining logic generates a final assessment score ( 616 ). The final assessment score may be a numerical score that provides a useful client rating across the identified capability group. The final assessment score may be obtained based on the total assessment score by the total applicable capability metric. For example, the score determining logic may generate the final assessment score by dividing the total assessment score by the total applicable capability metric. With respect to the client capability table 500 , the final assessment score may be 1.5, which equals the total assessment score (15) divided by the total applicable capability metric (10).
The score determining logic may determine a final assessment rating ( 618 ). Based on the final assessment score, the score determining logic may assign the final assessment rating to the client. The score determining logic may compare the final assessment score with a client rating scale to determine the final assessment rating. The client rating scale may include a numerical range associated with each possible rating (e.g., Basic, Parity, Competitive, and Differentiated). The score determining logic may assign the final assessment rating according which numerical range the final assessment score falls within. For example, client rating scale may associate a final assessment score of between 0-1.8 to a Basic rating. In this example, the score determining logic would determine a final assessment rating of “Basic” based on the final assessment score of 1.5.
The final assessment rating may correspond to the identified capability group. If the identified capability group includes capabilities across all touchpoints, the final assessment rating will apply to the client's rating across all touchpoints. Similarly, if the identified capability group includes capabilities across a specific channel, the final assessment rating will apply to the client's rating across that channel. The identified capability group corresponding to the client capability table 500 shown in FIG. 5 included capabilities within the “Discover Service” touchpoint and “Assisted” channel. Accordingly, the final assessment score of 1.5 and final assessment rating of “Basic” correspond to the client's capabilities within the “Discover Service” touchpoint and “Assisted” channel. A client may be interested in ratings across multiple capability groups. The score determining logic may determine, according to the flow diagram 600 , final assessment scores and ratings for multiple client capability groups.
FIG. 7 shows a client rating scale 700 . The client rating scale 700 includes numerical ranges associated with a final assessment rating. Score to determining logic may compare a final assessment score to the numerical ranges to obtain a final assessment rating for the client. For example, the numerical ranges may be different for different industries, or based on other relevant factors. In addition, the value of certain capabilities may evolve over time. For example, a capability that was once valued highly with a “Differentiated” rating, may have decreased in importance some number of years later. As capabilities evolve, the corresponding capability level score, as well as the numerical ranges of the client rating scale may change accordingly.
FIG. 8 shows a capability assessment system (“system”) 800 . The system 800 includes a processor 802 , a memory 804 , and assessment database 806 . The memory 804 holds client capability table generating logic 808 and score determining logic 810 that assist in evaluating the services and capabilities delivered by the client to its customers.
The assessment database 806 holds one or more master capability structures 812 . A master capability structure includes a comprehensive list of the capabilities that may apply to a particular industry or client. As discussed below, the client capability table generating logic 808 may use a master capability structure to generate a client capability table. The assessment database 806 may hold multiple master capability structures 812 for different service delivery applications. For example, Tables 1 and 2 show two exemplary master capability lists. Table 1 shows a master capability list for a “Customer Experience” service delivery application. Table 2 shows a master capability list for a “Customer Service & Support” service delivery application. Each master capability list may include a description of the capability, an identification of the touchpoint and channel associated with each capability, and the rating associated with each capability.
The assessment database 806 may also hold industry specific master capability structures 814 and client specific master capability structures 822 . The industry specific master capability structures 814 may include, by way of example, an automotive industry master capability structure 816 , an aviation industry master capability structure 818 , a clothing industry master capability structure 820 , and other master capability structures adapted to other specific industries. The client specific master capability structures 822 may include master capability structures 824 - 828 for client X, client Y, client Z, or for other specific clients.
The system 100 , or an assessor using the system 100 , may determine which capabilities of the master capability structure 814 are applicable to a specific industry or client. Accordingly, the industry specific master capability structures 814 may include capabilities that are applicable to that specific industry. The client specific master capability structures 822 may include those capabilities from the master capability structure 812 that are applicable to the specific client. A capability may be applicable to a specific industry or client if they are relevant to the client or industry. For example, the master capability structure 812 may include capabilities that are relevant to the aviation industry, but that are not relevant to the clothing industry, and visa versa. Determining which capabilities are applicable to specific industries or clients avoids penalizing a client for not utilizing a capability that is not relevant to its business.
The assessment database 806 may hold one or more point mappings 830 and one or more client rating scales 832 . The point mapping 830 provides the capability level score associated with each capability rating level. FIG. 3 shows an exemplary point mapping 300 . The point mapping 830 may include integer, decimal, or other numerical scores associated with each capability. The client rating scale 832 includes numerical ranges associated with each capability rating level. FIG. 7 shows an exemplary client rating scale 700 . The assessment database 806 may include multiple industry and/or client specific point mappings 834 .
The client capability table generating logic 808 may include instructions that cause the processor 802 to obtain a client assessment report as detailed above with respect to FIG. 4 . The memory 804 may store the obtained client assessment report 834 . FIG. 1 shows an exemplary client assessment report. The client assessment report 834 may be generated or completed by an assessor. The assessor determines whether capabilities applicable to the client are utilized by that client.
The client assessment report 834 may include capability implementation identifiers 836 and capability applicability identifiers 838 . The client assessment report 834 may also include capability identifiers 840 , touchpoint identifiers 842 , and channel identifiers 844 . The capability implementation identifiers 836 identify which capabilities are utilized by the client. The capability applicability identifiers 838 identify which capabilities are applicable to the client. The capability identifiers 840 may include a name and/or description of each capability. The touchpoint and channel identifiers 842 and 844 may include a name and/or description of each touchpoint and/or channel, respectively, associated with each capability.
The client capability table generating logic 808 determines an applicable point mapping 846 for the client assessment report 834 as detailed above with respect to FIG. 4 . The client capability table generating logic 808 may select and retrieve the applicable point mapping 846 from among the point mappings 830 stored in the assessment database 806 . As indicated above, the point mapping 830 may include industry and/or client specific point mappings. Based on an identification of the client or the client's industry, the client capability table generating logic 808 may identify and retrieve from the assessment database 806 the applicable point mapping 846 . The applicable point mapping 846 , such as the point mapping 300 shown in FIG. 3 , may include capability rating levels and capability level scores associated with each capability rating level. The memory 804 may store the applicable point mapping 846 .
When an assessor completes the client assessment report 834 , the assessor may load the assessment report to the assessment database 806 , a sharepoint site, or other location. The client capability table generating logic 808 may move the assessment report 834 to the memory 804 and generate a client capability table 848 . If the client assessment report 834 is an Excel® file, for example, the client capability table generating logic 808 may initiate a Microsoft ETL package to load the client assessment report 834 into the memory 804 and execute a store procedure to validate the data and build the client capability table 848 for the specific client assessment. The memory 804 may store the client capability table 848 . The store procedure may be a part of the client capability table generating logic 808 , or a separate SQL program residing in the memory 804 . The store procedure may call another store procedure that triggers the score determining logic 810 .
The client capability table 848 includes capability implementation specifiers 850 , capability IDs 852 for the capability implementation specifiers 850 , and point assignments 854 retrieved from the applicable point mapping 846 for the capability IDs 852 . The client capability table 848 may also include capability rating levels 856 associated with each capability. An exemplary client capability table 848 is discussed in more detail above and shown in FIG. 5 .
The score determining logic 810 determines a total applicable capability metric 858 as detailed above with respect to FIG. 6 . The total applicable capability metric 858 metric may include the total number of applicable capabilities across an identified capability group 860 . The identified capability group 860 may include all touchpoints, a single touchpoint, a single channel, a combination of touchpoints or channels, a specific channel within a touchpoint, and/or other groupings of applicable capabilities. The memory 804 may store the total applicable capability metric 858 and the identified capability group 860 .
The memory 804 may store a total assessment score 862 , a final assessment score 864 , and a final assessment rating 866 . The score determining logic 810 may look up the point assignment 854 associated with each utilized capability. The score determining logic 810 may use the capability implementation specifiers 850 to identify which of the applicable capabilities are utilized by the client. The total assessment score 862 may equal the sum of the point assignments 854 associated with each utilized capability. The score determining logic 810 determines the final assessment score 868 based on the total applicable capability metric 858 and the final assessment score 864 . For example, the final assessment score 864 may equal the total assessment score 862 divided by the total applicable capability metric 858 .
Based on the final assessment score 864 , the score determining logic 810 may determine the final assessment rating 866 . The score determining logic 810 may compare the final assessment score 864 with an applicable client rating scale 868 to determine the final assessment rating 866 . The applicable client rating scale 868 may include a numerical range associated with each possible rating (e.g., Basic, Parity, Competitive, and Differentiated). The score determining logic 810 may assign the final assessment rating 866 according which numerical range the final assessment score 864 falls within. The score determining logic 810 may select and retrieve the applicable client rating scale 868 from among the client rating scales 832 stored in the assessment database 806 . As indicated above, the client rating scale may include industry and/or client specific client rating scales. Based on an indication of the client or the client's industry, the score determining logic 810 may identify and retrieve from the assessment database 806 the applicable client rating scale 868 . Based on the applicable client rating scale 868 and the final assessment score 864 , the score determining logic determines the final assessment rating 866 .
The system 800 may determine a final assessment score 864 and/or final assessment rating 866 across multiple identified capability groups. For example, the system 800 may determine final assessment scores 864 and ratings 866 for each is individual touchpoint or channel. The system 800 may additionally or alternatively store the final assessment scores 864 and ratings 866 in a client score repository 870 in the assessment database 806 . The client score repository 870 may include the final assessment scores 864 and ratings 866 for multiple clients that have used the system 800 .
The memory 804 may include report generating logic 872 . The report generating logic 872 may generate and display a variety of final assessment reports 874 for the client based on the final assessment score 866 and the final assessment rating 868 . FIGS. 9-12 show exemplary final assessment reports 874 that may be generated by the report generating logic 872 . The memory 804 may store the final assessment reports 874 . The system 800 may interact with the client and/or assessor using a display 876 .
The final assessment reports 874 may include a comparison of the client's final assessment scores 864 and ratings 866 to the final assessment scores and ratings stored in the client score repository 870 for other clients that have used the system 800 . The comparison assists the client in comparing its practices to the practices of other companies to determine where it distinguishes itself from, or lags behind, its competition.
Exemplary aspects, features, and components of the system are described above. However, the system may be implemented in many different ways. For example, although some features are shown stored in computer-readable memories (e.g., as logic implemented as computer-executable instructions or as data structures in memory), all or part of the system and its logic and data structures may be stored on, distributed across, or read from other machine-readable media. The media may include hard disks, floppy disks, CD-ROMs, a signal, such as a signal received from a network or received over multiple packets communicated across the network.
The system may be implemented with additional, different, or fewer components. As one example, a processor may be implemented as a microprocessor, a microcontroller, a DSP, an application specific integrated circuit (ASIC), discrete logic, or a combination of other types of circuits or logic. As another example, memories may be DRAM, SRAM, Flash or any other type of memory. The processing capability of the system may be distributed among multiple components, such as among multiple processors and memories, optionally including multiple distributed processing systems. Parameters, databases, and other data structures may be separately stored and managed, may be incorporated into a single memory or database, may be logically and physically organized in many different ways, and may implemented with different types of data structures such as linked lists, hash tables, or implicit storage mechanisms. Logic, such as programs or circuitry, may be combined or split among multiple programs, distributed across several memories and processors, and may be implemented in a library, such as a shared library (e.g., a dynamic link library (DLL)). The DLL, for example, may store code that prepares intermediate mappings or implements a search on the mappings. As another example, the DLL may itself provide all or some of the functionality of the system, tool, or both.
FIGS. 9-10 show final assessment reports that may be generated by the report generating logic. In particular, FIG. 9 shows an exemplary client capability summary 900 (“summary 900 ”). The summary 900 shows the number of applicable capabilities 902 , utilized capabilities 904 , and “not utilized” capabilities 906 for each touchpoint 908 , as well as overall data 910 across all touchpoints. The summary 900 also shows a final assessment score 912 for each touchpoint, including an overall score. As discussed above with respect to FIG. 8 , a capability assessment system may use the final assessment scores 912 to determine a final assessment rating for each touchpoint and/or across all touchpoints. A similar report may be generated to show final assessment scores for each channel.
FIG. 10 shows an exemplary client comparison report 1000 (“report 1000 ”). The report 1000 ranks several clients for which final assessment scores and ratings have been determined into quartiles. The report 1000 may be configured to rank the clients into more or less than four groups. Reports similar to the report 1000 may be generated for each touchpoint and/or channel. For example, a client comparison report for the touchpoint “Sign-up for Service” may be generated that ranks the clients based on their respective scores for the “Sign-up for Service” touchpoint. Such reports effectively inform each client where they differentiate themselves from, or lag behind, other like companies, allowing companies to more precisely prioritize and identify which improvements to its rendered services will have the greater overall impact. Reports may also be generated that compare the several clients on a capability by capability basis, or that chart or graph each client's scores in relation to each other.
The companies with which a client may be compared in the report 1000 , or other like reports, may be determined on an outside-view or inside-view basis. With the outside-view approach, companies may be grouped based on the customer's perspective. With the inside-view approach, companies may be grouped based on the client perspective, such as through comparison with their peers within the same industry. In the outside-view approach, the client may be compared to companies in other industries as well.
For example, a cable company may be compared to other cable companies under the inside-view approach. In the outside-view approach, the cable company may be compared to, in addition to other cable companies, service providers that service the same or substantially similar customer base and offers similar types of services, such as telephone service providers, internet providers, utilities companies, electronics merchandise providers, and/or other service providers selected based on the described outside-view approach. The outside-view approach may assist a client to be better in tune with customer expectations and learn successful techniques from other companies it may not typically identify with. In addition, conducting the assessment from the customer's perspective (the outside-view approach) may allow the client to effectively differentiate itself from peers and be better in tune with customer expectations and learn successful techniques from other companies it may not typically identify with.
Tables 1 and 2 below show portions of exemplary master capability lists. Table 1 is a portion of a master capability list that may be used in a comparative landscape tool that assesses the overall customer experience provided by the client. Table 2 is a portion of a master capability list that may be used in a comparative landscape tool that assesses the customer service and support provided by the client. The master capability list may be dynamic lists. The ratings may be updated or modified. Capabilities, channels, and/or touchpoints may be added, modified, or removed. These and/or other changes may be a result of industry changes or trends, client/industry preferences, system updates, or other influences.
TABLE 1
Touchpoint
Rating
Channel
Capability
1. Discover
Basic
Assisted
agents: different agents handle different products
Service
(e.g.: cable, home phone, wireless)
2. Sign-Up for
Basic
Assisted
phone numbers: different for different products
Service
6. Resolve
Parity
Assisted
IVR: voice recognition capability
Issues
1. Discover
Parity
Assisted
IVR: friendly voice
Service
3. Activate
Differentiated
Assisted
agents: friendly, helpful, accommodating &
Service
understands the customer. Demonstrate 7 customer
experience dimensions: acknowledgment, efficiency,
knowledgeable, control, choice, commitment, &
consistency.
4. Use
Differentiated
Assisted
agents: friendly, helpful, accommodating &
Service
understands the customer. Demonstrate 7 customer
experience dimensions: acknowledgment, efficiency,
knowledgeable, control, choice, commitment, &
consistency.
2. Sign-Up for
Parity
Face to
Allow customers to sign-up: via authorized dealers
Service
Face
(products/services dependent)
3. Activate
Parity
Face to
field reps: set-up fee is not charged for technician
Service
Face
visits
4. Use
Parity
Face to
industry-specific: tree trimming crews trim trees
Service
Face
away from power lines
5. Pay For
Basic
Assisted
agents: different products (e.g.: cable, home phone,
Service
wireless) are handled by different agents
5. Pay For
Competitive
Self-
payment (channel): at stores using automated
Service
Service
payment kiosks (or similar machines)
6. Resolve
Differentiated
Face to
service appointment window: 2-2.5 hrs
Issues
Face
7. Terminate
Basic
Assisted
cancellations: require live agents
Service
7. Terminate
Basic
Face to
cancellations: For security reasons customers are
Service
Face
required to call in order to cancel their account.
Accounts will be closed shortly after customers'
requests.
TABLE 2
Touchpoint
Rating
Channel
Capability
service strategy:
Basic
back-
Limited or no access to customer data
Customer Segmentation
office
for conducting segmentation analysis
Analysis
service strategy: Industry
Parity
back-
Analysis results not well integrated with
Trends & Competitor
office
overall service business planning
Analysis
service strategy:
Differentiated
back-
Explicit statement of strategy to offer or
Professional Services
office
not offer services beyond the product
Strategy
platforms sold by the company.
service offering
Basic
back-
Manufacturing targeted at minimizing
development: Warranty
office
unit production cost with no view on
Design & Integration
total cost of ownership.
services marketing:
Parity
back-
Marketing objectives and strategies are
Marketing Objectives &
office
not aligned with overall service business
Strategy
plan.
services marketing:
Differentiated
assisted &
Online and offline marketing efforts are
Marketing Objectives &
face-to-
integrated.
Strategy
face
services marketing:
Differentiated
back-
The measurement system balances
Service Portfolio Analysis
office
short-term objectives with long-term
goals, financial metrics with nonfinancial
metrics, and external performance
(customer satisfaction) with internal
business process performance.
service selling: Customer
Basic
back-
Inconsistent contract creation and
Contract Negotiation &
office
management process
Creation
services selling: Customer
Parity
assisted &
Paper forms are used for contracts
Contract Negotiation &
face-to-
Creation
face
services selling: Customer
Parity
self-
Remote users can not edit contracts data
Contract Negotiation &
service
bases
Creation
services selling: Sales
Basic
assisted &
Little to no channel sales support.
Execution
face-to-
face
services event management:
Basic
back-
Processed manually through company
Email
office
email system (Outlook, etc.); no email
management system in place.
service event management:
Basic
back-
Dispatching, route determination, and
Scheduling & Dispatch
office
service area rules either do not exist or
are informal.
service event management:
Basic
self-
Internet interactions are limited to
Web/esupport
service
electronic service sales literature (e.g.
service contact information, service
locations, hours of operation, etc.)
installation, maintenance &
Basic
assisted &
Majority of repairs are carried out
repair: field repair
face-to-
without any pre-diagnosis.
face
installation, maintenance &
Basic
assisted &
Adjustments and rework % is high.
repair: installation
face-to-
management
face
installation, maintenance &
Basic
back-
OEM supplied embedded technology is
repair: predictive
office
not fully leveraged.
maintenance
service parts & logistics
Differentiated
back-
Automatic notification of excess/obsolete
management: inventory
office
inventory.
replenishment
service parts & logistics
Basic
back-
Does not address reverse
management: returns
office
logistics/returns.
professional services: prof
Basic
back-
Hardware leads the sale.
svc sales & delivery
office
partner relationship
Parity
back-
Data shared between organizations is
management: partner
office
not automated.
relationship mgt
customer account
Basic
back-
All validations are performed manually;
management: contract
office
reviewers ensure that rules and
management
standards have been followed by the
preparers.
customer account
Parity
back-
Billing does not promote a steady
management: customer
office
revenue stream
billing
product lifecycle
Basic
back-
Defects are not tracked
management: defect
office
tracking
human performance/
Basic
back-
Compensation system is not tied to
knowledge management:
office
performance.
career path/
compensation
human performance/
Parity
back-
A myriad of inconsistent performance
knowledge management:
office
metrics analyzed infrequently.
performance management
human performance/
Competitive
back-
Formal training curriculums and
knowledge management:
office
programs are provided, utilized, and
training management
tracked for compliance.
While various 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 within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. | A capability assessment system provides a tailored evaluation with clear distinction between progressive companies and companies that offer more basic services. The system scores and rates the company across multiple categories according to a which capabilities are applicable to the company, and which of the applicable capabilities the company actually utilized. The system applies a unique rating and point mapping approach to the capabilities utilized by the company. The point mapping approach is configured to facilitate clear delineation between average and above average companies, as well as an identification of which capabilities, if utilized, can put a company ahead of its competition. This information assists a company in efficiently prioritizing and identifying which improvements to its rendered services will have the greater overall impact, benefiting both the customer and the company itself, and allowing the company to effectively recognize, meet, and exceeding customer expectations. | 6 |
FIELD OF THE INVENTION
This invention relates to carbonated beverage machines and in particular to a portable apparatus for rapidly carbonating liquids with chemically generated carbon dioxide produced in a separate detachable apparatus.
The present invention is a further development of my prior invention which is described and claimed in my prior copending application Ser. No. 07/736,628 Filed Jul. 26, 1991 and allowed on Aug. 24, 1992.
BACKGROUND OF THE INVENTION
Carbonated beverages range in variety from carbonated water, knows as soda water or sparkling water, to a carbonated water flavored with natural or artificial flavors such as orange, lemon-lime, cola, and many more.
The amount of carbon dioxide gas dissolved into these products is usually referred to as Volume of CO 2 per Volume of Liquid. The higher the volume of CO 2 per unit Volume of Liquid, the greater the sparkle and effervescence of the beverage. Although the desirable level of carbonation in a beverage is a matter of personal preference, packaged soft drinks are usually made with 3.5 to 4.0 volumes of carbon dioxide for colas, 4.0 to 5.0 Volumes of CO 2 for seltzers and soda water and generally less that 3.0 volumes for orange flavor. One of the disadvantages of packaged carbonated beverages is that the carbonation level is fixed and not available at different levels to suit different personal tastes.
Other disadvantages of packaged carbonated beverages include the unnecessary cost of packaging and transportation of a product that is comprised essentially of water and the cost of disposal or recycling of the package. Still further is the problem that once the pressurized beverage container is open to the atmosphere, the beverage left unconsumed and unpressurized tends to lose carbonation and go flat thus wasting the unconsumed portion.
Several products have been developed to overcome the above noted problems and make possible the preparation of carbonated beverages in the home.
One such product is described in Norwegian Patent No. 52210. This device uses a high pressure metal cylinder to supply carbon dioxide to carbonate water. Disposable high pressure gas cylinders are sufficiently expensive to offset any price advantage sought through the use of a portable carbonation device. In addition, they are inconvenient to procure and present a waste disposal problem with the empty cylinder.
Furthermore, in operation, this device does not produce acceptable carbonation with a practical waiting period because a pressure equilibrium between the CO 2 cylinder and carbonate bottle is established soon after the CO 2 cylinder is connected to the bottle. This pressure equilibrium prevents further flow of gas from the cylinder until the CO 2 is gradually absorbed by the water.
U.S. Pat. No. 4,719,056 (Scott) also discloses a method of carbonating water with propellent carbon dioxide packaged in a high pressure metal cylinder. The method for dissolving carbon dioxide gas into water through use of high speed rotating vanes is a very effective means to achieve rapid carbonation at high CO 2 Volume levels; however, this device has the disadvantage of the cost of a source of rotating mechanical motion. A further disadvantage is the requirement of a rotary seal on the mixing shaft to separate the pressurized carbonation chamber from atmospheric pressure. Rotary seals are known to be prone to leakage and premature failure especially when they are used at the elevated pressures specified.
Home carbonating devices requiring the use of CO 2 gas packaged in gas cylinders as described by U.S. Pat. No. 4,719,056 (Scott) and U.S. Pat. No. 4,251,473 (Gilbey) are not practical for mass distribution for several reasons. If the cylinders are single use and, therefore disposable, the cost of the carbon dioxide and the cylinder spread over the quantity of carbonated beverage they produce is significantly higher than the cost of an equivalent quantity of packaged carbonated beverage. If the cylinders are the reusable type, the cost of the cylinder can, of course, be divided by the number of times it is refilled; however, refilling a CO 2 gas cylinder is inconvenient and expensive because the cost of labor to perform the refilling is far greater that the cost of the gas itself. Complicating this situation further is the limited number of CO 2 refill stations, since even in advanced economic societies, CO 2 gas refilling stations are generally limited to serving commercial and industrial users. In order to overcome the cost and inconvenience of gas cylinder as the source of carbon dioxide for a home carbonator, several devices that derive the carbonating gas from a chemical reaction have been developed.
One such apparatus described in U.S. Pat. No. 4,347,783 (Ogden) derives the carbon dioxide from a reaction of yeast and sugar or, alternatively, from a chemical reaction of an edible acid with a carbonate in an aqueous solution. One problem with the device is that it does not produce a satisfactory level of carbonation, i.e. at least 3 Volumes of CO 2 or more, in a reasonable period of time.
U.S. Pat. No. 4,040,342 (Austin) discloses a gas generating chamber with a gas conduit extending into a carbonating chamber. After the chemical reaction is activated, the carbon dioxide flows into the carbonating chamber and carbonates the liquid contained therein. There are several limitations and problems with this device.
First, the time required to carbonate the liquid to 3 or more Volumes of CO 2 is fifteen minutes or greater. This is because the process of dissolving carbon dioxide into liquid occurs in two mechanisms; one quite rapid and the other quite slow. Some of the gas dissolves into the liquid as it bubbles to the surface and fills the head space of the carbonation tank. This CO 2 solution process occurs quite rapidly though it is, of course, dependent upon the rate of the chemical reaction producing the CO 2 . Pressurized CO 2 in the head space acting upon the surface of the liquid is the other gas absorption mechanism. This absorption rate is slow because of the fixed interfacial exposure area between the CO 2 and the liquid. If this interfacial exposure area could be increased by agitation or by turbulent mixing as is taught by U.S. Pat. No. 4,719,056 (Scott) then CO 2 absorption would occur far more rapidly.
The other problem is the likely occurrence of transfer of some of the salt by-products of the CO 2 generation reaction into the liquid to be carbonated.
The reaction of edible acids (such as citric) with carbonates (such as sodium bicarbonate) in an aqueous solution is an endothermic reaction. When the reaction is first initiated, therefore, it is at its maximum temperature and its fastest reaction rate. In addition, the maximum amount of fuel for the reaction is present when it first begins. Therefore, during its initial stages the reaction produces considerable foaming and surface effervescence releasing a mist of reactant salt spray into the carbon dioxide gas being generated. This salt mist enters the carbonation chamber and ultimately the liquid being carbonated.
If hot water is used as the reactant water, the reaction rate is accelerated even further and salt contamination increases further.
U.S. Pat. No. 4,636,337 (Gupta) shows an apparatus that carbonates water rapidly with carbon dioxide generated in a reaction vessel from chemicals contained in a package. Water is added to the vessel containing the package and dissolves the package or package glue seams to expose the chemicals and react with them producing carbon dioxide gas.
One problem with this approach is that it requires a special water permeable (or soluble) package that will open and react with water after a delay time of immersion in the water. However, this delay time will vary according to the temperature of the reactant water and may begin before the user attaches the vessel to the carbonating apparatus; thus creating a potentially hazardous condition. Also, the possibility of reaction activation prior to attaching the vessel to the apparatus is always present if the user is distracted or delayed after adding water to the vessel containing the chemical package.
Further, the water soluble package containing the CO 2 producing chemicals must itself be contained in another package to prevent deterioration of the package and the chemicals contained therein by atmospheric humidity or exposure to water. As a result, there is a double packaging cost.
Finally, if the reactant water temperature is too high, some foaming and effervescence will occur in the reaction vessel causing reactant salt mist to enter the CO 2 gas conduit and contaminate the beverage therein.
For improved consumer convenience, the direct carbonation of premixed beverage is more desirable than the carbonation of unflavored water to which a flavoring must be added with each serving of soda water dispensed. With the Austin apparatus, U.S. Pat. No. 4,040,342, direct carbonation of premixed beverages would not be practical because premix flavoring syrups typically contain sugar and other ingredients that sufficiently alter the surface tension of the water syrup mix to cause the mixture to foam profusely; thus expelling much of the carbonation as it is dispensed from the pressurized carbonation vessel into a receptacle at atmospheric pressure. Most commercial soda fountains meter and mix flavoring syrup into the carbonated water after the water is dispensed from the pressurized carbonation vessel; therefore, when the syrup and carbonated water are combined, they are at atmospheric pressured (a process know in the industry as "post mix") and the foaming problem is avoided.
While the Gupta device does allow direct carbonation of premixed beverages, it does not solve the problem of the loss of carbonation in the unconsumed beverage portion left in the unpressurized container.
OBJECTS OF THE INVENTION
One object of this invention is to provide a means to rapidly carbonate liquids including premixed beverages, without the need for special water soluble packaging to contain the carbon dioxide producing chemicals.
Another object of the invention is to provide a means for re-pressurizing the container containing the carbonated beverage with CO 2 gas stored during the initial carbonation reaction.
A still further object of the invention is to provide an apparatus that governs the rate of reaction of the carbon dioxide generating chemicals to reduce the occurrence of reactant salt spray contamination of the beverage.
An even further object of the invention is to provide a portable, easy-to-store beverage carbonating chamber that also serves as a storage container with a releasable dispensing spout.
These and other objects of the invention will become more fully apparent in the following specification and the attached drawings.
SUMMARY OF THE INVENTION
This invention is a process and apparatus for rapidly carbonating a liquid beverage by providing a first pressure vessel and a second pressure vessel, detachably connecting the interiors of the first and second pressure vessel to each other with a gas conducting means, positioning a selected quantity of a carbon dioxide generating compound at a first location within the first pressure vessel, positioning a contained selected quantity of water at a second location within the first pressure vessel and sealing the vessel, filling a large portion of the second pressure vessel with a liquid beverage to be carbonated while leaving an unfilled headspace at the top of the vessel and sealing the vessel, releasing the contained quantity of water into the carbon dioxide generating compound in the first pressure vessel to chemically react with the compound and generate carbon dioxide gas in sufficient volume to increase its pressure causing the gas to pass into the second pressure vessel and partially carbonate the liquid beverage therein and fill the headspace with pressurized carbon dioxide, disconnecting the second pressure vessel from the first pressure vessel while retaining the gas pressure within both vessels, manually shaking the second pressure vessel to mix the liquid beverage and carbon dioxide gas therein to further carbonate the liquid beverage, and releasing the pressure from the second pressure vessel prior to pouring a desired amount of the carbonated beverage from the second pressure vessel.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of the invention showing a carbonation vessel separated from a carbon dioxide generator assembly;
FIG. 2 is a top plan view of the embodiment shown in FIG. 1 with the carbonation vessel operatively connected to the carbon dioxide generator assembly;
FIG. 3 is a side cross-sectional view of the carbon dioxide generator vessel and lid taken on line 3--3 of FIG. 2;
FIG. 4 is a front cross-sectional view of the carbon dioxide generator assembly taken on line 4--4 of FIG. 2 connected to the carbonation vessel;
FIG. 5 is a side elevational view of the carbonation vessel with portions broken away to show the internal structure;
FIG. 6 is a fragmentary cross-sectional view showing the latch mechanism and self sealing gas line coupling for connecting together the gas generating vessel and the carbonation vessel;
FIGS. 7A through 7C show a combined access opening and pouring spout on the carbonation vessel with a closure valve in three different positions;
FIG. 8 shows a top plan view of the carbon dioxide generator assembly with the top of the housing removed to show the structural details of the apparatus;
FIG. 9 is a cross-sectional view showing the internal structure of a carbonation vessel of another embodiment of the invention;
FIG. 10 is a cross-sectional view of a carbon dioxide generator vessel for connection to the carbonation vessel shown in FIG. 9; and
FIG. 11 is a cross-section view of the same carbon dioxide generator shown in FIG. 10 but taken at a different cross-sectional location from FIG. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, the numeral 10 indicates the overall apparatus which is a portable carbonation machine for rapidly carbonating liquid beverages. The carbonation machine 10 has a gas generator assembly 12 for producing carbon dioxide gas and a carbonation tank or pitcher 14 which is removeably connectable to the gas generator assembly 12 by a latch mechanism 16 and a quick-release pneumatic coupling 18 both of which project from a housing 20 of the gas generator assembly 12. The latch mechanism 16 and the coupling 18 are released by pressing a button 22 on the top of the housing. The latch mechanism 16 and coupling will be described later in more detail in a description of FIG. 6.
The housing 20 has a top portion 24 which can be removed for access to the working parts inside.
The carbonation tank 14 is shaped to form a pitcher, with a hollow cylindrical container 26, a handle 28 attached to the container 26 thereof and a removeable closure lid 30 having a seal ring 31 which sealingly engages the top of the container 26 and forms the carbonation tank or pitcher 14 as a pressure vessel for carrying out the carbonation of liquids. The lid 30 has a pour spout 32 which contains a closure valve 34 which will be explained later in detail relative to FIGS. 7A through 7B.
The housing 20 has a concave cavity 36 on one side thereof into which a portion of the carbonation tank 14 is inserted to engage the latch 16 and coupling 18.
Another side of the housing 20 has a rectangular opening 38 into which a cylindrical reaction vessel 40 having a handle 42 is inserted for sealing engagement with a closure lid assembly which will be shown and explained in detail later in other figures of the drawings.
A cam shaft lever 44 protrudes from a horizontal slot 46 in the housing 20 and has a tab shaped knob 48 for moving the cam shaft lever 44 from side to side and for rotating the lever 44 back and forth about its own longitudinal axis. The movement of the cam shaft lever 44 seals the reaction vessel 40 and starts a chemical reaction to generate carbon dioxide as will be explained later.
FIG. 2 shows a top plan view of the carbonation pitcher 14 operatively attached to the 12 gas generation assembly with the pitcher 14 nesting in the concave cavity 36. The cam lever knob 48 is shown in ghost line moved to the left as 48L and to the right as 48R.
Referring now to FIG. 3 showing a cross-sectional view of the reaction vessel 40 looking from one side and FIG. 4 showing the front of the reaction vessel 40 which is positioned within the housing 20 and located below a closure top 50 which is moveable upward from and downward into sealing engagement with the top edge of the reaction vessel 40 by rotation of a threaded cam ring 52 having internal threads 54 which engage external threads 56 on the closure top 50. The cam ring 52 is enclosed by a retaining ring 58 which is fixedly attached on opposite sides thereof by a pair of spaced apart opposed side plates 60. The side plates 60 are similarly attached at the bottom end to a base block 62 by rivets 64 or any other suitable means. The base block 62 is fastened to the housing 20 in any appropriate manner. A cap ring 66 fits on top of the retaining ring 58 and aids in holding the cam ring 54 and the lever 44 in position.
Thus it can be seen that when the lever 44 is moved from left to right as shown in FIGS. 1 and 8, it rotates the cam ring 52 causing the closure top 50 to move up and down in relation to the reaction vessel 40.
The lever 44 which is a round rod is rotatably and slideably mounted in holes 68 in the cam ring 52. The lever 44 carries a large eccentric cam 70 and a smaller eccentric cam 72. A spring 74 biases the lever to the right or with the knob 48 in an extended position. As shown in FIGS. 3 and 8, a curved wall extension 76 on the retaining ring 58 prevents the lever 44 from being pushed in when it is in either the left or center positions shown in FIG. 8. When the lever 44 is moved to the far right position shown it FIG. 8 it can be pushed in the longitudinal direction since it clears the end of the curved wall 76. The reason for moving the lever 44 in this manner will be explained later.
The closure top 50 of the reaction vessel 40 has a center hole 78 through which extends a vertically slideable actuator pin 80 which is biased in an upward position by a spring 82. The pin 80 is forced in a downward position by the cam 70 when the lever 48 is rotated 180° from the position shown in FIG. 3.
As shown in FIG. 3, a water canister 84 is removeably positioned within the reaction vessel 40. The canister 84 has a cylindrical sidewall 86, a spider member 88 extending across the open top of the canister 84 and slideably supporting a center pin 90 which carries a disk shaped bottom 92 which sealingly engages the bottom edge of the sidewall 86. The pin 90 is biased upwardly by a spring 94 so that the bottom 92 is held in sealing in engagement with the sidewall 86 to contain water placed in the canister 84.
The closure top 50 has an annular recess 96 in the bottom which carries a seal ring 98. The seal ring 98 seals against the upper edge of the reaction vessel 40 when the top 50 is clamped downward against the vessel 40 as will be explained later.
As shown in FIG. 4, the top 50 has a gas outlet port 100 which contains a filter 102 and is connected to a gas transmission line 104. The gas line 104 extends from the top 50 to a male portion 18M of coupling 18 extending from the bottom of the housing 20. The top 50 also has a safety pressure release valve 106 and a cam operated vent valve 108 shown in FIG. 8 which is opened and closed by operation of the cam 72.
Referring now to FIG. 5 the carbonation pitcher 14 is as previously described in FIG. 1 removeably attached to the gas generation assembly 12 by a latch mechanism 16 which is shown in detail in FIG. 6. The latch mechanism mounted within the housing 20 has a catch 110 which engages a slot 112 in the side of the pitcher 14. The catch 110 is carried on an elongated flat slide bar 114 which is moveable up and down with respect to the housing 20 by pressing the button 22. The bar 114 carries a horizontal extension tab 116 which engages a spring biased clip 118 on the female portion 18F of coupling 18 on the pitcher 14.
As the pitcher 14 is pushed into interlocking relationship with the gas generation assembly 12, the male portion 18M engages the female portion 18F to connect the gas transmission line 104 to a further extension of the line 104a in the bottom of the pitcher that in turn connects to a gas dispersion nozzle inside pitcher 14 at the bottom thereof. At the same time as the coupling 18 is connected, the catch 110 engages the slot 112 and locks the pitcher 14 and gas generator 12 together. The spring biased clip 118 pressing upwardly against the extension 116 holds the catch 10 in locked position in the slot 112. To release the pitcher 14 from the assembly 12, the button 22 is pressed down overcoming the upward bias of the clip 118 and permitting the catch 110 to be released from the slot 112 in the pitcher. When the pitcher 14 is removed from the assembly 12, the coupling portions 18M and 18F separate and simultaneously an internal valve (not shown) within each coupling seals the opening to the respective portion of the gas line 104 and 104a, thereby sealing off both the reaction vessel and the interior of the carbonation pitcher from the outside atmosphere and retain pressure within each pressure vessel.
A safety pressure release valve 122 is located in the lid 30 of the pitcher 14 to relieve any excess pressure from the interior of the pitcher.
The pour spout 32 and closure valve 34 of the pitcher 14 and shown in detail in FIGS. 7A through 7C. FIG. 7A shows the valve 34 in the closed and sealed position. The valve 34 has a center stem 124 passing through a spider member 126 which bridges a pour opening 128 in the bottom of the spout. The lower end of the stem 124 passes through a center opening 130 in an annular stopper 132 which has a seal ring 134 which seals against an annular inwardly facing valve seat surface 136 surrounding the pour opening 128. The Stem 124 has a seal ring 138 on the lower end thereof which seals against an annular inwardly inclined seat 140 at the bottom of the center opening 130. The stem 124 is biased upwardly by a spring 142 which in turn hold both the seal rings 134 and 138 against their respective seats 136 and 140 thereby sealing the pitcher 14 to the outside atmosphere. The stem 124 has a pair of radially outwardly extending ribs 144 which pass through slots 146 in a center hole 148 of the spider 126.
FIG. 7B shows the stem 124 depressed to move the seal 138 down from the seat 140 and restrictively vent the pitcher 14 and release internal pressure therefrom.
In FIG. 7C the stem 124 is depressed even further to move the stopper 123 down from sealing engagement with the seat surface 136. The stem 124 is then rotated about its axis so that the flanges 144 are moved out of alignment with slots 146 and engage the bottom of the spider 126 and hold the stopper 132 in the open position to permit pouring from the pitcher 14. To close the stopper 132 the stem 124 is rotated until the flanges 144 are again aligned with slots 146 and then the stem 124 is moved upwardly by the spring 142 and closes the pour opening 128.
In operation the lid 30 of the carbonation pitcher 14 is removed and water, ice and beverage flavoring are added to the proper levels. The lid 30 is placed back on the container 26 and rotated 1/4 turn to cause the lid 30 to seal. The Pitcher 14 is then pneumatically connected to the reaction vessel 40 of the gas generation assembly 12 by pushing the pitcher 14 into the cavity 36 thus causing the catch 112 to engage the slot 112 in the pitcher 14 and simultaneously causing the male coupling 18M to engage the female coupling 18F as previously described in the discussion of FIG. 6.
To produce Carbon dioxide gas, the reaction vessel 40 is removed from the housing 20 and a packet of CO 2 producing chemicals is emptied into the vessel 40. The water canister 84 is filled with room temperature water and placed in a suspended location in the upper portion of the reaction vessel 40 above the chemicals. The vessel 40 is then placed back inside the housing 20 in position beneath the closure top 50.
The cam lever 44 is then moved to the right causing the closure top 50 to move down and seal against the top edge of the reaction vessel 40 thereby closing the vessel. The cam lever 44 is then pushed inward closing the vent 108 in the top 50. The cam lever 44 is then rotated 180 degrees about its own axis causing the cam 70 to bear against the pin 80 and move it downwardly to bear against the center pin 90 and force open the bottom 92 of the canister 84, thereby dumping the water from the canister onto the chemicals in the bottom of the reaction chamber and starting the chemical reaction generating the carbon dioxide gas.
The carbon dioxide gas produced by the reaction passes through the porous filter 102, through the gas transmission line 104, through the coupling 18, through line portion 104a and out of the gas dispersion nozzle 120 into the water or beverage to be carbonated in the carbonation pitcher 14.
The carbonation pitcher 14 head space built into the lid 30 has a minimum cavity volume of 400 ccs when the pitcher's fluid storage capacity is two liters. The generation of CO 2 is at its maximum rate immediately after the reaction is first initiated then, as the reaction continues, the rate of CO 2 evolution slows. In order to throttle or govern the initial reaction rate and thus minimize foaming and entrainment of reaction salt mist into the carbon dioxide being evolved, a gas flow restrictor 103 is located on the inlet end of the gas transmission line 104. Since this restrictor limits the flow rate of CO 2 through the gas line 104, an almost instantaneous back pressure develops within the reaction vessel. This back pressure significantly reduces the rate of reaction effervescence bubbling and salt mist generation thus preventing salt contamination of the beverage. If any airborne salts are produced, they are trapped in the in-line filter 102.
As the reaction continues carbon dioxide passes through the dispersion nozzle 120, then bubbles through and is partially absorbed by the beverage. The CO 2 not absorbed rises to the head space cavity increasing the pressure therein until the reaction chemicals are consumed, about 3.5 minutes after reaction initiation. The pressure relief valve 122 in the lid 30 of the pitcher 14 will open if the head space pressure exceeds 90 psi, (6.328 kg/sq cm). The reaction vessel 40 is sized so that only enough CO 2 generating chemicals may be added to it to generate 90 psi, (6.328 kg/sq cm) in the head space of the carbonation pitcher 14. However, in the event that the reaction vessel 40 is overcharged with CO 2 generating chemicals, the relief valve 122 will open. The relief valve 106 in the closure top 50 of the reaction vessel 40 performs the same function to relieve excess pressure if the gas transmission line 104 were to become blocked in any way.
About 10 minutes after the reaction was initiated, the beverage in the carbonation pitcher 14 will be carbonated to a level of 2.0 to 2.5 Volumes of CO 2 increasing to 3.0 to 3.5 Volumes of CO 2 after a total of about 20 minutes.
The carbonation pitcher 14 may be disconnected from the gas generator assembly 12 by pushing the button 22 that releases the catch 110 and the quick-disconnect clip 118 which releases the male coupling 18M from the female coupling 18F. As the pitcher 14 is pulled away from the assembly 12, a ball check valve inside of the couplings 18M and 18F closes them and seals both the pitcher 14 and the reaction vessel 40 thus maintaining internal pressure in both vessels. To decrease the time for achieving full carbonation to about 4 minutes, the carbonation pitcher 14 may be removed from the gas generator assembly 12 about 31/2 minutes after the CO 2 reaction was initiated and then manually shaken for approximately ten seconds.
This shaking action causes the pressurized gas in the head space of the pitcher 14 to intermix with the beverage, greatly increasing the interfacial exposure area between the liquid and the gas, therefore causing rapid absorption of the pressurized CO 2 into the liquid. After ten seconds of shaking, the beverage is carbonated to a level of 4.0 to 4.5 volumes and is ready to serve, the accumulated time since initiation of the reaction totalling about 4 minutes.
The pitcher 14 should be allowed to stand for approximately one minute to coalesce any undissolved gas bubbles thus avoiding foam-up when the pitcher spout 32 is opened.
To open the pour spout 32, the valve stem 124 is depressed allowing a gradual restrictive venting of internal pressure to further minimize foaming the beverage while the pitcher 14 is decompressed to atmospheric pressure. An abrupt pressure drop would cause rapid surface turbulence of the beverage accelerating the creation of foam and loss of carbon dioxide from the beverage.
Carbonated beverage left uncomsumed and stored in the pitcher will gradually lose carbonation as the CO 2 leaves the beverage to reach equilibrium with atmospheric pressure. In order to preserve the original level of carbonation in the uncomsumed beverage, the spout 32 of the pitcher 14 is closed by rotating the stem 124 to cause it to pull the stopper 132 into sealing engagement with the pour opening 128 thus sealing the interior of the pitcher 14 to the atmosphere.
If desired, the pitcher 14 may then be reconnected to the gas generator assembly 12 including the reaction vessel 40 so that CO 2 left stored in the vessel 40 will flow into the carbonation pitcher 14 until pressure equilibrium is attained between the vessels 14 and 40. The repressurization of the pitcher 14 will slow or stop CO evaporation from the beverage and maintain its carbonation.
The embodiment shown in FIGS. 9 through 11 is quite similar to the previously described embodiment of FIGS. 1 through 8 except that the gas generator 212 is not enclosed in a housing such as the housing 20 and the manner of closing the top of the reaction vessel is different. The carbonation pitcher 214 is substantially identical to the pitcher 14 in the previous embodiment except that the apparatus for connecting the pitcher 214 and the gas generator 212 is somewhat different from the latch mechanism 16 in the prior embodiment.
Referring now to FIGS. 10 and 11, a carbonation machine is indicated generally by the number 210. The two primary components of the machine 210 is the gas generator 212 and the carbonation tank or pitcher 214 which are joined together by a connecting lug 216 which clamps onto a ledge 217 on the pitcher 214 and the male coupling 218M on the gas generator 212 which engages the female coupling 218F on the pitcher and are held together by a spring biased clip 220 as shown in FIG. 9.
The carbonation pitcher 214 in FIG. 9 has container 222 with a handle 224 attached thereto. A screw on lid 226 is held in position with external threads 228 which engage internal matching threads 230 on the container 222. The lid has a seal ring 231 which seals it to the pitcher to create a pressure vessel. The lid 226 has a pour spout 232 which is substantially identical to the spout 32 shown in FIGS. 7A through 7C and works in the same manner. For the interest of brevity it will not be described in detail except to say that it has a spring biased stem 236 which holds a stopper 236 in sealing engagement in the pour opening 238. The stem 234 is used to release pressure from the pitcher 214 by pressing down on it and the stopper 236 is opened and locked open in the same manner as previously described regarding the pour spout 32 in the previously described embodiment. The lid 226 also has a pressure relief valve 240 to relieve excess pressure from the pitcher 214. At the bottom of the pitcher 214 the female coupling 218F is connected to male coupling 218M and held in position by clip 220. The coupling 218F also connects to a short length of gas transmission line 242 leading to the gas dispersion nozzle 244 which passes carbon dioxide gas into the bottom of the pitcher 214 where it mixes with water or liquid beverage placed therein.
Referring now again to FIGS. 10 and 11, the gas generator 212 has a reaction vessel 246 with an open top which is sealingly closed by a closure top 248 to form a pressure vessel in which the generation of carbon dioxide may be carried out. The top 248 is connected by a pivot arm 250 to a handle 252 at pivot pin 254. To close the reaction vessel 246 the top 248 is swung down on top edge of the vessel 246 and a retaining ring 256 is screwed onto the top of the vessel 246. To open the vessel 246 the ring 256 is unscrewed and the closure top 248 is swung back supported by the pivot arm 250 as shown in ghost lines in FIG. 10. A water canister 258 is mounted inside the vessel 246 in the same manner as previously described in the prior embodiment. The canister 258 has a spider support 260 through which passes a support pin member 262 which carries a bottom 264 which sealing engages a cylindrical sidewall 266. A spring 268 biases the pin 262 upwardly to cause the bottom 264 to seal against the sidewall 266. A seal ring 270 seals the top 248 to the vessel 246. The top 248 carries a rotatable cam shaft 272 having a knob 274 and cams 276, 278 and 280. The cam 276 engages a spring biased pin 282 extending through the top 248 which in turn presses down on the pin 262 and opens the bottom 264 when the cam shaft 272 is rotated about its axis and dumps the water from the canister 258 onto carbon dioxide generating chemicals placed in the bottom of the vessel 246. The cam 278 opens and closes a vent valve 284 with the valve being closed when carbon dioxide is being generated and opened to release pressure prior to opening the closure top 248.
The cam 280 contacts a top edge of the retaining ring 256 and prevents the cam shaft 272 from being rotated to a position which releases the water and starts the chemical reaction until the top 248 is closed and the retaining ring 256 is screwed down to hold the top 248 on the vessel 246. The cam shaft 272 can be rotated only when the ring 256 is fully screwed down and this prevents premature release of the water. This is because the ring 256 must be in a circumferential position where the cam 280 is aligned with a depressed portion 281 on the ring 256 which permits the cam 280 and the shaft 272 to rotate.
The cam 280 engages the depressed portion 281 on the top edge of the retaining ring 256 and prevents the retaining ring 256 from being unscrewed until the vent valve 284 is opened to release internal pressure from the vessel 246. As shown in FIG. 11, a gas outlet port 285 connects to a gas transmission line 286 which in turn connects to the male coupling 218M at the bottom of the vessel 246. A filter 288 and a ball check valve 290 is located in the outlet port 285. The closure top 248 has a pressure relief valve 291 to release excess pressure from the vessel 246. The closure top 248 and the various working parts thereof are covered by a cap 292.
The operation of the embodiment shown in FIGS. 9 through 11 is substantially the same as that for the previously described embodiment in FIGS. 1 through 8 and will not be described in detail for simplicity. The primary difference is that the closure top 248 is pivotally connected to the handle 252 and is fastened to the reaction vessel 246 by manually screwing the retaining ring 256 onto the vessel 246 after the couplings 218M and 218F have been connected thereby pneumatically connecting the reaction vessel 246 and the carbonation pitcher 214.
In both embodiments of FIGS. 1-8 and FIGS. 9-11 the gas pressure is released gradually from the carbonation pitcher 214 by a restrictive vent valve since certain types of beverages would generate a large amount of foam if the pressure were released too rapidly.
In addition to the two embodiments shown herein, Various other embodiments may be used without departing from the scope of the invention. | A beverage carbonator having a pitcher shaped carbonation vessel which is detachably pneumatically connected to a reaction vessel in which carbon dioxide is produced by releasing internally stored water into a carbon dioxide generating chemical and passing the carbon dioxide into the carbonation vessel where it is dissolved into a liquid beverage. The carbonation vessel can be reconnected to the reaction vessel to recarbonate the unused portion of the beverage after it loses carbonation over a period of time and then disconnected for pouring the remainder of the beverage from the carbonation vessel. | 1 |
BACKGROUND OF THE INVENTION
The present invention generally relates to blood collection systems and methods of blood collection and, more particularly, it relates to autologous blood recovery systems, methods of blood recovery and blood transfer, and blood collection reservoirs, wherein blood recovery receptacles connected to a suction source can simultaneously collect and release blood.
There have been introduced into the marketplace a number of direct whole blood cardiotomy reservoirs and methods for using reservoirs during the recovery and collection of blood for subsequent reinfusion into a patient. Typically, a system might utilize a negative pressure source for blood delivery and collection in a reservoir and use the force of gravity for return of the collected blood to the patient. Alternatively, instead of using gravity, a roller pump or an intravenous pump might be used for reinfusion of blood collected to increase the rate of blood return to the patient. In each system, the blood collection reservoir cannot be used to simultaneously collect blood using negative pressure and reinfuse the blood using positive pressure, gravity or pressure above atmospheric.
Other autotransfusion systems in the marketplace incorporate disposable flexible liners in either blood collection or blood transfer reservoirs. In one instance, during blood collection, a negative pressure source is used to convey blood to the collection reservoir and thereafter the collected blood is transferred to a second liner reservoir for gravity feed return to the patient. If desired, the second liner reservoir can be subjected to external pressurization, internal pressurization cannot be utilized because of liner flexibility, to enhance the rate of blood reinfusion. As before, this type of system is not capable of simultaneously drawing and reinfusing blood. An additional disadvantage of this type system is that suction in the surgical field can be interrupted during liner changes.
Another marketplace liner system employs a liner reservoir in a single used hard plastic housing. The system utilizes negative pressure to convey blood from the operative field into the liner. When the liner is full, another unit is used. The first liner reservoir is then removed for blood processing or for reinfusion directly into the patient. Reinfusion may be achieved utilizing gravity or the rigid housing may be pressurized to accelerate reinfusion. As with the foregoing systems, this system is not capable of simultaneous blood collection and blood reinfusion. Also, the liner reservoir is a single use disposable item.
The liner reservoir systems have not been entirely satisfactory in the blood collection field. The systems have a long history of liner leaks and failure to adequately serve the surgical community. Additionally, the systems are labor intensive and difficult to handle when not routinely used.
The primary objective of the present invention is to advance the art field of surgical autologous blood recovery by providing a unique blood collection reservoir for use in intraoperative blood recovery systems. A characteristic feature of the collection reservoir, which is not found in the aforementioned systems devices, is its capability of maintaining a continuous predetermined suction while emptying the contents just previously collected in the reservoir. The simultaneous fill and draw property of the present reservoir cannot be found in existing blood collection reservoirs. Also, the reservoir eliminates the attendant disadvantages previously noted with respect to known systems reservoirs (leaking, suction interruption, pressurization, single use) and presents a simple, uncomplicated, multi compartment device which is easy to manufacture and use. Accordingly, we have invented an improved blood collection reservoir and system uniquely capable of simultaneously achieving an uninterrupted flow of blood into the reservoir for collection while releasing collected blood from the reservoir for processing or reinfusions.
SUMMARY OF THE INVENTION
The invention pertains to a novel fluid collection reservoir, particularly suitable for collecting blood, wherein the reservoir comprises an inlet and an outlet, a plurality of fluid collecting compartments, means for establishing a negative pressure in two or more of the compartments, and means for selectively isolating each of the compartments for collecting and transferring fluid through the reservoir. Preferably, the reservoir has three compartments. Fluid may flow out of the reservoir under gravity conditions or a pressure source may be provided to assist in delivery of fluid out of the reservoir. The reservoir might additionally include a first filter for gross particulate removal and foam reduction and a second filter for bacteria removal. Also, the reservoir might include a means for equalizing pressure between contiguous compartments.
In one embodiment, the reservoir is a blood collection reservoir comprising a housing defining a collection chamber having a plurality of compartments; an inlet for introducing blood into the collection chamber; means for providing fluid flow communication between a first of the compartments and a second of the compartments; means for creating a first fluid seal between the second compartment and a third of the compartments; means for establishing a negative pressure in the first and the second compartments; means for creating a second fluid seal between the first and the second compartments while maintaining the first fluid seal; means for releasing the first fluid seal and providing fluid flow communication between the second and the third compartments; and an outlet for conveying blood out of the collection chamber. The reservoir might further include means for reestablishing the first fluid seal, and means for releasing the second fluid seal and reestablishing fluid flow communication between the first and the second compartments while maintaining the reestablished first fluid seal. Also provided is a means for equalizing pressure between the second and the third compartments before releasing the first fluid seal. Further contemplated to be within the scope of the invention is an autologous blood recovery system employing the blood collection reservoir.
The present invention further contemplates a blood collection method comprising the steps of
(a) establishing a connection between a reservoir and an inlet of a housing including a collection chamber having a plurality of compartments, said inlet being in fluid flow communication with said collection chamber;
(b) providing fluid flow communication between a first of said compartments and a second of said compartments;
(c) creating a first fluid seal between said second compartment and a third of said compartments;
(d) establishing a negative pressure in said first and said second compartments, with said negative pressure being sufficient for conveying and maintaining a flow of blood from said reservoir into said collection chamber;
(e) introducing said blood into said first compartment for passage therethrough and collection in said second compartment;
(f) creating a second fluid seal between said first and said second compartments while maintaining said first fluid seal and collecting blood in said first compartment;
(g) releasing said first fluid seal providing fluid flow communication between said second and said third compartments, passing into said third compartment blood collected in said second compartment; and
(h) establishing a connection between an outlet in said collection chamber and a patient for conveying and infusing the blood into said patient.
Additionally included could be the steps of
(i) reestablishing said first fluid seal; and
(j) releasing said second fluid seal and reestablishing fluid flow communication between said first and said second compartments while maintaining said reestablished first fluid seal, passing into said second compartment blood collected in said first compartment.
followed by the steps of
(k) maintaining said negative pressure; and
(l) repeating steps e through k, thereby maintaining an uninterrupted flow of blood into and delivery of blood out of said collection chamber.
An alternative method would include the added step of establishing a positive pressure in said third compartment. Further contemplated to be within the scope of the invention is an autologous blood collection method.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific results obtained by its use, reference should be made to the corresponding drawings and descriptive matter in which there are illustrated and described typical embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fluid collection reservoir, particularly suitable for collecting blood, in accordance with the principles of the present invention, illustrating a general overall view of the reservoir.
FIG. 2 is an enlarged cross-sectional view taken along line 2--2 of the reservoir depicted in FIG. 1 and showing the reservoir in a first fluid collecting operation.
FIG. 3 is a view like that of FIG. 2 but showing an isolation and holding of previously collected fluid while additional fluid is being collected.
FIG. 4 is a view like that depicted in FIGS. 2 and 3 but showing the reservoir transferring fluid previously isolated and delivering fluid out of the reservoir while simultaneously collecting additional fluid.
FIG. 5 is similar to FIG. 4 but showing an empty and segregated fluid isolation chamber.
FIG. 6 is a view substantially as the fluid collecting operation depicted in FIG. 2 but while also depicting the simultaneous delivery of fluid out of the reservoir.
FIG. 7 is substantially the illustration provided in FIG. 3 but also showing the simultaneous delivery of fluid out of the reservoir.
FIG. 8 is a view of the lower portion of the reservoir depicting an alternate configuration for reservoir activation.
FIG. 9 is a view of another reservoir construction, the view being similar to FIG. 2 but without fluid collection, showing a modified internal reservoir activation mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The description herein presented refers to the accompanying drawings in which like reference numerals refer to like parts throughout the several views. First turning to FIG. 1, there is illustrated a perspective view of blood collection reservoir 10 of the present invention depicting a general view of the reservoir. It should be understood that, while a blood collection reservoir will be described, the reservoir would be suitable for collection of other fluids. Reservoir 10 includes rigid housing portion 12, blood inlet port 14, vacuum port 16, collection chamber 18 having compartments 20, 22 and 24, blood outlet port 26 and hanger 28. Turning next to FIG. 2, which shows the reservoir schematically in a first blood collection step, with blood B shown entering inlet 14 upon the imposition of a vacuum V through vacuum port 16. Inlet 14 is connected to a blood source and vacuum port 16 is connected to a suitable source of suction. Compartments 20 and 22 are in fluid flow communication, both compartments being under vacuum, through a central opening through which the blood flows into compartment 22 for collection. Compartments 22 and 24 are sealed off from one another by means of valve 30 which forms a fluid tight seal between the two compartments. Valve 30 is held closed by spring 32, which is under compression, causing the seating of the valve and sealing of a central opening between compartment 22 and 24. Also shown in FIG. 2 is lever 34 engaging elongated member or rod 36 (the upper portion in this view being coupled to the lower portion by spring 38), spring 40 and valve 42 being supported by member 36. Additionally provided are filter 44, used for gross particulate removal and foam reduction, and baffle 46 which serves to divert blood away from vacuum port 16 to keep blood from exiting through the vacuum port. There is furthermore provided a port 48 which can serve to selectively pressurize compartment 24 as shown by P. Pressurization P can be achieved by using a sphygmomanometer bulb, a pressure gauge, and tubing (all of which are not shown) communicating with port 48. Pressure is preferably maintained from about atmospheric up to about 200 millimeters of mercury. Pressurizing air or gas entering compartment 24 through port 48 may be filtered using a bacterial filter (not shown) having a pore size less than one micron but preferably a pore size equal to or less than 0.45 microns. Alternatively, port 48 can be used to vent compartment 24 to atmosphere or ambient and, in this situation, a bacterial filter could also be used to prevent blood contamination. Lastly shown in FIG. 2, are filter 50, vents 52, seal rings 54 and passageway or channel 56. In this view, seal rings 54 close passageway 56 from vents 52 so that this path of communication between compartments 22 and 24, in addition to the compartmental sealing by valve 30, remains closed. However, the design is such that pressures between compartments 22 and 24 may be equalized through the displacement of seal rings 54 to open communication between vents 52 and channel 56 before valve 30 is unseated to open the larger central opening between the compartments. This equalization of pressure between compartments 22 and 24 is particularly important when compartment 24 is pressurized above atmospheric.
Turning now to FIG. 3, there is shown lever 34 being moved downwardly, causing the downward displacement of member 36, and the downward movement of valve 42 which seats to seal compartments 20 and 22 from one another. Valve 30 remains closed and blood is continuously being collected in compartment 20. FIG. 4 depicts another step in the blood collection process wherein upon further downward movement of lever 34, member 36 is further displaced downwardly, spring 32 is further compressed and valve 30 is forced downwardly for unseating. It should here be noted that the pressure equalization between compartments 22 and 24 through open vents 52 and passageway 56 (see arrows) occurred after upper seal ring 54 passed vents 52 and before unseating of valve 30, with spring 38 being placed in tension and spring 40 being compressed. In this view, valve 30 is unseated, releasing the previously established seal between compartments 22 and 24, and the blood previously collected and held in compartment 22 is allowed to flow into compartment 24. Meanwhile, valve 42 remains seated and blood continues to be collected in compartment 20. Also in this view, blood is shown exiting blood outlet port 26 while blood is simultaneously being collected. Pressurization of compartment 24 is accomplished to assist in the delivery of blood out of the reservoir. Alternatively, gravity delivery could have been employed.
FIG. 5 depicts the next sequence in the collection and delivery process wherein the direction of movement of lever 34 is reversed so that valve 30 is again seated to create a fluid seal between compartments 22 and 24. The energy stored in springs 32, 38 and 40 assist lever 34 in this return direction. It should be noted that valve 42 remains seated after the reseating of valve 30 and that blood continues to be simultaneously collected in compartment 20 while blood is delivered out of the reservoir through blood outlet port 26. FIG. 6 shows the next collection and delivery sequence wherein lever 34 is returned to its starting location. Member 36 has moved upwardly (assisted by energy stored in compressed spring 40) and valve 42 is unseated for allowing blood collected in compartment 20 to flow into compartment 22. Valve 30 remains seated and blood continues to be drawn into and delivered out of reservoir 10. FIG. 7 depicts the view substantially as that shown in FIG. 3 but additionally shows previously collected and transferred blood flowing out of compartment 24. The loop is now complete and the next step would be to repeat the FIG. 4 illustration.
Turning next to FIG. 8, there is shown an alternate embodiment of lever 34. Here there is depicted a lever 34', which forms a finger grip, and extension 35, which can be placed in the palm of a hand, so that the movement of member 36 and operation of internal reservoir structure as heretofore described can be accomplished by moving lever 34' in the directions indicated by the arrows. Counterclockwise movement of lever 34' performs the functions achieved through the downward movement of lever 34. Likewise, the return clockwise movement of lever 34' achieves the functional result of moving lever 34 upwardly.
Lastly, turning to FIG. 9, there is shown the structure of reservoir 10 much like that depicted in FIGS. 2-7. Here we have designated the reservoir 10' and the different structural features depicted are valve 42', valve guide ribs 41 and seal ring 43. Spring 38 has been eliminated and elongated member 36 is continuous from lever 34 to valve 42 which is secured to member 36. Movement of valve 42', upon activation of lever 34 as heretofore described, is shown by the arrows. Upon deflection of lever 34, valve 42' moves downwardly and seal ring 43 creates a fluid seal between compartments 20 and 22. The movement of parts, collection and transfer of blood and delivery of blood out of reservoir 10' are as described in respect to reservoir 10. Additional features depicted in this view are ball float valve 58 (designed to prevent blood flow out of vacuum port 16) and medication port 60 (included so that medicine may be added to the blood if desired.
A method of blood collection can be accomplished using either a patient or a reservoir as a blood source and collecting blood into and delivery out of the above-described inventive reservoir for conveyance of the collected blood to either the patient or a reservoir. Operation of the inventive reservoir would be as previously described.
It should be appreciated that the reservoir herein disclosed is so designed that preferably the blood flow path through the reservoir is as shown in the drawing figures. A blood flow path as shown, with blood cascading along the reservoir walls and central blood flow control mechanism, would present a smooth blood transport pathway to reduce the amount of turbulence and subsequent risk of hemolysis.
While in accordance with provisions of the statutes there are described herein specific embodiments of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims appended hereto without departing from the scope and spirit thereof, and that certain features of the invention may sometimes be used to an advantage without corresponding use of the other features. | An intraoperative blood recovery system and method for salvaging operative blood while simultaneously delivering previously collected blood to a reinfusion system. A blood collection and transfer reservoir, having multiple compartments which can be separated by vacuum or pressure barriers, is designed to maintain a continuous suction for blood inflow while blood previously collected can be simultaneously transported through the reservoir to achieve an uninterrupted flow of blood into and delivery of blood out of the reservoir. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional of U.S. Ser. No. 09/202,015 filed Dec. 8, 1998, which is a 371 of PCT/US97/10030 filed Jun. 18, 1997; priority based on Provisional Application No. 06/022,336 filed Jul. 24, 1996.
BACKGROUND OF THE INVENTION
The diphenyl-cyclopropene derivatives of the instant invention are kappa opioids useful in the treatment of pain, inflammation, Parkinsonism, dystonia, cerebral ischemia, diuresis, asthma, psoriasis, irritable bowel syndrome, and stroke.
The compounds are K-agonists which are centrally acting and peripherally selective acting.
SUMMARY OF THE INVENTION
The instant invention is a compound of Formula I ##STR1## or a pharmaceutically acceptable salt thereof wherein X is ##STR2## n is an integer of from 0 to 4; and R' is halogen, CF 3 , NO 2 , OR 2 , CONR 3 R 4 , or NHCOCH 3 wherein R 2 , R 3 , and R 4 are each independently selected from hydrogen and alkyl of from 1 to 6 carbons.
R is hydrogen, COOH, or COOCH 3 .
Particularly useful are the compounds selected from:
2,3-Diphenyl-cycloprop-2-enecarboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide;
2,3-Diphenyl-cycloprop-2-enecarboxylic acid methyl-(7-pyrrolidin-1-yl-1-oxa-spiro[4.5]dec-8-yl)-amide;
Ethyl 2-(3-chlorophenyl)-3-phenylcycloprop-2-ene-1-carboxylate;
2-(3-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid;
2-(3-Chlorophenyl)-3-phenyl-cycloprop-2-enecarboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide;
Ethyl 2-(4-chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylate;
2-(4-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid;
2-(4-Chlorophenyl)-3-phenyl-cycloprop-2-enecarboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide;
1-[Methyl-(2-pyrrolidin-1-yl-cyclohexyl)-carbamoyl]-2,3-diphenyl-cycloprop-2-enecarboxylic acid methyl ester; and
1-[Methyl-(2-pyrrolidin-1-yl-cyclohexyl)-carbamoyl]-2,3-diphenyl-cycloprop-2-enecarboxylic acid.
DETAILED DESCRIPTION
In the compounds of Formula I above, the phenyl groups may be unsubstituted or substituted by 1 to 3 substituents each independently selected from halogen, CF 3 , NO 2 , OR 2 , CONR 3 R 4 wherein R 2 , R 3 , and R 4 are each independently hydrogen or alkyl with from 1 to 6 carbons, and NHCOCH 3 . Preferred substituents are halogens, especially a monochloro group.
Compounds of the present invention contain one or more asymmetric carbon atoms and therefore exist in various stereoisomeric forms. Additionally, the compounds of this invention exist in different geometric isomeric forms. The instant invention is all geometric and stereoisomeric forms.
The compounds of the present invention and/or their nontoxic, pharmaceutically acceptable acid addition salts may be administered to mammals in pharmaceutical compositions which comprise one or more compounds of this invention and/or salts thereof in combination with a pharmaceutically acceptable nontoxic carrier.
As parenteral compositions, the compounds of this invention may be administered with conventional injectable liquid carriers such as sterile, pyrogen-free water, sterile peroxide-free ethyl oleate, dehydrated alcohols, polypropylene glycol, and mixtures thereof.
Suitable pharmaceutical adjuvants for the injectable solutions include stabilizing agents, solubilizing agents, buffers, and viscosity regulators. Examples of these adjuvants include ethanol, ethylenediamine tetraacetic acid (EDTA), tartrate buffers, citrate buffers, and high molecular weight polyethylene oxide viscosity regulators. These pharmaceutical formulations may be injected intramuscularly, intraperitoneally, or intravenously.
As solid or liquid pharmaceutical compositions, the compounds of the present invention may be administered to mammals orally in combination with conventional compatible carriers in solid or liquid form. These orally administered pharmaceutical compositions may contain conventional ingredients such as binding agents such as syrups, acacia, gelatin, sorbitol, tragacanth, polyvinylpyrrolidone, and mixtures thereof.
The compositions may further include fillers such as lactose, mannitol, starch, calcium phosphate, sorbitol, methylcellulose, and mixtures thereof.
These oral compositions may also contain lubricants such as magnesium stearate, high molecular weight polymers such as polyethylene glycol, high molecular weight fatty acids such as stearic acid, silica, or agents to facilitate disintegration of the solid formulation such as starch, and wetting agents such as sodium lauryl sulfate.
The oral pharmaceutical compositions may take any convenient form such as tablets, capsules, lozenges, aqueous or oily suspensions, emulsions, or even dry powders which may be reconstituted with water or other suitable liquids prior to use.
The solid or liquid forms may contain flavorants, sweeteners, and/or preservatives such as alkyl p-hydroxybenzoates. The liquid forms may further contain suspending agents such as sorbitol, glucose, or other sugar syrups, methyl-, hydroxymethyl-, or carboxymethylcellulose, and gelatin, emulsifying agents such as lecithin or sorbitol monooleate, and conventional thickening agents. The liquid compositions may be encapsulated in, for example, gelatin capsules.
As topically administered pharmaceutical compositions, the compounds of the present invention may be administered in the form of ointments or creams containing from about 0.1% to about 10% by weight of the active component in a pharmaceutical ointment or cream base.
Compounds of the present invention may be rectally administered in the form of suppositories. For preparing suppositories, a low-melting wax such as a mixture of fatty acid glycerides or cocoa butter is first melted and the active ingredient is dispersed homogeneously in the melt. The mixture is then poured into convenient sized molds and allowed to cool and solidify.
Preferably, the pharmaceutical compositions of this invention are in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate amounts of the active component. The unit dosage can be a packaged preparation with the package containing discrete quantities of the preparation. For example, the package may take the form of packaged tablets, capsules, and powders in envelopes, vials, or ampoules. The unit dosage form can also be a capsule, cachet, or tablet itself or can be the appropriate number of any of these packaged forms.
The quantity of active compound in the unit dosage form may be varied or adjusted from about 0.5 mg to about 350 mg according to the particular application and the potency of the active ingredient.
When employed systematically in therapeutic use as analgesic agents in the pharmaceutical method of this invention, the compounds are administered at doses of from about 0.05 mg to about 2.0 mg of active compound per kilogram of body weight of the recipient.
The rabbit vas deferens is a specific test for activity at the K-receptor and allows comparison of potency and efficacy of a test ligand and its parent K-agonist. Rabbit vas deferens assay (Oka T., Negiski K., et al., Eur. J. Pharmscol., 1981;73:235) was used to test the compounds of the invention. One of the compounds of the invention, the compound of Example 4, 2,3-Diphenyl-cycloprop-2-enecarboxylic acid methyl-(7-pyrrolidin-1-yl-1-oxa-spiro[4.5]dec-8-yl)-amide, exhibited agonist functional activity of EC 50 (LVD)=12 nM.
Example 14 has a carboxylic acid moiety that is likely to confer peripherally active properties to such compounds. The advantage of a peripherally selective K-agonist is that it should be free of CNS-mediated effects on mood, cognition, and motor function but still retain analgesic properties against inflammatory pain of peripheral origin. Hence both centrally acting and peripherally selective actions contribute an embodiment of this invention.
The following specific preparative examples are provided to enable one skilled in the art to practice the present invention. These examples are not to be read as limiting the scope of the invention as defined by the appended claims, but merely as illustrative thereof.
EXAMPLE 1 ##STR3##
Ethyl 2,3-diphenyl-cycloprop-2-ene-1-carboxylate
Ethyl diazoacetate (0.6 cm 3 , 5.7 mmol) in dichloromethane (5 cm 3 ) was added dropwise to a solution of diphenylacetylene in dichloromethane (9 cm 3 ), containing a catalytic quantity of rhodium acetate dimer, at 45° C. under nitrogen. Upon completion of addition, the mixture was cooled to room temperature and the solvent evaporated. The residue was chromatographed (SiO 2 , 20% dichloromethane in heptane to elute unreacted diphenylacetylene followed by 1:1 dichloromethane/heptane) to separate the cyclopropene ester 0.26 g, 15%.
R f =0.39 (SiO 2 , 2:1 heptane/ethyl acetate). υ max /cm -1 2980 (C--H) and 1723 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.70-7.68 (4H, m), 7.50-7.46 (4H, m), 7.41-7.37 (2H, m), 4.20 (2H, q, J=7.2, OCH 2 CH 3 ), 2.82 (H, s, CHCO 2 ), and 1.24 (3H, t, J=7.2, OCH 2 CH 3 ).
EXAMPLE 2 ##STR4##
2,3-Diphenyl-cycloprop-2-ene-1-carboxylic acid
Ethyl 2,3-diphenyl-cycloprop-2-ene-1-carboxylate (1.75 g, 6.6 mol) and potassium hydroxide (1.79 g, 31.9 mmol) were dissolved in methanol (60 cm 3 ) and heated to reflux for 5 hours. The mixture was cooled to room temperature and the solvent evaporated. The residue was partitioned between water (30 cm 3 ) and ethyl acetate (30 cm 3 ). The aqueous layer was separated and washed with ethyl acetate (2×30 cm 3 ) before being acidified to pH=1 with dilute hydrochloric acid and extracted with dichloromethane (3×40 cm 3 ). The combined dichloromethane extracts were dried (MgSO 4 ) and evaporated to give the cyclopropene acid 1.22 g, 78%.
υ max /cm -1 1687 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.72-7.69 (4H, m), 7.51-7.42 (4H, m), 7.39-7.35 (2H, m), and 2.83 (H, s, CHCO 2 ).
EXAMPLE 3 ##STR5##
2,3-Diphenyl-cycloprop-2-ene-1-carboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide
2,3-Diphenyl-cycloprop-2-ene-1-carboxylic acid (0.34 g, 1.44 mmol) was dissolved in chloroform (6.0 cm 3 ). Thionyl chloride (0.42 cm 3 , 5.80 mmol) was added and the mixture stirred at room temperature for 2 days. The mixture was evaporated to dryness and the residue examined by IR, which showed υ max at 1770 cm -1 , indicating that the carboxylic acid group had been completely converted to an acid chloride. The crude acid chloride was dissolved in dichloromethane (3 cm 3 ) and added dropwise to a solution of trans N-methyl-N-2-(1-pyrrolidinyl)cyclohexylamine (0.26 g, 1.44 mmol) in dichloromethane (4 cm 3 ) cooled in an ice bath under nitrogen. The mixture was stirred at room temperature for 30 minutes and then evaporated to give the amine hydrochloride 0.27 g, 43%; mp 175-178° C. (from ether-dichloromethane).
υ max /cm -1 1631 (C═O). Analysis for C 27 H 32 N 2 O.HCl.H 2 O: Requires: C, 71.29; H, 7.70; N, 6.16. Found: C, 71.54; H, 7.56; N, 6.23. 1 HNMR (400 mHz, CDCl 3 ): 7.87-7.85 (2H, m), 7.64-7.62 (2H, m), 7.48-7.43 (4H, m), 7.38-7.34 (2H, m), 3.80 (H, br s), 2.26-2.23 (H, m), 2.18-2.00 (2H, br m), 1.85-1.56 (7H, m), 1.58-1.54 (H, m), and 1.38-1.22 (2H, m).
100% by HPLC; retention time=16.97 minutes (10% to 80% MeCN in H 2 O+1% TFA over 20 minutes).
EXAMPLE 4 ##STR6##
2,3-Diphenyl-cycloprop-2-ene-1-carboxylic acid methyl-(7-pyrrolidin-1-yl-1-oxa-spiro[4.5]dec-8-yl)-amide
2,3-Diphenyl-cycloprop-2-ene-1-carboxylic acid (1.22 g, 5.17 mmol) was dissolved in dichloromethane (20 cm 3 ). Thionyl chloride (1.50 cm 3 , 20.68 mmol) was added and the mixture stirred at room temperature for 2 days. The mixture was evaporated to dryness and the residue examined by IR, which showed υ max at 1769 c -1 , indicating that the carboxylic acid group had been completely converted to an acid chloride. The crude acid chloride was dissolved in dichloromethane (15 cm 3 ) and added dropwise to a solution of N-methyl-7-(1-pyrrolidinyl)-1-oxa-spiro[4.5]decanamine (1.40 g, 5.17 mmol) in dichloromethane (10 cm 3 ) cooled in an ice bath under N 2 . The mixture was stirred at room temperature for 30 minutes and then evaporated to give the amine hydrochloride. It was washed with ether, stirred with ethanolic ammonia (10 cm 3 ) for 30 minutes and then evaporated. The residue was chromatographed (SiO 2 , 1% to 5% methanol in dichloromethane) to separate the major UV-active component (R f =0.53 [SiO 2 , 10% methanol in dichloromethane]) which was dissolved in methanol (5 cm 3 ) and hydrogen chloride (1.0 cm 3 of a 4.0 mol dm -3 solution in dioxane) added. The mixture was stirred for 10 minutes at room temperature, evaporated, washed with ether, and dried in vacuo to give the amine hydrochloride 0.15 g, 6%;
mp 148-150° C. υ max /cm -1 1634 (C═O). Analysis for C 30 H 36 N 2 O 2 .(HCl) 2 .H 2 O: Requires: C, 70.51; H, 7.64; N, 5.48. Found: C, 70.20; H, 7.50; N, 5.35. 1 HNMR (400 mHz, CDCl 3 ): 7.86-7.46 (2H, m), 7.64-7.63 (2H, m), 7.48-7.43 (4H, m), 7.38-7.34 (2H, m), 3.85-3.82 (2H, m, OCH 2 ), 3.57 (3H, br s, NCH 3 ), 3.19 (H, s, CHCO), 3.00 (H, br s), 2.80 (H, br s), and 2.13-1.64 (18H, m).
100% by HPLC; retention time=15.52 minutes (20% to 80% MeCN in H 2 O+1% TFA over 20 minutes).
EXAMPLE 5 ##STR7##
Ethyl 2-(3-chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylate
Ethyl diazoacetate (0.2 cm 3 , 1.9 mmol) in dichloromethane (8 cm 3 ) was added dropwise to a solution of 1-(3-chlorophenyl)-2-phenylacetylene (1.7 g, 8.0 mmol) in dichloromethane (3 cm 3 ) containing a catalytic quantity of rhodium acetate dimer at 40° C. under nitrogen. Upon completion of addition, the mixture was heated at 40° C. for a further 15 minutes, then cooled to room temperature and the solvent evaporated. The residue was chromatographed (SiO 2 , 5% dichloromethane in heptane to elute unreacted acetylene followed by 25% dichloromethane in heptane) to separate the cyclopropene ester. The unreacted acetylene was recycled, using further portions of ethyl diazoacetate (each 1.9 mmol) to give (after four repetitions) the cyclopropene ester 0.55 g, 24%.
R f =0.33 (SiO 2 , 6:1 heptane/dichloromethane). υ max /cm -1 1728 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.68-7.64 (3H, m), 7.57-7.55 (H, m), 7.50-7.47 (2H, m), 7.43-7.37 (3H, m), 4.18 (2H, q, J=7.2, OCH 2 CH 3 ), 2.82 (H, s, CHCO 2 ), and 1.55 (3H, t, J=7.2, OCH 2 CH 3 ).
EXAMPLE 6 ##STR8##
2-(3-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid
Ethyl 2-(3-chloro-phenyl)-3-phenyl-cycloprop-2-ene-1-carboxylate (0.55 g, 1.84 mmol) and potassium hydroxide (0.5 g, 9.25 mmol) were dissolved in methanol (20 cm 3 ) and heated to reflux for 2 hours. The mixture was cooled to room temperature and the solvent evaporated. The residue was partitioned between water (30 cm 3 ) and ethyl acetate (30 cm 3 ). The aqueous layer was separated and washed with ethyl acetate (2×30 cm 3 ) before being acidified to pH=1 with dilute hydrochloric acid and extracted with dichloromethane (3×40 cm 3 ). The combined dichloromethane extracts were dried (MgSO 4 ), evaporated, and washed with heptane to give the cyclopropene acid 0.21 g, 42%.
υ max /cm -1 1680 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.70-7.65 (3H, m), 7.58-7.56 (H, m), 7.52-7.49 (2H, m), 7.44-7.36 (3H, m), and 2.82 (H, s, CHCO 2 ).
EXAMPLE 7 ##STR9##
2-(3-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide
2-(3-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid (0.2 g, 0.74 mmol) was dissolved in chloroform (3 cm 3 ). Thionyl chloride (0.28 cm 3 , 3.80 mmol) was added and the mixture stirred at room temperature for 2 days. The mixture was evaporated to dryness and the residue examined by IR, which showed υ max at 1770 cm -1 , indicating that the carboxylic acid group had been completely converted to an acid chloride. The crude acid chloride was dissolved in dichloromethane (2 cm 3 ) and added dropwise to a solution of N-methyl-N-2-(1-pyrrolidinyl)-cyclohexylamine (0.14 g, 0.74 mmol) in dichloromethane (3 cm 3 ) cooled in an ice bath under N 2 . The mixture was stirred at room temperature for 30 minutes and then evaporated to give the amine hydrochloride 0.065 g, 14%; mp 247-249° C. (from ether-dichloromethane).
υ max /cm -1 1634 (C═O). Analysis for C 27 H 31 CIN 2 O.HCl.(H 2 O) 1 .5 : Requires: C, 65.00; H, 7.03; N, 5.62. Found: C, 64.77; H, 6.56; N, 5.57. 1 HNMR (400 mHz, CDCl 3 ): 7.86 (2H, br s), 7.62-7.59 (2H, m), 7.54-7.31 (5H, m), 3.86 (H, br s), 3.55 (4H, br s, NCH 3 +CH), 3.26 (H, s, CHCO), 3.15 (H, br s), 2.84 (H, br s), 2.24-2.08 (3H, br m), 1.96-1.44 (9H, m), and 1.40-1.26 (2H, m).
100% by HPLC; retention time=18.04 minutes (20% to 80% MeCN in H 2 O+1% TFA over 20 minutes).
EXAMPLE 8 ##STR10##
Ethyl 2-(4-chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylate
Ethyl diazoacetate (0.34 cm 3 , 3.3 mmol) in dichloromethane (7 cm 3 ) was added dropwise to a solution of 1-(4-chlorophenyl)-2-phenylacetylene (2.76 g, 13.0 mmol) in dichloromethane (4 cm 3 ) containing a catalytic quantity of rhodium acetate dimer at 40° C. under nitrogen. Upon completion of addition, the mixture was heated at 40° C. for a further 15 minutes, then cooled to room temperature and the solvent evaporated. The residue was chromatographed (SiO 2 , 7% dichloromethane in heptane to elute unreacted acetylene followed by 1:1 dichloromethane/heptane) to separate the cyclopropene ester. The unreacted acetylene was recycled, using further portions of ethyl diazoacetate (each 3.3 mmol) to give (after three repetitions) the cyclopropene ester 0.66 g, 22%.
R f =0.33 (SiO 2 , 6:1 heptane/ethyl acetate). υ max cm -1 1728 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.65 (2H, dd, J=1.2 and 8.4), 7.59 (2H, dd, J=2.0 and 6.4), 7.49 (5H, m), 4.19 (2H, q, J=7.2, OCH 2 CH 3 ), 2.81 (H, s, CHCO 2 ), and 1.24 (3H, t, J=7.2, OCH 2 CH 3 ).
EXAMPLE 9 ##STR11##
2-(4-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid
Ethyl 2-(4-chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylate (0.66 g, 2.20 mmol) and potassium hydroxide (0.7 g, 12.95 mmol) were dissolved in methanol (25 cm 3 ) and heated to reflux for 2 hours. The mixture was cooled to room temperature and the solvent evaporated. The residue was partitioned between water (30 cm 3 ) and ethyl acetate (30 cm 3 ). The aqueous layer was separated and washed with ethyl acetate (2×30 cm 3 ) before being acidified to pH=1 with dilute hydrochloric acid and extracted with dichloromethane (3×40 cm 3 ). The combined dichloromethane extracts were dried (MgSO 4 ), evaporated and washed with heptane to give the cyclopropene acid 0.27 g, 45%.
υ max /cm -1 1678 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.69 (2H, m), 7.63-7.60 (2H, m), 7.52-7.40 (5H, m), and 2.81 (H, s, CHCO 2 ).
EXAMPLE 10 ##STR12##
2-(4-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid methyl-(2-pyrrolidin-1-yl-cyclohexyl)-amide
2-(4-Chlorophenyl)-3-phenyl-cycloprop-2-ene-1-carboxylic acid (0.25 g, 0.92 mmol) was dissolved in chloroform (3.0 cm 3 ). Thionyl chloride (0.28 cm 3 , 3.80 mmol) was added and the mixture stirred at room temperature for 2 days. The mixture was evaporated to dryness and the residue examined by IR, which showed υ max at 1770 cm -1 , indicating that the carboxylic acid group had been completely converted to an acid chloride. The crude acid chloride was dissolved in dichloromethane (2 cm 3 ) and added dropwise to a solution of N-methyl-N-2-(1-pyrrolidinyl)-cyclohexylamine (0.17 g, 0.92 mmol) in dichloromethane (4 cm 3 ) cooled in an ice bath under nitrogen. The mixture was stirred at room temperature for 30 minutes and then evaporated to give the amine hydrochloride 0.145 g, 33%; mp 252-254° C. (from ether-dichloromethane).
υ max /cm -1 1634 (C═O). Analysis for C 27 H 31 CIN 2 O.HCl.(H 2 O) 0 .25 : Requires: C, 68.14; H, 6.83; N, 5.89. Found: C, 68.12; H, 6.81; N, 5.90. 1 HNMR (400 mHz, CDCl 3 ): 8.99-7.92 (2H, br m), 7.60-7.58 (2H, m), 7.46-7.38 (4H, m), 7.36-7.34 (H, m), 3.90 (H, br s), 3.54 (3H, s, NCH 3 ), 3.25 (H, s, CHCO), 3.02 (H, br s), 2.86 (H, br s), 2.17-2.00 (3H, m), and 1.88-1.28 (12H, m). 100% by HPLC; retention time=18.03 minutes (20% to 80% MeCN in H 2 O+1% TFA over 20 minutes).
EXAMPLE 11 ##STR13##
Dimethyl 2,3-diphenyl-cycloprop-2-ene-1,1-dicarboxylate
A mixture of diphenylacetylene (12.4 g, 69.7 mmol) and catalytic copper (II) acetylacetonate was heated to 145° C. under nitrogen. Diazodimethylmalonate (2.2 g, 13.9 mmol) was added dropwise. The mixture was heated at 145° C. for a further 30 minutes after completion of addition. It was cooled to room temperature and chromatographed (SiO 2 , 20% dichloromethane in heptane to elute unreacted diphenylacetylene followed by 1:1 dichloromethane/heptane) to give the cyclopropene diester 0.63 g, 15%.
R f =0.59 (SiO 2 , 1:1 heptane/ethyl acetate). υ max /cm -1 1755 (C═O). 1 HNMR (400 mHz, CDCl 3 ): 7.78-7.73 (4H, m), 7.52-7.41 (6H, m), and 3.73 (6H, s, OCH 3 ).
EXAMPLE 12 ##STR14##
Methyl 2,3-diphenyl-cycloprop-2-ene-1-carboxylate-1-carboxylic acid
Dimethyl 2,3-diphenyl-cycloprop-2-ene-1,1-dicarboxylate (0.61 g, 2.00 mmol) and lithium hydroxide (0.082 g, 2.00 mmol) were dissolved in a mixture of methanol (10 cm ) and dichloromethane (6 cm 3 ). The mixture was heated to reflux for 2 hours, cooled to room temperature, and the solvents evaporated. The residue was partitioned between water (20 cm 3 ) and ethyl acetate (20 cm 3 ). The aqueous layer was separated and washed with ethyl acetate (2×20 cm 3 ) before being acidified to pH=1 with dilute hydrochloric acid and extracted with dichloromethane (3×25 cm 3 ). The combined dichloromethane extracts were dried (MgSO 4 ), evaporated, and chromatographed (SiO 2 , dichloromethane followed by 1% methanol in dichloromethane) to give the cyclopropene monoacid 0.22 g, 58%.
R f =0.17 (SiO 2 , 1:1 heptane/ethyl acetate). υ max /cm -1 1732 (C═O ester) and 1694 (C═O acid). 1 HNMR (400 mHz, CDCl 3 ): 7.64-7.61 (4H, m), 7.53-7.43 (6H, m), and 3.71 (3H, s, OCH 3 ).
EXAMPLE 13 ##STR15##
1-[Methyl-(2-pyrrolidin-1-yl-cyclohexyl)-carbamoyl]-2,3-diphenyl-cycloprop-2-enecarboxylic acid methyl ester
Methyl 2,3-diphenyl-cycloprop-2-ene-1-carboxylate-1-carboxylic acid (0.21 g, 0.71 mmol) was dissolved in chloroform (4.0 cm 3 ). Thionyl chloride (0.21 cm 3 , 2.85 mmol) was added and the mixture stirred at room temperature for 2 days. The mixture was evaporated to dryness and the residue examined by IR, which showed ν max at 1778 and 1733 cm -1 , indicating that the carboxylic acid group had been completely converted to an acid chloride. The crude acid chloride was dissolved in dichloromethane (2 cm 3 ) and added dropwise to a solution of N-methyl-N-2-(1-pyrrolidinyl)-cyclohexylamine (0.13 g, 0.71 mmol) in dichloromethane (3 cm 3 ) cooled in an ice bath under nitrogen. The mixture was stirred at room temperature for 30 minutes and then evaporated to dryness. The residue was dissolved in ethanolic ammonia for 30 minutes at room temperature and the solvent evaporated. The residue was partitioned between water (10 cm 3 ) and dichloromethane (10 cm 3 ). The organic layer was washed with water (3×10 cm 3 ), dried, and evaporated to give the amine. Half the material was chromatographed (SiO 2 , 5% methanol in dichloromethane) to separate the major UV-active component (R f =0.42 [SiO 2 , 10% methanol in dichloromethane]). It was dissolved in methanol (2.0 cm 3 ), hydrogen chloride (1.0 cm 3 of a 4.0 mol dn -3 solution in dioxane) was added, and the mixture was stirred at room temperature for 30 minutes. The solvents were evaporated and the residue washed with ether and dried in vacuo to give the amine hydrochloride 0.097 g, 53%; mp 112-114° C.
υ max /cm -1 1716 (OC═O) and 1634 (NC═O). Analysis for C 29 H 34 N 2 O 3 .HCl.H 2 O: Requires: C, 65.60; H, 7.35; N, 5.28. Found: C, 65.45; H, 7.24; N, 5.18. 1 HNMR (400 mHz, CDCl 3 ): 7.76-7.70 (4H, m), 6.52-7.43 (6H, m), 3.96 (H, br s), 3.73 (3H, s, OCH 3 ), 3.60 (H, br s), 3.50 (H, br s), 3.36 (3H, s, NCH 3 ), 2.88 (H, br s), 2.74 (H, br s), 2.37 (H, br s), 1.96-1.52 (9H, m), and 1.37-1.20 (3H, m). 100% by HPLC; retention time=18.69 minutes (20% to 80% MeCN in H 2 O+1% TFA over 20 minutes).
EXAMPLE 14 ##STR16##
1-[Methyl-(2-pyrrolidin-1-yl-cyclohexyl)-carbamoyl]-2,3-diphenyl-cycloprop-2-enecarboxylic acid
A solution of 1-[methyl-(2-pyrrolidin-1-yl-cyclohexyl)-carbamoyl]-2,3-diphenyl-cycloprop-2-enecarboxylic acid methyl ester (0.64 g, 1.26 mmol) in dichloromethane (3 cm 3 ) was added to lithium hydroxide monohydrate (0.265 g, 6.3 mmol) in a mixture of methanol (9 cm 3 ) and water (6 cm 3 ). The mixture was heated to reflux overnight. After cooling to room temperature, the solvents were evaporated and the residue partitioned between water (20 cm 3 ) and dichloromethane (20 cm 3 ). The organics were extracted with aqueous sodium hydroxide (20 cm 3 ) and the combined organics washed with dichloromethane (20 cm 3 ) before being acidified to pH=1 with dilute hydrochloric acid and extracted with dichloromethane (3×40 cm 3 ). The combined acidic extracts were dried, evaporated, and chromatographed (SiO 2 , 5% to 10% methanol in dichloromethane) to separate the amino acid hydrochloride 0.17 g, 26%; mp 187-189° C.
υ max /cm -1 2940 (C--H), 1634 (NC═O), and 2594 (OC═O). R f =0.22 (SiO 2 , 10% methanol in dichloromethane). Analysis for C 28 H 32 N 2 O 3 .(HCl) 1 .5.H 2 O: Requires: C, 65.02; H, 6.87; N, 5.42. Found: C, 65.09; H, 6.69; N, 5.20. 1 HNMR (400 mHz, CDCl 3 ): 7.94-7.45 (4H, m), 7.44-7.23 (6H, m), 4.70 (H, br s), 3.50-3.00 (5H, br s), 3.15 (3H, s, NCH 3 ), 1.87-1.66 (8H, m), and 1.33-1.19 (4H, m).
99% by HPLC; retention time=14.67 minutes (20% to 80% MeCN in H 2 O+1% TFA over 20 minutes). | The diphenyl-cyclopropene derivatives of the instant invention are kappa opioids useful in the treatment of pain, inflammation, Parkinsonism, dystonia, cerebral ischemia, diuresis, asthma, psoriasis, irritable bowel syndrome, and stroke.
The compounds are K-agonists which are centrally acting and peripherally selective acting. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates to a biological hard tissue inductive scaffold material composed of titanium or titanium group alloy fiber which is used together with an implant such as an artificial root of the tooth or an artificial joint implant, a method for preparation thereof and a cell culture proliferation reactor in regenerative medicine engineering.
DESCRIPTION OF THE PRIOR ART
[0002] In general, in the field of oral surgery or orthopaedic surgery, as a material for implant to be implanted in an organism, a product made of metallic material such as an artificial root of the tooth or an artificial joint are conventionally used. Recently, among these metallic materials, the uses of titanium and titanium alloy are remarkably becoming frequent. The reason is that, in comparison with other metals, titanium has an excellent properties including rare antigenic function in an organism, relatively small specific gravity and strong mechanical strength. Further, at the MRI examination of a patient to whom a metallic material is implanted, if the metallic material has magnetic property, various problems cause. On the contrary, titanium which does not have magnetic property, is superior at this subsidiary effect, and this is one of the reason why titanium is admirably used.
[0003] In particular, the uses of a medical material composed of titanium or titanium group alloy are broadly increasing in the field of orthopaedic surgery or dentistry. Accordingly, metallic material which does not have antigenic function acts good function in an organism, and contributes to the improvement of QOL of a postoperative patient.
[0004] However, the medical material composed of titanium or titanium group alloy is not sufficiently satisfied. For example, even if there is no antigenic function, at a contact surface of a titanium metallic material with an organism, in some occasions, sheath tissue is formed by gathering fibroblasts of connective tissues with collagenous fiber on the surface of material even if it is implanted in a bone tissue. Therefore, when a titanium metal material can not contact directly with a bone tissue, there is a problem that it is difficult for the bone tissue and the metallic material to become an one body.
[0005] To dissolve this problem, recently, improvement by coating hydroxy apatite on the surface of titanium is carried out, while improvement to have complicated structure on the surface by forming a structure considering an inductivity and stickiness of bone tissue, that is, forming convex and concave structure on the surface of the material or to stick many fine beads on the surface are carried out. However, by these means, the biological and mechanical bonding of the metal material with bone tissue is not sufficient. Even if the metal material and bone tissue can be observed to be bonded, when a breaking starts from a marginal part, the breaking can not be restored and extends to whole part, causes loosening and falls down in early stage. These instances are becoming clear by repeating many cases. Therefore, in cases of aged patients, very dangerous phenomena that the dissociation between the material and bone tissue progresses gradually are frequently observed. Further, since it is necessary to progress 3 to 6 months to complete the bonding of the metallic material with bone tissue, a problem that the next step treatment can not be started is actually pointed out.
[0006] For dissolution of above problem, recently, together use of BMP (Bone Morphogenetic Protein) which accelerate the induction of osteoblasts or BMP relating to the induction of other cells with medical materials e.g. implant made of titanium is carried out. Together use with these physiological functional activators is effective, and migration of osteoblasts can be observed closely to the titanium metallic material, however, the formation of cells of tissue status called as osteointegration characterizing that material and bone are becoming one body can not easily be observed.
[0007] In the meanwhile, as the aforementioned improved technique for trial to make the surface of material complicated shape, the following method is proposed. That is, the technique to wind up at random and accumulate fine fibers made of titanium or titanium alloy surround the core part of implant to be implanted into vivo bone, to form a compressed body of desired shape and dimension by compressing to the core direction and to prepare a dentistry implant made of titanium having buffering function by combining the body with the core are proposed (Japanese Application Publication H8-140996). As the specific example of fine fibers, fine fibers having 0.1 mm to 0.7 mm diameter, desirably fine fibers having 0.3 mm to 0.5 mm diameter are indicated. The meaning of “body” formed by the titanium fibers is to perform a buffering function by accepting outer strength, namely occusal strength, elastically to the all direction, further to accept the migration and proliferation of vivo bone tissue from many pore gaps so as to improve the stickiness to the bone of the implanted part and to assume better stability of the implanted part.
[0008] Furthermore, a process to produce “pore structure” by pouring a mixture of metal and an foaming agent in a mold, heating to the temperature higher than melting point under pressing condition and by releasing the pressure air at adequate period (U.S. Pat. No. 2,553,016), and as developing embodiment of this process, a process to generate the mercury vapor or to generate a specific gas by decomposition of hydroxide or carbide of titanium or zircon (U.S. Pat. No. 2,434,775 and U.S. Pat. No. 2,553,016) are proposed. And an orthopaedic implant which attempts to combine bone tissue and an implant by obtaining thin layer of metal “pore structure” by specific foaming methods characterizing to generate pores at the melting state of metal which are mentioned above, adhering said thin layer to the surface of the implant and inducing bone tissue into pore cells after implanted into organism is proposed (Japanese Application Publication H11-341). As an example of metal used in above processes, various metals such as pure titanium, titanium alloy, stainless steel, cobalt-chrome alloy or aluminium are disclosed. And, also disclosed that the size of opening formed by pore is in the limitation of 0.5 mm to 1.5 mm, further that the “pore structure” is to be formed by thin layer of 1.5 mm to 3 mm thickness.
[0009] The former proposal is basically to prepare one titanium filament of 0.1 mm to 0.7 mm diameter, to wind it up around the implant core, and to compress so as to form porous gaps which permit migration and proliferation of neogenesis bone tissue between accumulated filaments. However, it is obvious that there is a limit for the formation of the porous gaps. That is, this method is to wind up the fiber material and to compress the fiber material in the core direction so as to equip the fiber material to the core, and the possibility to adjust porous gaps is small. If the fiber material is wound not so tightly aiming to secure certain gaps, the problem that the equipping of the fiber material to the core becomes difficult occurs. Namely, since there is a limitation to attempt migration and proliferation of bone tissue by above mentioned method, sufficient osteointegration tissue is not formed.
[0010] Further, regarding the latter proposal, since the “pore structure” is controlled by “amount of gas and shape” to be supplied to melted metal, it can not be said that the controlling of the size of cell, distribution of pores and thickness of wall which have influence directly to migration, adhesion and proliferation of osteoblasts is not so easy. The size of opening formed by pore disclosed in the proposal is in the limitation of 0.5 mm to 1.5 mm, and the thickness of wall of cell can be presumed from the scale of attached drawing as same as to the size of opening formed by pore or more. This thickness of wall of cell is not so remarkably different from that of the fine beads method based on the diameter of fine beads which is a prerequisite art of this proposal, therefore, it is difficult to expect good affinity with bone cells so as to bring formation of one body with tissue.
[0011] As mentioned above, in the previous methods that use titanium or titanium group alloy, which are recognized to have good affinity with organism tissue, there are several problems in aforementioned points, in particular, the formation of sufficient tissue in which bone tissue and titanium material become one body, namely so called osteointegration is not accomplished. After operation, loosening of bond between bone and titanium occurs from a marginal part, and in many cases the loosening is led to falling down of a tooth in early stage. A patient is feeling discomfort during the process before the falling becomes inevitable. That is, many problems are pointed out. In the cases of conventional artificial root of the tooth or artificial joint which are actually used in medical field, the bond of bone with metal is plane as shown in FIG. 1 (A) and it needs from 3 months to 6 months to accomplish enough bonding strength, therefore it is necessary to keep rest during this period and is impossible to progress to the next step. This point will be illustrated in the drawing mentioned later. The reason responding to said problem can be explained as follows, that is, the field in which cells act to accomplish the bond with metal is only two dimetional plane formed between planes of each subject to be bonded and can be said as a simple and minimized plane.
[0012] As mentioned above, the conventional methods of using such as titanium metal material are aiming to bond bone tissue with an implant made of metal by two dimensional plane, and said conventional arts called it as osteointegration. However, from the biological viewpoint, there is a problem of preservation for long term. The object of the present invention is to provide a biological hard tissue inductive scaffold material which can induce the tissue layer of hybrid state by three dimensionally cooperating an implant material with bone tissue of organism side by using an implant to be replaced to various hard tissues which do not have above problems.
[0013] Further the object of the present invention is to provide a method to accomplish the bonding of a metal material with bone within one month, in contrast to the conventional method which takes 3 to 6 months to accomplish the bonding of a metal material with bone. This is proved in Example 3 mentioned later.
[0014] Furthermore, in the regenerative medicine engineering of today, it is actually required to carry out the trial to prompt the rapid proliferation of active cells including bone cells by introducing osteoblasts or stem cells with a physiological active material to the replacing material for hard tissues. That is, a material which can be used as a bioreactor for cell cultivation, which is characterized that the physiological active material or stem cells can be surely kept for a certain period, timed-releasability can be displayed and having good affinity to cells is required. Said bioreactor with the cells can be implanted in tissue of a human body as a whole, the proliferated cells are separated and can be supplied to a researching facility where the proliferated tissue is needed or to a medical facility immediately. To said requirement, the conventional material is not the material which can satisfy the requirement sufficiently.
SUMMARY OF THE INVENTION
[0015] The present invention is to develop and to provide a material which can respond to the above mentioned requirement, that is, can be used as the scaffold material effective to a biological hard tissue, further, can be used as a bioreactor effective to cells besides the hard tissue.
[0016] The inventors of the present invention have carried out intensive study as illustrated below, and have made it clear that osteoblasts can be easily migrated to fine fibrous material of titanium metal and proliferates, that is, has good affinity with it, and there is high correlation between diameter of fiber to be used and proliferation action of cells, and have obtained a series of important knowledge based on the knowledge, and have developed and proposed the material which can respond to said requirement.
[0017] That is, the inventors of the present invention have investigated intently about the cultivation condition which osteoblast like, and have made it clear that osteoblast grows in geometric space composed by very fine fibers. By continuing further basic investigation, the inventors of the present invention have obtain the following knowledge, that is, osteoblast indicates very high affinity to titanium fiber, and specifically, in the geometric space composed by a mass of titanium fiber having smaller diameter than 100 μm and extend of it is from 100 to 400 μm indicates higher affinity and have a specific property to stick more actively than that of titanium fiber having larger diameter than 100 μm.
[0018] A part of medical results of these series of knowledge were already reported in “Densitry in Japan” vol. 37, page 42-50, 2001, “J. Bone and joint surgery” 93A, S1-105 to 115, 2001, “J. Biochemistry”, Vol. 121, page 317 to 324, 1997 (not all results as disclosed in the present invention, and the method for dissolving of the problem is not reported).
[0019] The inventors of the present invention have expanded the property of fiber actively obtained from above mentioned knowledge and from the view point that the one body tissue of hybrid state composed of bone tissue, metal fiber and an implant can be induced by arranging the fibers surrounding the metal implant, have repeated various experiments and have made it clear that the aimed result can be obtained.
[0020] As aforementioned, in the cases of an artificial root of the tooth or an artificial joint, since the bonding of bone with metal is plane, it takes from 3 to 6 months to accomplish a bonding tissue with sufficient strength and it is necessary to keep rest during this period and is impossible to progress to the next step. However, by the present invention, the three dimensional complicated space formed by titanium fibers is provided, namely in the case of a layer of 2 mm thickness, the surface area is more than 20 times larger than that of plane, consequently the space where cells can act is provided, and it become clear that osteointegration of bone tissue can be accomplished in short period together with the acceleration effect of action of cells.
[0021] Further, by the continuation of investigation, it becomes clear that the induction and proliferation of cells can be possible on other cells besides osteoblasts. That is, when the titanium fiber having smaller diameter than 100 μm, it is understood that various kind of cells are induced into fiber layer and stick actively and grow. That is, the inventors of the present invention have succeeded to provide a medical material composed of metal implant material having high affinity to whole tissue of organism by use of the fine titanium fiber.
[0022] Even if the hybrid with an implant is formed by inducing cells into fiber layer utilizing high affinity of cells to titanium fiber layer composed of titanium fiber having said specific diameter, the morphological stability is required when it is used by implanting into human body. The inventors of the present invention have investigated this point and have accomplished the following process. That is, the titanium fibers are accumulated at random and form a layer, then is sintered by alone or by winding up to an implant in vacuum condition. The cross points of fibers each other and contacting points of the fibers with the implant are fused at the spots and forms a rigid structure. The outer strength loaded to the layer is dispersed to many fused points, and forms the subject of rigid structure with good morphological stability having sufficient strength. Further, after fused, it is found that the affinity of bone cells to the tissue of organism is not affected by fusing process at all.
[0023] As the method to stick or fix metal fibers, soldering method or silver soldering method can be mentioned, however, in these methods paste is generally used. And, since the paste has a possibility to contain harmful component to cells, this method can not be said as an adequate method. Aforementioned sintering method in vacuum condition is selected from various fusing and sticking methods considering this point and the effectivity of it is found out. The sintering in vacuum condition does not use harmful subject to cells and does not generate harmful subject to cells. But, if there is another method which is effective to stick fiber each other, that is, there is a fusing method which does not affect the growth of cells, tissue or human body, there is no problem to adopt the method and is contained in the scope of the present invention.
[0024] The inventors of the present invention have carried out more intensive study and found out that bone cells can be more effectively induced by accelerating the implantation of osteoblasts by depositing crystal of hydroxyl apatite or hydroxyl apatite containing apatite carbonate on the surface of fiber of titanium metal layer, or by previously sticking physiological functional activator such as various cytokine e.g. BMP (Bone Morphogenetic Protein) or cell growth factor component which accelerate the growth of osteoblasts. Such function and effect are not provided simply by the function of the treated component, but is provided by together use with fine titanium fibers. Further, it becomes clear that function and effect with remarkable preserving ability and times-releasing ability is provided and generated.
[0025] When said function and effect are compared with that of a plane subject, there is remarkable difference. This difference is considered to be caused by remarkable difference of surface area compared with that of plane subject. That is, even if the loading amount is same, the loading state does not biase and loaded homogeneously to the broad area, further, the loading area is improved and consequently the total loading amount is improved. Further, the function of the physiological active material acts more broadly, because very fine fibers of less than 100 μm diameter is used instead of a plane subject with small surface area, and accordingly induces osteoblasts effectively and can form strong one body tissue of organism.
[0026] As the method for loading of this case, above mentioned BMP component, cytokine, various cell growth factor component or factor having an activity of organism can be stuck directly to the metal fiber. However, it is effective to contain a subject which can be absorbed in organism such as polyglycolic acid, polylactic acid, copolymer of polylactic acid-polyglycolic acid, biodegradable (3-hydroxylbutyl-4-hydroxylbutylate) polyester polymer, polydioxane, polyethyleneglycol, collagen, gelatin, albumin, fibrin, chitosan, chitin, fibroin, cellulose, mucopolysaccharide, vitronectin, fibronectin, laminin, alginic acid, hyaluronic acid, heparin, heparan sulfate, chondroitin sulfate, polyamino acid, dextran, agarose, pectin, mannan and derivatives thereof between fibers of titanium or titanium compound, then to adsorb above mentioned factors to the absorption subjects in organism.
[0027] The inventors of the present invention have clarified that if it is possible to control the behavior of cells, namely, the behavior that the cells can easily adhere to fine fibers, by controlling said bioactive materials, the time and the position to induce and to activate cells can be voluntarily controlled and can be used as one of effective embodiments. Of cause, said behavior of cells can be concluded as the essential property which cells have themselves not by use of said bioactive materials.
[0028] By using the embodiment that fibers are entangled at random, cells migrate positively into gaps between fibers arranged at random, and a strong three dimensional hybrid structure characterizing that cells and metallic fibers are complicatedly entangled is formed. And in the case, when the structure is needed to be reinforced to a specific direction, it is possible to use a woven cloth and it is not to limit the scope of the present invention.
[0029] The case to apply above mentioned metallic fiber layer to a human body or other animal body, for example, if an implant metal material is implanted in bone tissue, cells to generate a blood vessel and a bone into three dimensional gap composed of metallic fiber layer equipped to the implant, generate a hybrid structure and metal material and bone tissue becomes one body, as illustrated above. Accordingly, anchor effect of an implant metal material becomes stronger and the metal material becomes to be fixed strongly in the bone tissue. It becomes clear that for the rapid formation of said anchor effect by invading and fixing of cells and blood vessel, the use having titanium fibers of specific diameter and of specific aspect ratio is necessary and is the unexpected action and effect.
[0030] This knowledge is the result obtained by many actual experiments (several hundred cases), and the investments considering the relationship between diameter of fine fiber of specific metal (titanium or titanium group alloy) and cells is carried out by the inventors of the present invention as the first time and is very creative and novel. And by using the fine fibers, remarkably excellent action and effect are provided, consequently, the present invention contributes largely to the growth of medicine and the welfare of the human beings. The metal material as an implant to which the scaffold material of the present invention is equipped is used in these experiments, is referring to a medical implant made of titanium metal used in medical field because of necessarily to refer the affinity with bone, however, of cause, it can be used for a medical implant made of other metal or non-metallic material.
[0031] Further, the inventors of the present invention have clarified from various experiments that, to the titanium fiber of less than 100 μm diameter, various kinds of cells besides osteoblasts actively acts physiologically same as to osteoblast and possesses a property to adheres positively. Of cause, in which a stem cell which is called as an universal cell is contained. That is, from this fact, the inventors of the present invention have clarified that the titanium metal fiber layer of less than 100 μm diameter has a function for a cell cultivate and proliferation material in regenerative medical engineering, and can be used as a cell culture proliferation reactor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic view and the partial enlarged view of a conventional implant (A) and an implant of the present invention composed of a titanium rod and non-woven cloth of titanium fibers, which was fused to the surface of the rod by vacuum sintering (B).
[0033] FIG. 2 is a comparative microscopic picture of the BMP induced heterotopic bone formation in rat subcutaneously using two materials as the carrier of BMP as the result of active bone formation when a metal rod alone was implanted.
[0034] FIG. 3 is the drawing showing the different in amount of bone formation when the two materials were implanted into rat subcutaneously. “TWTR” indicates that the amount of bone formation when a scaffold of the present invention which composed of metal root and a non-woven cloth of titanium fibers, which was fused on the surface of the rod, was implanted with BMP. “TR” indicates amount of bone formation when a metal rod alone was implanted with BMP. Bone amounts are examined 4 weeks after implantation and expressed by calcium contents.
[0035] FIG. 4 is a comparative microscopic picture of the BMP induced bone formation in rat skin when the two materials as follow were used as BMP carriers. A: s titanium rod simply attached with a non-woven cloth of titanium fibers with apatite coating. B: the same material as A, but without apatite coating. The former shows very active bone formation (bone is clearly distinguished by red color or as thicker and fused contour by gray or black color), but the latter poor. Both materials were examined 4 weeks after implantation.
[0036] FIG. 5 is comparative microscopic picture of the amount of bone formation when the two materials as follow were implanted into the bone defect in the cranium of rabbits. A: a scaffold of the present invention, which composed of titanium rod and a non-woven cloth of titanium fibers, which was fused by vacuum sintering on the rod and then hydroxyapatite coated. B: the same material as A, but without apatite coating on the surface. The former shows active bone formation within the non-woven cloth, but the latter very poor. Both materials were examined 4 weeks after implantation.
[0037] FIG. 6 is a microscopic observation showing state of bone formation when a specimen of a titanium implant, which equipped with titanium beads, was implanted into the defect of rabbit cranium (A), and a state of bone tissue formed by self-healing of the defect (B). Both microscopic pictures were observed after 4 weeks after operation.
[0038] FIG. 7 is a drawing of the results by SEM observation of the surface of titanium fibers sintered with the titanium rod and with apatite coating (A), and the same materials as A, but without sintering on with titanium rod (B). There was no detectable difference between them.
[0039] FIG. 8 is a drawing of the results by SEM observation of the surface of titanium fibers before (A) and after (B) sintering in vacuum. There was no detectable difference between them.
[0040] FIG. 9 is a drawing showing comparative experimental results of osteoblasts proliferation (A) and cytodifferentiation (B) by a bioreactor of present invention (right column), conventional porous apatite (middle column) and on a conventional plastic dishes (left column). Cell numbers were expressed by DNA contents.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0041] Considering abovementioned series of knowledge, the inventors of the present invention have dissolved the problems mentioned above by carrying out subjects recited in (1)-(13).
[0042] (1) A biological hard tissue inductive scaffold material to be used with various implants comprising, titanium or titanium group alloy fiber, wherein said biological hard tissue inductive scaffold material is materially designed to excel in biological hard tissue inductivity and fixing ability, said titanium or titanium group alloy fiber is selecting a fiber whose average diameter is 100 μm or less and aspect ratio is 20 or more, (short axis:long axis ratio=1:20 or more), and said fibers are accumulated to form a layer so as to form an implantation space for biological hard tissue from the surface to inside.
[0043] (2) The biological hard tissue inductive scaffold material of (1), wherein a layer shaped scaffold material comprising said fibers or various implants to be used with said scaffold material are sintered in vacuum so as crossing points or contacting points of the fibers each other or the fibers and the implant to be fused and fixed.
[0044] (3) The biological hard tissue inductive scaffold material of (1) or (2), wherein the surface of said fibers is treated with apatite forming liquid and coated with calcium phosphate compound containing hydroxyapatite or carbonate apatite.
[0045] (4) The biological hard tissue inductive scaffold material in accordance with anyone of (1) to (3), wherein the surface of said fibers is treated with treating liquid containing a physiological active material or a physiological activation promoter which activates cells.
[0046] (5) The biological hard tissue inductive scaffold material of (4), wherein the physiological active material or a physiological activation promoter which activates cells is at least one selected from the group consisting of cell growth factor, cytokine, antibiotic, cell growth controlling factor, enzyme, protein, polysaccharides, phospholipids, lipoprotein or mucopolysaccharides.
[0047] (6) The biological hard tissue inductive scaffold material in accordance with anyone of (1) to (5), wherein the implant is an artificial root of the tooth having an embedding part and the layer which is winded and compressed around the embedding part to integrally fixed to the embedding part.
[0048] (7) The biological hard tissue inductive scaffold material in accordance with anyone of (1) to (5), wherein the implant is an artificial joint having an embedding part and the layer which is winded and compressed around the embedding part to integrally fixed to the embedding part.
[0049] (8) The biological hard tissue inductive scaffold material in accordance with anyone of (1) to (5), wherein the implant is an implant for bone repairing having an embedding part and the layer which is winded and compressed around the embedding part to integrally fixed to the embedding part.
[0050] (9) The biological hard tissue inductive scaffold material in accordance with anyone of (6) to (8), wherein the integral formation of embedding part with the layer is carried out by sintering in vacuum.
[0051] (10) A method for preparation of the biological hard tissue inductive scaffold material comprising, forming a layer by entangling titanium or titanium group alloy fibers whose average diameter is smaller than 100 μm and aspect ratio is 20 or more, winding up the layer to the artificial root of the tooth or an artificial joint, and sintering it in vacuum so as to fuse the crossing points or contacting points of the fibers each other or the fibers and the implant.
[0052] (11) A cell culture proliferation reactor in regenerative medical engineering comprising, using titanium fibers whose average diameter is 100 μm or less and aspect ratio is 20 or more, (short axis:long axis ratio=1:20 or more), or further treated with apatite forming liquid and coated with calcium phosphate compound containing hydroxyapatite or carbonate apatite. And said fibers are accumulated to form a layer so as to create a space for growing of biological hard tissue from the surface to inside, excelling in biological hard tissue inductivity and fixing ability.
[0053] (12) The cell culture proliferation reactor in regenerative medical engineering of (11), wherein the layer of fibers is treated with solution containing a physiological active material or a physiological activation promoter which activates cells.
[0054] (13) The cell culture proliferation reactor in regenerative medical engineering of (11), wherein the physiological active material or a physiological activation promoter which activates cells is at least one selected from the group consisting of cell growth factor, cytokine, antibiotic, cell growth controlling factor, enzyme, protein, polysaccharides, phospholipids, lipoprotein or mucopolysaccharides.
[0055] In the present invention, the wording of “fibers are accumulated to form a layer” means to accumulate woven cloths having network space to form a layer or to accumulate non-woven cloths prepared by entangling fibers to form a layer. And the purpose to create a space for growing of biological hard tissue from the surface to inside and to materially design excelling in biological hard tissue inductivity and fixing ability can be accomplished by the formation of non-woven cloth layer by entangling titanium fibers whose average diameter is 100 μm or less and aspect ratio is 20 or more at random, and space formed by said non-woven cloth has an opening which permits the migrating of cells and the space sufficient for proliferation of the migrated cells. In the Examples mentioned below, said fiber layer is referred using void fraction and density, and biological hard tissue inductivity and fixing ability are effective in very broad range. The present invention can set up excellent space to biological hard tissue by restricting the thickness of fibers to 100 μm or less and excels in processability, therefore is advantageous compared to the case which uses thicker fibers. Additionally, the present invention has a significant meaning at the cell size level technique, besides the difference of apparent thickness.
EXAMPLE
[0056] The embodiments of the present invention are illustrated based on the Examples and drawings disclosed in following heterotopic bone forming experiments, homotopitic bone forming experiments, apatite coating experiments or cell proliferating experiments. These Examples are disclosing specific examples for the easy understanding of the present invention and not intending to limit the scope of the claims of the present invention.
[0057] The scaffold material used in following experiments is the material prepared by the process mentioned below. That is, preparing a layer represented by non-woven cloth formed by entangling titanium metal fibers or titanium group alloy fibers and whose average diameter is 100 μm or less and aspect ratio is 20 or more at random, winding said layer around the outer periphery of a titanium implant material and sintering them in vacuum so as crossing points or contacting points of the fibers each other or the contact points of fibers and the implant to be fused and fixed, then carrying out a treatment of apatite coating. Relationship between a conventional titanium implant and a bone tissue grown around said implant and relationship between a titanium implant around which the scaffold of the present invention composed of titanium fibers layer (non-woven cloth) and a bone tissue grown around said implant are shown respectively in FIG. 1 .
[0058] (A) shows an titanium implant prepared by a conventional method and a bone tissue grown around said titanium implant and bone tissue grown around the implant can be observed (left side drawing), however, from the enlarged drawing (right side drawing) it is understood that bone tissue is only bonded plane to the implant. On the contrary, (B) is the drawing showing the relationship between an implant to which scaffold of the present invention is set up and bone tissue grown around said implant (left side drawing), the bone tissue is induced into a fiber layer in which fibers are entangled three dimensionaliry, bonded with the three dimensional and complicated structure and continued to the outer bone tissue through this bonding layer. That is, compared with (A) by conventional implant, it is clearly understood that the rigid bone tissue structure based on the anchor effect by the complicatedly entangled fibers and the space formed by said complicatedly entangled fibers, that is osteointegration is three dimentionaliry accomplished.
Example 1
[0000] Heterotopic Bone Forming Experiment Under the Skin of Rat
[0059] I. Preparation of a Specimen for Experiment: Following Examples {circle around (1)} and {circle around (2)} are Prepared.
[0060] {circle around (1)} Preparing a non-woven cloth of 85% void fraction and 0.9 g/mL density composed of titanium metal fiber having 8 μm-80 μm diameter and 20 or more aspect ratio (product of Bekinit Co., Ltd.). This non-woven cloth is wounded firmly to a titanium rod by a voluntarily thickness, and a composite consisting of titanium non-woven cloth and a titanium rod of 1.5 mm diameter is prepared. Said composite is filled in a sintering syringe made of ceramics and sintered at 1000° C. for 5 hours in high vacuum condition. Consequently, at many contacting points of fibers themselves and contacting points with titanium rod surface, fibers are fused. And thus the rigid composite which does not sink or does not cause the transformation of shape by adding forth on the surface is prepared.
[0000] {circle around (1)} A titanium metal rod having 1.5 mm diameter.
[0061] II. Method for Implanting Experiment:
[0062] 1. A composite corresponding to the scaffold material of above mentioned specimen {circle around (1)} of the present invention and a metal rod corresponding to the implant in conventional technique of above mentioned specimen {circle around (2)} are respectively implanted with S-300BMP, which is bone forming protein extracted from cow bone and purified, under the skin of a rat and the bone forming experiments for 4 weeks are carried out. After 4 weeks the difference between said two specimens are observed by a microscope histologically and quantitative analysis of Ca stuck to metal rod is carried out.
[0063] III. Experimental Results:
[0064] Results by microscopic observation are shown in FIG. 2 . In the case of a composite specimen {circle around (1)} prepared by sintering a non-woven cloth made of metal titanium in vacuum, which is the scaffold material of the present invention, the state of formation of bone after 4 weeks is shown in FIG. 2 (A). In FIG. 2 (A), osteoblasts are infiltrated and induced into said non-woven cloth and the formation of vigorous bone structure which is complexly complicated is observed. On the contrary, results by titanium metal rod alone, namely, to which non-woven cloth is not wound, is shown in FIG. 2 (B). From FIG. 2 (B), the formation of bone tissue characterizing that said two are becoming three dimensionalily one body is not observed and at the interface of rod (black part) and bone (white part) there is no bonding to connect these two, and the rod and bone are only existing independently holding said interface between.
[0065] Further the results by Ca quantitative analysis are shown in FIG. 3 . That is, in the case specimen {circle around (1)} when titanium non-woven cloth is wound around the titanium rod having 1.5 mm diameter, it becomes clear that 2.3 mg of Ca in average is stuck to one implant. While in the case of specimen {circle around (2)} which does not wound titanium non-woven cloth, the sticking amount is only 0.13 mg, and there is obvious difference between these two, and the difference is almost 18 times.
Example 2
[0000] Experiment to Confirm the Effect of Hydroxyl Apatite Coating Treatment to the Formation of a Heterotopic Bone
[0066] Experimental Method:
[0067] After titanium non-woven cloth is put on a titanium rod having 1.5 mm diameter without sintering in vacuum following two composites are prepared. That is, apatite coated composite {circle around (3)} prepared by a liquid dipping method which is an apatite coating treatment disclosed in Example 4 mentioned later, and non apatite coated composite {circle around (4)} are prepared. These composites are implanted under the skin of rat for 4 weeks and the difference of bone tissue formation between these two composites is compared.
[0068] Experimental Results:
[0069] Results are shown in FIG. 4 . In the apatite coated composite {circle around (3)}, vigorous bone formation is observed at the titanium non-woven cloth part. Bone is clearly distinguished as the red colored areas or as thicker and fused contour in gray or black FIG. 4 (A) . However, since the titanium non-woven cloth is not treated by sintering in vacuum at the surface of the titanium rod, these two are not united in one body and the growth of bone is not observed on the surface of rod, while bone is formed in the fiber space slightly apart from the surface of rod FIG. 4 (A) .
[0070] On the contrary, in non apatite coated composite (4 bone is not formed at all FIG. 4 (B) . That is, from this heterotopic bone forming experiment, it becomes clear that the apatite coating treatment is acting very important role in the formation of bone. Further, the experimental results of the specimen {circle around (1)} characterized that a titanium metal rod and titanium non-woven cloth is fused by sintering in vacuum of Example 1 and of the composite {circle around (3)} characterized that a titanium metal rod and titanium non-woven cloth is not fused by sintering in vacuum of Example 2 clearly indicate that it is important that titanium non-woven cloth is previously fused to a titanium metal rod to form one body by sintering in vacuum. That is, this sintering treatment in vacuum contributes not only to mechanical strength of the composite, but also to the improvement of the effect for bone formation, and acts very important role.
[0071] All experiments described in Examples 1 and 2 are heterotopic bone forming experiment under the skin of rat, and the object of these experiments are to confirm and investigate the significance of equipping with titanium non-woven cloth by bone forming experiments at the tissue except bone, and summarized in Table 1.
TABLE 1 Summary of experiments described in Examples 1 and 2 Composite indication by marks formation of bone Titanim rod (TR) alone TR − TR and titanium TR + TM + or some times − non-woven cloth (TM) TR + TM and apatite TR + TM + HAP + + + Coating (HAP) TR + TM + HAP and TR + TM + HAP + SIN + + + + sintering in vacuum (SIN)
Example 3
[0000] Orthotopic Bone Forming Experiment in Head Bone of Rabbit
[0072] I. Experimental Method
[0000] Experiments are carried out according to the procedures 1, 2 and 3 mentioned below.
[0000]
1. A rabbit of 2.5 kg weight is anesthetized by nenbutal intravenous anesthesia, and perioste of head bone is partially incised and a hole of 3 mm diameter and 3 mm thickness which passes through the calvarial bone is dug at the parietal area by a diamond round disk for dental use.
2. A titanium rod equipped with titanium non-woven cloth (cut off to cylindrical shape of 3 mm diameter and 3 mm thickness) is inserted into the hole and perioste and dermis is closured.
3. The rabbit is killed after 4 weeks and the bone at the parietal area is removed and embeded by resin, then a ground specimen of 20 μm thickness is prepared. The specimen is dyed by hematoxylin-eosin dying method.
[0076] II. Experimental Results:
[0077] A tissue section specimen for microscope observation obtained in above item 3 is inspected by an optical microscope. Accordingly, following facts became clear as shown in FIG. 5 (A) and (B) and in FIG. 6 (A) and (B).
(i) In the case of a specimen which is prepared by equipping titanium non-woven cloth by 1 mm thickness around a titanium rod of 1.5 mm diameter and by carrying out hydroxyapatite coating with a liquid method and implanted in rabbit for 4 weeks, it is clearly observed that bone reaches to the deep part of titanium non-woven cloth layer and cover the surface of a titanium rod FIG. 5 (A) . (ii) In the composite prepared by equipping titanium non-woven cloth by 1 mm thickness around a titanium rod of 1.5 mm diameter and sintering in vacuum, and implanted without carrying out hydroxyapatite coating, it is clearly observed that bone formation does not grow sufficiently in titanium non-woven cloth part and is stopping at halfway FIG. 5 (B) . (iii) For the comparison, the experiment by a beads method, which is conventionally used, is carried out. That is, in the experiment implanting a titanium implant to which titanium beads are put on to a titanium rod (4 weeks passed), bone can not grow into the inside of titanium beads and remains at the outside FIG. 6 (A) . According to this result, the growth of bone into the inter bead spaces can not be expected at least in 4 weeks. (iv) Further, for the comparison, a self-healing experiment is carried out. That is, a hole of 3 mm diameter and 2.5 mm depth is dug in a calvarial bone of a rabbit and left for natural healing FIG. 6 (B) . According to this drawing, it is obvious that the missing part of 3 mm diameter and 2.5 mm depth, which is indicated in majority part of upper right part of the drawing, is already filled by spongy bone and regenerated naturally after four weeks. Bone grows from the inner periphery to the center part of the circle. From experimental results, it is confirmed that in the case of an apatite coated titanium rod equipped with titanium non-woven cloth, bone migrates into whole layer of non-woven cloth and reaches to the surface of the rod, while, in the cases of other materials or treating methods, it is difficult to reach to the deep part.
Example 4
[0000] Example for Apatite Coating Treatment
[0082] Apatite treating liquid and a method for apatite coating: Referring to the concentration of mineral in blood plasma of human, the treating liquid is prepared. Salts are added into distilled water so as the concentration of the treating liquid to become 5 times to blood plasma of human, then carbon dioxide gas is blown in through a ceramic filter, the salts are dissolved and pH of the liquid is adjusted to 6.01. The process is stopped at the point where all salts are dissolved and preserved in the atmosphere of carbon dioxide gas. This liquid is stable at the temperature of 37° C. for 1-2 weeks and does not generate precipitation. A titanium product to be coated is dipped in this liquid for 1 week, then observed by SEM.
[0083] The composition of the prepared liquid is shown below.
Sodium ion: 710 mM (millimoles per liter) Potassium ion: 25 mM Magnesium ion: 7.5 mM Calcium ion: 12.5 mM Chlorine ion: 720 mM Bicarbonate ion: 21 mM Phosphate ion: 5 mM Sulfate ion: 2.5 mM
Carbonate ion is the saturated concentration at weak acidity (pH 6.01) at 37° C. by blowing in carbonate dioxide.
[0084] The above mentioned liquid composition is one example and not intending to be limited to this example. Various liquids which generate apatite are reported in many documents, and anyone of these liquids can be used in the present invention.
[0085] As a specimen of the titanium metal fibers layer which is dipped, (a) sintered in vacuum type and (b) not sintered in vacuum type are used and compared. Results are shown in FIG. 7 (SEM pictures) (A) and (B). Deposition of fine crystal of apatite can be observed on the surface of both specimens, and there is no difference between two types, namely, sintered in vacuum and not sintered in vacuum. For the reference of this apatite coated titanium metal fiber non-woven cloth, the picture showing the state before coating is shown in FIG. 8 . FIG. 8 (A) shows the titanium non-woven cloth before heat treatment and FIG. 8 (B) shows the titanium non-woven cloth after heat treatment.
Example 5
[0086] Comparison experiments for cell cultivation comparing a conventional cell cultivation substrate with a bioreactor using fiber layer consisting of non-woven cloth made of titanium fibers whose average diameter is smaller than 100 μm or less and aspect ratio is 20 or more regulated in the present invention;
[0087] Experimental method: Necessary numbers of cultivation wells of 16 mm diameter are prepared, (1) titanium non-woven cloth or (2) porous apatite block is laid at the bottom of wells and (3) for blank test, a well with plastic board to which no sheet is laid. Same numbers of osteoblast MC3T3EI, which is established in worldwide, are sown in each well. The numbers of proliferated cells after 1 week and 3 weeks are measured by DNA measurement and compared.
[0088] Experimental results: Results are summarized in FIG. 9 . After 1 week the cells number increased to 1.4 times to that of plastic board and after 3 weeks increase to 1.3 times. On the contrary, a porous apatite block which is used as the conventional cell cultivation substrate has inferior cell cultivation ability than the plastic board. From said results, it can be said that the titanium non-woven cloth of the present invention is a very suitable substrate material for the mass cultivation of osteoblasts.
[0089] In above mentioned Examples, a scaffold material which indicates high affinity to osteoblasts is mainly disclosed, however, the present invention is also disclosing and providing a scaffold material which can be applied to cells besides bone cells and to living tissues, further a reactor material for cell cultivation and proliferation concerning all cells in regenerative medical engineering. This is clearly understood from these experiments and community of cells, and aforementioned 10 th to 12 th subjects, namely from item (10) to item (12) are carried out concerning those points.
[0090] A bioreactor has a very important position as a basic reaction device in life science in the circumstances where the development of artificial tissues and various organs are becoming to be realized and utilized. Considering these circumstances, the significance of the present invention is very big. The development of various regenerative medical engineering utilizing proliferation technique for stem cell, which is a current topic, and accompanying development of various tissues and organs which do not have after-effect contributes to the growth of medical science and welfare of human beings, and the present invention is taking part in said development and is greatly expected. That is, the object of the present invention is not limited to a biological hard tissue inductive or replacing scaffold material.
[0091] While, besides the aforementioned prior arts, techniques to fabricate a fiber layer using fibers or to form non-woven cloth of fibers and to induce living tissues into fiber gaps are proposed as an artificial blood vessel made from cloth and are presented in various papers, further published in many patent documents.
[0092] However, contents disclosed in these documents is not aiming at affinity of cells such as osteoblasts to materials, but aiming to reinforce the strength of blood vessel using fiber material and aiming natural filling of bonding tissue not to cause the leak of liquid from the inside of blood vessel. On the contrary, the present invention is requiring positive affinity with cells such as osteoblasts, therefore, titanium metal material is selected, especially, the specific fiber having very fine diameter of 100 μm or less is selected.
[0093] Regarding the trial to induce osteoblasts using metal fiber including titanium fiber, only there is a disclosure in Japanese Application Publication 8-140996 introduced in DESCRIPTION OF THE PRIOR ART. However, fine fiber disclosed in the document is a single filament whose diameter is from 0.1 mm to 0.7 mm diameter and is winded around a core. While, actually in the present invention, the titanium fiber is restricted to have 100 μm or less average diameter and to have lower limit of aspect ratio to 20 or more, and said fiber is used by entangling at random, therefore, space formed among these fibers is quite different from that of simple two dimensional space formed by conventional implanting method. That is, in the present invention, since cells are induced into the space formed by fibers and indicates high affinity, accordingly, proliferation speed is higher than that of the conventional method (3 to 6 months), and the formation of one body tissue can be observed after 4 weeks. Regarding this remarkably excellent action and effect of the present invention, however, in the said patent document, the reason why to provide metal filament is to expect buffering effect. There is no description teaching of various actions and effects such as generation of high affinity which is the unexpected effect of the present invention.
[0094] The technique to implant an artificial material into bone tissue and to fix it stable is very important to maintain mechanical function to the artificial organs, and without this technique, an artificial bone head (joint) or an artificial root of the tooth is unstable and releases soon. For the purpose to fix it stable, it is necessary that the interface between an implanted artificial material and bone is adhered without leaving gap and without interposing a tissue except bone or other subject, and required that the implanted subject and the bone to be chemically bonded strongly and not to be removed easily. Said connecting status between an implanted artificial material and bone is conventionally called as “osteoconduction” or “osteointegration”, and the technique to obtain this status as soon as possible after implanting artificial subject in bone is strongly required by many clinicians, researchers and patients. However, as recited in clause of DESCRIPTION OF THE PRIOR ART of the present invention, from 3 months in earlier case and 6 months in later case are needed to accomplish stable osteointegration, and it is necessary to keep rest during this period, further during this period it is difficult to recover the function and is impossible to progress to the next medical treatment.
[0095] Scaffold, namely an implant of the present invention is to increase surface area and is to attempt to make bone and an artificial subject one body by prompting the migration of bone into inside and the formation of a hybrid layer consisting of bone and the implant as shown in FIG. 1 ( b ). That is, as shown and illustrated in FIG. 1 ( a ), the present invention is quite different from the conventional two dimensional concept which adhere the surface of bone and the surface of an artificial implant. Three dimensional complicated space is formed by three dimensionally random entangled fibers and very rigid hybrid layer is formed in very short term of one month or less. Further, in said hybrid layer, since bone carries out metabolism in living state, it is stable from physiological view point, is durable to the outer force and combining natural reparation ability and can maintain the function of artificial viscera stable and semi-permanentally.
[0096] Specifically, although the essential point of the present invention is already mentioned in SUMMARY OF THE INVENTION and in Examples, the essential point of the present invention will be summarized and illustrated again. Said titanium layer is prepared by winding titanium whose average diameter is 100 μm or less around a bar or a rod (as the typical cross sectional view of the bar or the rod, circular or oval shape can be mentioned, however, any shape including square or rectangular shape is possible and can be selected properly according to a diseased part and is not restricted) made of the same kind of titanium metal or titanium group alloy to said titanium fibers by proper thickness and sintered in vacuum so as the contacting points of fibers each other and contacting points of the fiber with the implant to be fused and to be fixed without the fibers to be moved. By said process, the bar or the rod becomes one body with the fiber layer and a rigid product is formed. As mentioned in Examples, said rigid product provides a scaffold material or a bio reactor which is effective not only to an osteoblast but also to other cells. That is, by the present invention, besides the growth of osteoblast to have complex three-dimensional structure, the proliferation of cells themselves is accelerated and the excellent action and effect that the osteointegration tissue can be accomplished in short term.
[0097] In the present invention, since a medical material made of metal which needs affinity with bone, especially, fusing by sintering in vacuum is recited as one of main embodiment, the present invention is disclosed as a medical material composed of the same kind of titanium metal, however, the present invention can be used as the other medical materials and not intending to eliminate them.
[0098] For example, when the medical material of the present invention is used with a hydrophilic material having biodegradable property, it is expected to form a host tissue by replacing a host tissue with said medical material after implanted in an organism, and is suited to form a hybrid type tissue composed of hydrophilic resin and cells.
[0099] Since the present invention is possible to involve various cell growing factors to a hydrophobic material, it is possible to display its virtue for the induction of cells, which is impossible for a normal hydrophilic resin. Therefore, it is possible to form a specific functional tissue in an organism by collecting many artificially intended cells.
[0100] Since the present invention is possible to involve various cell growth preventing factors to a hydrophilic material, it is possible to form an environment where cells can not stuck in an organism. By applying this specific property, the tissue which can not be covered by cells for a long time can be formed in an organism, and can provide a space to carry out the sensing of various sensors in an organism. That is, quite different embodiments of use can be provided.
INDUSTRIAL APPLICABILITY
[0101] 1. The present invention is selecting very fine titanium fiber having a specific aspect ratio as a biological hard tissue inductive scaffold material used with various implants, forming random entangled fibers layer and inducing bone tissue into the inside of said titanium fibers layer, consequently makes it possible to form hybrid state possessing remarkably higher affinity of titanium with bone tissue compared with the conventional method applying a beads method or others. Namely, the present invention is to provide a medical material possessing very high affinity with bone tissue and the significance of the present invention is very large.
[0102] 2. Further, by carrying out subsidiary means such as sintering treatment in vacuum for shape maintenance, conducting the apatite coating treatment to accelerate the induction of osteoblasts or loading various bioactive substance, the remarkable action and effect that the induction of bone tissue characterized that bone tissue and implant are becoming one body and not leave imcompatibility can be provided with good reappearance. Thus, the present invention is expected to effect broadly to the field of orthopaedic surgery or to the field of odontology, and the significance of it is very large.
[0103] 3. The scaffold material of the present invention is not only superior to the conventional implanting method which is only a simple two dimensional growth and combination from the view point that the scaffold material of the present invention can progress the growth and development of cells three dimensionally, but also is proved that the growing and proliferating speed is superior to the conventional implanting method, therefore, can be evaluated greatly from this point. As repeatedly recited above, from the view point that the formation of osteointegration tissue is accomplished within one month, which is an unexpectedly short term from the conventional technique, by the present invention, that is, the present invention brings excellent effect and gospel both to a medical doctor and a patient at the actual medical spot and the significance of the present invention is very large.
[0104] 4. Further, since the present invention provides a material having high affinity not only to an osteoblast but also to various cells in an organism, the present invention can be said to provide not only a medical material but also a subject which acts as a reactor for cultivation and proliferation of cells in regenerative medical engineering, and the present invention is expected to contribute to the development of new medical industry. | It is intended to provide a scaffold whereby a bone and a metallic material can three dimensionally form together a stereoscopic binding layer. Thus, a geometric space sufficient for cell actions is provided. As a result, the time required for the formation of a stereoscopic bond can be shortened and, moreover, a bond can be self-repaired owning to cell actions even in the case where a pair of the bond is injured by a wound, etc. As a material for designing a scaffold, titanium fibers of less than 100 μm in size and having an aspect ratio of 20 or more are selected. Then these fibers are entangled together to form a layer which is integrally fixed by vacuum sintering to a periphery surface of the various implant bodies, and coated with apatite. The fact that the layer contains spaces of an excellent ability to induce a biological hard tissue and fix the same is proved by the material, in which the layer is fixed to the periphery of an implant. | 0 |
BACKGROUND OF THE INVENTION
This invention relates to a decorative paper which contains a pigment mixture of titanium dioxide and talc and the decorative coating materials obtained therefrom.
Decorative coating materials, so-called decorative sheets or decorative paper [paper impregnated with synthetic resin] is preferably used for surface coating in production of furniture and in completion of interiors. Decorative sheets are understood to be printed or unprinted sheets of paper impregnated with a synthetic resin and optionally treated at the surface. Decorative sheets are glued or bonded to a backing board.
Depending on the type of impregnation process, a distinction is made between decorative sheets with a thoroughly impregnated paper core and decorative sheets based on a preimpregnate, in which the paper is impregnated only partially online in the papermaking machine. Molded laminated materials (high-pressure laminates) are laminates produced by pressing several impregnated layered papers. The structure of these molded laminated materials consists in general of a transparent layer (overlay) which produces an extremely high surface stability, a decorative paper impregnated with a synthetic resin and one or more kraft papers impregnated with a phenolic resin. Molded fiber board and particle board as well as plywood can be used as the substrate for this.
In the laminates (low-pressure laminates) produced by the short-cycle method, the decorative paper impregnated with synthetic resin is pressed directly with a substrate, e.g., a particle board using a low pressure. The decorative paper used in the coating materials mentioned above is white or colored and may be with or without an additional imprint.
Special requirements are made of so-called decorative base paper such as high opacity for a better coverage of the substrate, uniform formation and grammage of the sheet for uniform resin uptake, high light stability, high purity and uniformity of the color for good reproducibility of the pattern to be printed, high wet strength for a smooth impregnation operation, suitable absorbency to achieve the required degree of resin saturation and dry strength which are important in re-rolling operations in the papermaking machine and in printing in the printing machine.
Decorative base paper is generally made of high-white sulfate pulp, mainly from hardwood pulp, up to 45% pigments and fillers and wet strength, retention agents and fixing agents. Decorative base paper differs from the usual paper in that it has a much higher filler content and there is none of the internal sizing or surface sizing which is usual in paper with the known sizing agents such as alkyl ketene dimers.
Opacity is one of the most important properties of decorative base paper. This characterizes the coverage with respect to the substrate.
A high opacity of the decorative base paper is also achieved by adding white pigments. Titanium dioxide is usually used as the white pigment. This pigment guarantees a high opacity and a good brightness and whiteness of the decorative base paper. However, the high price of titanium dioxide is a disadvantage.
Replacing some or all of the titanium dioxide with other white pigments has a negative effect on these properties. Matching of opacity can be achieved only by increasing the pigment content. However, the pigment content cannot be increased to an unlimited extent, because in this case, negative effects on the physical properties such as retention of the pulp suspension, strength, light-fastness and resin uptake can be expected.
SUMMARY OF THE INVENTION
The object of this invention is to make available an inexpensive decorative paper with a high opacity while at the same time having a reduced titanium dioxide content.
This object is achieved by a decorative base paper for decorative coating materials, wherein said decorative base paper contains a pigment mixture of a titanium dioxide and talc. The talc used according to this invention has a very narrow particle size distribution with a D50 of less than about 3 μm. This means that 50 wt % of the talc particles have a diameter of less than about 3 μm. Talc with a particle size distribution D50 of less than about 2 μm is especially preferred.
According to a further embodiment a decorative paper or decorative sheet is provided that includes the aforementioned decorative base paper.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The specific surface area of the talc used according to this invention is greater than about 30,000 m 2 /kg, or according to an especially preferred embodiment it is greater than about 40,000 m 2 /kg. On the other hand, the specific surface area of traditional types of talc is in the range of 8,000 to 16,000 m 2 /kg. The specific surface area was determined according to DIN 66,126.
The amount of talc in the pigment mixture is preferably 0.1 to 25 wt %, based on the total pigment content.
The titanium dioxide preset in the pigment mixture used in the decorative base paper according to this invention may be a titanium dioxide conventionally used in decorative paper. Such titanium dioxides are available commercially and may be used in the rutile or anatase modification. Such titanium dioxides of the rutile type are especially preferred.
Other fillers such as zinc sulfide, calcium carbonate, kaolin or mixtures thereof may be used.
The amount of filler in the decorative base paper may be up to 55 wt %, in particular 11 to 50 wt % or 20 to 45 wt %, based on the weight of the paper. The weight of the decorative base paper according to this invention may be in the range of 30 to 300 g/m 2 and is usually 40 to 200 g/m 2 . The weight is selected as a function of the specific application.
Softwood pulp (long-fiber pulp) or hardwood pulp (short-fiber pulp) may be used as the cellulose pulp for producing the decorative bulk paper according to this invention. It is also possible to use cotton fibers or mixtures of the types of cellulose mentioned above. For example, a mixture of softwood pulp and hardwood pulp in a ratio of 10:90 to 90:10 or mixtures of softwood pulp and hardwood pulp in a ratio of 30:70 to 70:30 are especially preferred. The pulp may have a degree of beating of 20 to 60 SR according to Schopper-Riegler.
The cellulose pulp mixture preferably has a cationically modified cellulose fiber content of at least 5 wt %, based on the weight of the cellulose mixture. A content of 10 to 50 wt %, in particular 10 to 20 wt % of the cationically modified cellulose in the cellulose pulp mixture has proven to be especially advantageous.
Cationically modified cellulose pulps are known from the journal Das Papier , volume 12 (1980), pp. 575-579, for example.
In a special embodiment of this invention, the cationically modified cellulose contained in the paper pulp has an effective cationic charge of 20 to 300 mmol/kg pulp, determined according to the internal method no. 4 of the Technical University of Darmstadt. Cellulose pulp fibers with a charge density of 30 to 100 mmol/kg are preferred. The term “effective cationic charge” is understood to refer to a charge density which has been balanced with the charge density of the non-cationized cellulose pulp. The charge density of the cellulose pulp depends on the amount of cationic agent to be used. The amount of cationizing agent may be 0.005 to 200 g/kg cellulose pulp.
The cationic modification of the cellulose pulp fibers may be accomplished through reaction of the fibers with epichlorohydrin resin and a tertiary amine or by reaction with quaternary ammonium chlorides such as chlorohydroxypropyl-trimethyl-ammonium chloride or glycidyltrimethyl-ammonium chloride.
In a preferred embodiment of this invention, cellulose pulp fibers that have been cationically modified by an addition reaction of quaternary ammonium compounds having glycidyl functional groups with hydroxyl groups of cellulose are used.
The decorative bulk paper according to this invention may contain wet strength agents such as polyamide/polyamine-epichlorohydrin resin, other polyamine derivatives or polyamide derivatives, cationic polyacrylates, modified melamine-formaldehyde resin or cationized starches. These are added to the pulp suspension. Likewise, it is also possible to add retention aids and other substances such as organic and inorganic colored pigments, dyes, optical brighteners and dispersants.
The decorative bulk paper according to this invention can be produced on a Fourdrinier papermaking machine or a Yankee papermaking machine. To do so, the cellulose pulp mixture may be pulped to a degree of beating of 30 to 45 SR at a pulp density of 2 to 4 wt %. In a mixing vat, fillers such as titanium dioxide and talc, and wet strength agents are added and mixed well with the cellulose pulp mixture. The resulting thick pulp is diluted to a pulp density of approximately 1 wt %, and other additives such as retention aids, foam suppressant, aluminum sulfate and other additives as listed above are added as needed. This thin pulp is passed through the headbox of the papermaking machine and sent to the wire section. A fiber nonwoven is formed, yielding after drainage the decorative base paper which is then dried.
To produce decorative paper, the decorative base paper is impregnated with the conventional synthetic resin dispersions for this purpose. The conventional synthetic resin dispersions for this purpose include, for example, those based on polyacryl or polyacrylmethyl esters polyvinyl acetate, polyvinyl chloride or synthetic resin solutions based on phenol-formaldehyde precondensates, urea-formaldehyde precondensates or melamine-formaldehyde precondensates or their compatible mixtures.
The impregnation may also be accomplished in the size press of the papermaking machine. The decorative base paper can be impregnated in such a way that the paper is not completely impregnated. Such decorative paper is also known as a preimpregnate. The amount of resin introduced into the decorative base paper by impregnation in this case amounts to 25 to 30 wt %, based on the weight of the paper.
After drying, the impregnated paper can also be coated and printed and then applied to a substrate such as a wooden board. The coated and optionally printed products are generally known as decorative sheets.
The following examples are presented to further illustrate this invention. Amounts given in percent by weight are based on the weight of the cellulose pulp, unless otherwise indicated.
EXAMPLE 1
A cellulose pulp mixture consisting of 70 wt % eucalyptus pulp and 30 wt % softwood sulfate pulp was mixed with 0.6 wt % epichlorohydrin resin as the wet strength agent, 0.11 wt % of a retention aid and 0.03 wt % of a foam suppressant as the basic mixture. The latter three percentages are based on the weight of the pulp. The pH of this mixture was adjusted to 6.5 with aluminum sulfate. This mixture was then mixed with a pigment mixture of 55.8 wt % titanium dioxide and 5.2 wt % talc. Using a Fourdrinier papermaking machine, a decorative paper with a grammage of 105 g/m 2 was produced. The titanium dioxide content was 33.5 g/m 2 (31.9 wt %) and the talc content was 3.1 g/m 2 (2.95 wt %). The talc had a particle size distribution D50 of 1.9 μm and a specific surface area of 44,300 m 2 /kg.
EXAMPLE 2
A pigment mixture of 50.3 wt % titanium dioxide and 14.7 wt % talc was added to the basic mixture from Example 1. A decorative paper with a grammage of 105 g/m 2 was produced with a Fourdrinier papermaking machine. The titanium dioxide content was 30.2 g/m 2 (28.8 wt %) and the talc content was 8.8 g/m 2 (8.4 wt %). The talc had a particle size distribution D50 of 1.9 μm and a specific surface area of 44,300 m 2 /kg.
EXAMPLE 3
A pigment mixture of 64.5 wt % titanium dioxide and 3.3 wt % talc was added to the basic mixture from Example 1. A decorative paper with a weight of 105 g/m 2 was produced on a Fourdrinier papermaking machine. The titanium dioxide content was 38.7 g/m 2 (36.5 wt %) and the talc content was 2.0 g/m 2 (1.9 wt %). The talc had a particle size distribution D50 of 1.9 μm and a specific surface area of 44,300 m 2 /kg.
EXAMPLE 4
A pigment mixture of 53.9 wt % titanium dioxide and 11.3 wt % talc was added to the basic mixture from Example 1. A decorative paper with a weight of 105 g/m 2 was produced on a Fourdrinier papermaking machine. The titanium dioxide content was 32.3 g/m 2 (30.8 wt %) and the talc content was 6.8 g/m 2 (6.5 wt %). The talc had a particle size distribution D50 of 1.5 μm and a specific surface area of 47,100 m 2 /kg.
Comparative Example 1
As Comparative Example 1, only a 62 wt % titanium dioxide dispersion was added to the basic mixture from Example 1. A decorative paper with a weight of 120 g/m 2 and a titanium dioxide content of 37.2 g/m 2 (31 wt %) was produced using a Fourdrinier papermaking machine.
Comparative Example 2
A pigment mixture of 50.8 wt % titanium dioxide and 14.4 wt % talc was added to the basic mixture from Example 1. A decorative paper with a weight of 105 g/m 2 was produced on a Fourdrinier papermaking machine. The titanium dioxide content was 30.5 g/m 2 (29 wt %) and the talc content was 8.7 g/m 2 (8.3 wt %). The talc had a particle size distribution D50 of 3.7 μm and a specific surface area of 8,600 m 2 /kg.
The opacity of paper samples from Examples B1 through B4 and Comparative Examples V1 and V2 was determined according to DIN 53,146 by using an ACE color measuring instrument from Data Color. The titanium dioxide content of the decorative base paper was determined according to DIN 54,370. The results are summarized in the following table.
Talc content, based on
Opacity
total pigment
Talc content
Sample
(%)
(%)
(g/m 2 )
B1
92.68
8.5
3.1
B2
92.55
22.6
8.8
B3
92.61
4.9
2.0
B4
92.62
17.3
6.8
V1
92.71
0.0
0.0
V2
90.28
22.2
8.7
The results of the opacity measurements show that a high opacity can be achieved with the talc used according to this invention even with a greatly reduced titanium dioxide content. | A decorative base paper for decorative coating materials contains a pigment mixture of titanium dioxide and talc, wherein the talc has a particle size distribution D50 of less than approximately 3.0 μm, and both the decorative base paper and the decorative paper have a high capacity. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No. 11/291,134 filed on Nov. 30, 2005, which claims the benefit of U.S. Provisional Patent Application No. 60/676,238, filed on Apr. 29, 2005.
TECHNICAL FIELD
[0002] The embodiments relate generally to computer software. More specifically, the embodiments relate to a computer software program for ensuring the accuracy of healthcare patient data entered into a computer system during patient registration.
BACKGROUND
[0003] For hospitals, doctor's offices, and other similar medical facilities, patient intake is a critical step in their operations. Not only is patient data necessary for proper treatment, but also correct patient data can have a significant impact on the financial operation of the facility. If a patient's intake data is incorrect, financial payment through billing, insurance claims, etc. may be delayed.
[0004] Typically, data entry clerks called “registrars” or “patient access representatives” conduct patient intake. The registrars are typically low paid employees that perform a difficult, repetitive and thankless job. Often the employee has inadequate time and resources available for proper training. Additionally, registrars are under pressure to provide speedy and friendly service to all patients. In summary, registrars are tasked with collecting complex and vital information from sick patients as quickly as possible.
[0005] Studies have shown that error rates for a typical hospital registration average 30%. These errors generally fall into three categories. The first type is “compliance” errors that deal with legal requirements such as guardianship of a minor seeking admission to the hospital and patient safety issues such as duplicate medical record numbers. The second type is “financial” errors that are necessary to receive payment such as an insurance policy number. Finally, the third type of errors is “operational” errors that will delay payment if incorrect such as an incorrect billing address. The cause of any of these errors may be the result of human error of the registrar, incorrect information provided by the patient, or a change in the patient's information. Even small error rates result in patient safety risk, costly revenue delays and possibly billing write offs due to insurance rejections.
[0006] In common insurance industry forms, such as a “UB-92,” eighty six separate data fields are required. Typically, 70% of these fields are entered by registrars rather than billing or clinical staff. Surveys have shown that up to 75% of billing office staff are dedicated to rework or correction of patient data before billing. One prior art solution is manual review of patient data prior to billing. However, this method is limited to random samples of registrations due to high volumes, and is without feedback or accountability to the error makers, so it is ineffective at reducing error rates. Manual review is also burdensome, costly, subjective, inconsistent, and highly dependent upon the skill and ability of the reviewer. Another prior art solution involves the use of “electronic claim validation systems” or “bill scrubbers” which are computer software programs that check the patient data immediately prior to billing. However, this method provides no accountability or statistical analysis of the registrars since billing office staff makes any corrections. Another prior art method involves the use of “pop ups” to prompt the registrar of an error immediately upon entry or directly after each registration is completed. However, this method slows the registration and admissions process for the patient and consequently is not customer friendly.
SUMMARY
[0007] In some aspects, the invention relates to a method for ensuring accuracy of electronic medical patient intake data, comprising: entering medical intake data for a plurality of patients into a computer system; arranging the intake data for the plurality of patients into a batch; analyzing the batch of intake data at a predetermined interval for errors; and generating an alert for errors in the batch of intake data.
[0008] In other aspects, the invention relates to a method for ensuring accuracy of electronic medical patient intake data, comprising: step for entering a batch medical intake data for a plurality of patients into a computer system; step for analyzing the batch of intake data at a predetermined interval for errors; and step for generating a report for any errors found in the batch of intake data.
[0009] In one embodiment, a method of ensuring accuracy of healthcare patient data entered into a primary computer system by a user during patient registration is provided. Healthcare patient data for a patient entered into the primary computer system is electronically received. The received healthcare patient data is analyzed using a secondary computer processor programmed to identify data entry errors including discrepancies and omissions. The identified errors are automatically presented to the user by the programmed secondary computer processor following analysis of the healthcare patient data. The identified errors are placed into a work list by the programmed secondary computer processor to enable the user to enter corrections for the identified errors into the primary computer system within a designated time-frame.
BRIEF DESCRIPTION OF DRAWINGS
[0010] It should be noted that identical features in different drawings are shown with the same reference numeral.
[0011] FIG. 1 shows a display of a main menu in accordance with one embodiment of the present invention.
[0012] FIG. 2 shows a display of a maintenance menu in accordance with one embodiment of the present invention.
[0013] FIG. 3 shows a display of a report menu in accordance with one embodiment of the present invention.
[0014] FIGS. 4A and 4B show displays of a manager report by error type in accordance with one embodiment of the present invention.
[0015] FIG. 5A shows a display of a menu used to specify the parameters for an error report in accordance with one embodiment of the present invention.
[0016] FIG. 5B shows a display of an error report sent to a registrar to correct errors in accordance with one embodiment of the present invention.
[0017] FIG. 6 shows a display of a detailed error report in accordance with one embodiment of the present invention.
[0018] FIG. 7 shows a display of a manager report by location and employee in accordance with one embodiment of the present invention.
[0019] FIG. 8 shows a display of a manager report by error type in accordance with one embodiment of the present invention.
[0020] FIG. 9 shows displays of a manager report for an employee's productivity and error rate in accordance with one embodiment of the present invention.
[0021] FIG. 10 shows a display of an error trend report by employee in accordance with one embodiment of the present invention.
[0022] FIG. 11 shows a display of insurance eligibility edits in accordance with one embodiment of the present invention.
[0023] FIG. 12 shows a display of a selective employee error setup form in accordance with one embodiment of the present invention.
[0024] FIG. 13 shows a display of a selective employee error report in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0025] A method for ensuring the accuracy of medical patient intake data has been developed. The present invention involves using a computer software program to “audit” or check the accuracy of patient data entries and identify errors. It can be deployed on a single user computer or on a shared network for simultaneous multi-user access. The checking for errors or “edits” is done periodically by a “batch” of patient entries. A batch is defined as a group of more than one patient. For example, the present invention could audit all of the entries for each patient processed by a registrar once a day. Other embodiments of the invention may audit at different intervals as dictated by the needs of the user. However, audits should take place on the “front end” or before the bills are produced to be sent out for payment. By conducting periodic audits of 100% of all registrations, registrars are allowed to self-correct their errors prior to billing.
[0026] Additionally, the present invention can provide managers with statistical data regarding the error rate of patient data entries. Such error rates may be monitored according to employee, error type, or location, etc. This provides management with an objective basis for effective identification of problem areas and subsequent training for employees. Additionally, the registrars may be provided with ongoing feedback of their performance.
[0027] The figures show examples of displays used by one version of the present invention called “AccuReg.” FIGS. 1-3 each show display menus in accordance with one embodiment of the present invention. These menus are used to access and utilize the various features of the invention. FIGS. 4A and 4B show displays of a manager report by error type in accordance with one embodiment of the present invention. The report categorizes the errors by description, type (e.g., compliance, operational, or financial), raw number of a particular error, error rate of a particular error, and cost to correct all errors of a particular type. FIG. 5A shows a screen for specifying the parameters of an error report.
[0028] Also shown in FIG. 5B is an example of an error report generated by a periodic audit for a registrar. This is used to correct errors. FIG. 6 shows displays of additional detailed error reports provided to the registrars. FIGS. 7-13 show displays of reports for managers that detail number of errors by individual employees along with their error rate. Also shown are reports that break down error trends and productivity by individual employee, employee group, and overall performance. As clearly shown, the present invention provides a great deal of flexibility to managers in the way information regarding error rates is collected. It should be understood that alternative embodiments of the present invention may utilize the reporting capability in a variety of ways according to the needs of the user.
[0029] Some additional features of the invention may include the use of “eligibility edits.” This is a particular type of edit that uses data from a hospital's electronic eligibility system to identify registration errors. An electronic eligibility system returns demographic and insurance information to the registrar for the purpose of verifying coverage, benefits and co-pay information. Since the source of this eligibility information is insurance company or other payer databases, it is arguably the most accurate storehouse of information regarding the patient and subscriber. It is also the information that insurance companies require on the claim forms in order for them to reimburse the providers without delay or denial. FIG. 11 shows examples of these edits. However, due to the time constraint during registration and the complexity of the information, many hospitals do not take full advantage of this information.
[0030] The use of eligibility edits allow the hospital to identify errors by comparing specific data elements keyed by the registrar to the same data elements according to the payer's database. For example, the social security number keyed by the registrar is compared to the social security number according to the insurance eligibility transaction file for that patient. If the registrar mis-keyed even one out of the expected nine digits, the invention will identify the error and report it to the clerk in the registrar's daily error report along with other errors. The report will show registrars what was keyed incorrectly as well as what should have been keyed according to the payer, allowing them to efficiently make corrections so that the billing cycle is not impacted. This new capability significantly improves the invention's ability to positively impact the revenue cycle of a hospital by enforcing the use of eligibility data that the hospital is already paying for but not using.
[0031] Another feature of the invention may include the use of “second pass reporting.” This feature is a double check that insures errors reported will be corrected. The present invention will re-audit accounts that were audited 2 to 3 days before to make sure the errors were corrected during that period of time. If the same error appears at a specified interval (e.g., 3 days) after it was first reported to the employee, the supervisor and employee are made aware of it with “second pass reports.” It is a second pass or second opportunity to identify and correct errors. Supervisors will be able to view summary statistics to identify employees who routinely fail to correct errors on the first pass. Furthermore, accounts that were improperly corrected are identified; insuring even greater accuracy and employee accountability. This reporting capability is unique and adds an enforcement aspect to insure hospital managers that errors will be corrected. It also insures that the invention will produce results for the hospital in terms of prevention of denials and reduction of rework.
[0032] Some embodiments of the invention allow a supervisor to select an employee, to choose a time frame, to select one or more of that employee's top errors for that period, and then choose to print or email a detailed retrospective list of those errors. This provides the supervisor with the ability to quickly produce select detailed error information for any employee for management or retraining purposes. A screenshot of the setup form is shown in FIG. 12 , followed by a sample report shown in FIG. 13 .
[0033] Other embodiments of the invention utilize “double-check” edits. These edits involve particular situations where an error type is difficult to consistently and accurately identify (e.g., a misspelled name, incorrect zip code, incorrect area code). In this embodiment, the invention can set any edit to “double-check” status, meaning that the edit will report the possible error to the employee on their error report with instructions to double check the entry. This indicates to the employee that they should conduct a second review of the data and correct it if necessary. Additionally, the invention allows managers to set any edit to be reported but not counted against the employee's statistics or affect their accuracy rates. This is useful to managers in cases such as “double-check” edits, where the managers can enforce errors to be reported and reviewed but not necessarily counted.
[0034] Embodiments of the present invention include a wide variety of formats for the presentation of data. For example, the reports generated by the invention may be accessed only by managers in some configurations. Because the registration employees do not need access to the software to obtain reports and demonstrate accountability, there is no need to train and re-train dozens or hundreds of registrars to use it. This adds an important accountability step to the process where the employee receives their daily error report from their supervisor.
[0035] In certain embodiments, a manager would prefer to get a particular edit or error type reported to them as a “worklist” rather than to the employee for correction. For example, duplicate medical record numbers can be a patient safety risk so a manager may choose to report that particular error separately for only the manager to correct. A “worklist edit” allows a manager to keep such errors from reporting to the employees for correction, and allows the manager a way to find and fix the error with full knowledge of which employee made the error, but report and correct it in a different way than normal edits.
[0036] Other embodiments of the invention will contain full color bar and line charts within the generated reports. This significantly improves the readability of the reports and makes interpretation and decision making more efficient for managers. The invention may also produce a report to demonstrate to hospital managers the financial return on their investment (ROI). For example, the ROI may be calculated by determining the labor expense saved due to reduction of rework or the denials prevented due to early detection and correction.
[0037] The present invention results in a significant reduction in the error rate of patient admissions. Additionally, management is provided with statistical tools to identify and correct problem areas as they occur. While the embodiments of the present invention have been described with respect to admission of patients to a hospital, the invention could apply to admission to other medical facilities such as a doctor or dentist office. Further, the invention could also be applied to any non-medical organizations where the intake of customer data is critical to administrative functions. In summary, the advantages of the present invention include: front-end auditing of patient intake data in periodic batches; allowing for employee accountability and improvement of employee competency; and reporting of errors to management in a format that allows for analysis of error statistics.
[0038] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the appended claims. | A method of ensuring accuracy of healthcare patient data entered into a primary computer system by a user during patient registration. Healthcare patient data for a patient entered into the primary computer system is electronically received. The received healthcare patient data is analyzed using a secondary computer processor programmed to identify data entry errors including discrepancies and omissions. The identified errors are automatically presented to the user by the programmed secondary computer processor following analysis of the healthcare patient data. The identified errors are placed into a work list by the programmed secondary computer processor to enable the user to enter corrections for the identified errors into the primary computer system within a designated time-frame. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention generally relates to a resistive device, and in particular to a resistive device with flexible substrate.
[0003] 2. Description of Prior Art
[0004] As technology of electric circuit has a continuous development, the requirement for stability of resistance of a resistive device is increased. Some features such as temperature coefficient of resistance (TCR) of traditional chip type resistive device have been not satisfied for the requirement of high stability so that the application is limited.
[0005] As shown in FIG. 1 , in order to enhance the heat stability of resistance of a resistive device, there has a conventional resistive device 10 provided. The resistive device 10 has a substrate 11 made of ceramic material, a resistive layer 12 located on a lower surface of the substrate 11 , a copper foil layer 13 located on an upper surface of the substrate 11 , side electrodes 14 respectively located at two sides of the substrate 11 and a protective layer 15 located on the copper foil layer 13 . The operative power of the resistive device 10 can be enhanced by the copper foil layer 13 which has excellent heat dissipation to dissipate the heat generated when the resistive device 10 is operated.
[0006] However, as the electric device pursues a trend of miniaturization, the resistive device should follow the trend of miniaturization. The substrate of the above resistive device is made of ceramic which is easy to crack during the manufacturing process due to hardness and brittleness. Therefore, there is a limitation for further miniaturizing the resistive device. Moreover, a conventional adhesive for adhering the substrate 11 and the resistive layer 12 or the copper foil layer 13 may contain glass fiber material to provide a preferable support after curing. However, the glass fiber material has poor flexibility after curing, so that there is another limitation for the application of the resistive device. Also, because glass fiber material has poor heat dissipation and may block the heat transfer from the substrate 11 toward the resistive layer 12 or the copper foil layer 13 , the operative power of the resistive device 10 cannot be enhanced.
SUMMARY OF THE INVENTION
[0007] It is one object of the present invention to provide a resistive device having a substrate made without using ceramic material in order to reduce the size.
[0008] To achieve the above object, the present invention provides the resistive device having flexible substrate. The resistive device comprises a flexible substrate, a resistive layer and an electrode layer. The flexible substrate may be located on the resistive layer. The electrode layer has a first electrode part and a second electrode part located on the resistive layer opposed to the flexible substrate and separated with each other.
[0009] The invention provides a method for manufacturing a resistive device having flexible substrate comprising steps of providing a flexible substrate; forming a resistive layer on the flexible substrate; and forming an electrode layer located on the resistive layer opposed to the flexible substrate. The electrode layer has a first electrode part and a second electrode part separated with each other.
[0010] In addition, the invention provides another method for manufacturing a resistive device having flexible substrate comprising steps of providing a flexible substrate and a resistive layer directly attached with each other; and forming an electrode layer located on the resistive layer opposed to the flexible substrate. The electrode layer has a first electrode part and a second electrode part separated with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a sectional view of a convention resistive device.
[0012] FIG. 2 shows a sectional view of a first embodiment of resistive device according to the invention.
[0013] FIG. 3 shows a sectional view of a second embodiment of resistive device according to the invention.
[0014] FIG. 4 shows a sectional view of a third embodiment of resistive device according to the invention.
[0015] FIG. 5 shows a sectional view of a fourth embodiment of resistive device according to the invention.
[0016] FIG. 6(A) to FIG. 6(G) show schematic view of steps of a method for manufacturing a resistive device of the invention.
[0017] FIG. 7(A) to FIG. 7(E) show schematic view of steps of another method for manufacturing a resistive device of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The detailed description and technical content of the present invention with reference to the drawings, which merely provides reference and illustration without having an intention to limit the present invention, illustrates as following.
[0019] Please refer to FIG. 2 . FIG. 2 shows a first embodiment of a resistive device according to the present invention. The resistive device 20 mainly includes a flexible substrate 100 , a resistive layer 110 located on the flexible substrate 100 , an electrode layer 120 located on the resistive layer 110 opposed to the flexible substrate 100 , and an adhesive layer 130 between the resistive layer 110 and the flexible substrate 100 .
[0020] The resistive layer 110 is made of Ni—Cu alloy, Ni—Cr alloy, F—Cr alloy, Cu—Mn alloy, Cu—Mn—Sn alloy, Ni—Cr—Al alloy, Ni—Cr—Fe alloy, and so on. In the embodiment, the resistive layer 110 is a sheet of Ni—Cu alloy with a thickness of 50˜300 μm. The resistive layer 110 is a whole rectangular sheet or may form special shape of opening or groove thereon to have a predetermined resistance value.
[0021] The flexible substrate 100 is plastic material, such as polyimide (PI), polyethylene terephthalate (PET), bismaleimide-triazine resin (BT resin), having preferable chemical stability with a thickness of 12˜45 μm.
[0022] The adhesive layer 130 may be material of epoxy and acrylic resin etc. with a thickness of 13˜102 μm. Also, the adhesive layer 130 may be a heat dissipation adhesive with a property of heat dissipation.
[0023] The electrode layer 120 includes a first electrode part 121 and a second electrode part 122 located at two opposite sides of a lower surface of the resistive layer 110 . The first electrode part 121 and a second electrode part 122 have material of copper or copper alloy. In addition, the resistive device 20 of the embodiment may further include a first outer welding layer 126 covering the first electrode part 121 and a second outer welding layer 127 covering the second electrode part 122 . The first outer welding layer 126 and the second outer welding layer 127 may be used to connect other external components. The first outer welding layer 126 and the second outer welding layer 127 may include a single welding layer or welding multi-layer such as Ni layer and Sn layer formed by electroplating or sputtering process.
[0024] In order to prevent the resistive layer 110 from contamination or oxidation, a first protective layer 140 may cover on the lower surface of the resistive layer 110 between the first electrode part 121 and the second electrode part 122 . Furthermore, the resistive device 20 of the embodiment may further cover a second protective layer 150 on an upper surface of the flexible substrate 100 . The first protective layer 140 and the second protective layer 150 may have material of epoxy and acrylic resin.
[0025] In the embodiment, there is not provided a ceramic substrate that is hard to work in the resistive deviceso that the resistive device can be easily further reduced the size. In addition, because both the flexible substrate 100 and the adhesive layer 130 are flexible, the resistive device 20 may have preferable flexibility, and thus the use of the resistive device is wide-spreading.
[0026] Also, the flexible substrate 100 may be easily made thinner because of good workability in such a manner that the resistive device 20 of the present invention has lower thermal impedance. The adhesive layer 130 of the present invention may have preferable heat conductivity due to without using glass fiber.
[0027] Please refer to FIG. 3 . FIG. 3 shows a second embodiment of a resistive device according to the present invention. The difference between the second embodiment and the first embodiment is that the resistive device 30 of the second embodiment may further include a metal layer 160 sandwiched between the flexible substrate 100 and the second protective layer 150 . The effect of heat dissipation of the resistive device 30 can be enhanced by preferable heat conductivity of the metal layer 160 . In this embodiment, the metal layer 160 may preferably have a thickness of 8˜105 μm, further preferably have a thickness of 8˜70 μm, and particularly preferably have a thickness of 8˜35 μm of copper, copper alloy or other metal material with preferable heat dissipation.
[0028] Please refer to FIG. 4 . FIG. 4 shows a third embodiment of a resistive device 40 according to the present invention. The difference between the third embodiment and the second embodiment is that the resistive device 40 of the third embodiment may further include a metal layer 160 having a first metal sheet 162 and a second metal sheet 164 separated with each other, and sandwiched between the flexible substrate 100 and the second protective layer 150 . There is no limitation for the shape of the first metal sheet 162 and the second metal sheet 164 , and the shape may be directed according to the required heat dissipation. In this embodiment, the second protective layer 150 covers the first metal sheet 162 and the second metal sheet 164 , and fills into an area between the first metal sheet 162 and the second metal sheet 164 . In another embodiment, the second protective layer 150 may only fill into the area between the first metal sheet 162 and the second metal sheet 164 without covering the first metal sheet 162 and the second metal sheet 164 . In the embodiment, the first metal sheet 162 and the second metal sheet 164 may have material of copper or copper alloy with a preferable thickness of 8˜105 μm, a further preferable thickness of 8˜70 μm and a particular preferable thickness of 8˜35 μm.
[0029] Please refer to FIG. 5 . FIG. 5 shows the fourth embodiment of a resistive device according to the present invention. The difference between the fourth embodiment and the first embodiment is that the resistive device 50 of the fourth embodiment has no adhesive layer for adhering the resistive layer 110 on the lower surface of the flexible substrate 100 . The resistive layer 110 is directly attached to the flexible substrate 100 .
[0030] A method for manufacturing a resistive device of the invention is described as following. Please refer to FIG. 6(A)˜FIG 6 (G). At first, as shown in FIG. 6(A) , a flexible substrate 100 and an adhesive layer 130 are provided, wherein the flexible substrate 100 has a metal layer 160 attached on an upper surface thereof, and the adhesive layer 130 may attach on a release film 170 ; the release film 170 can be removed after the adhesive layer 130 is attached on the flexible substrate 100 . Next, as shown in FIG. 6(B) , the flexible substrate 100 is attached on the resistive layer 110 with the adhesive layer 130 , and the flexible substrate 100 and the resistive layer 110 adhere close with the adhesive layer 130 by thermal press to form a plate assembly, as shown in FIG. 6(C) .
[0031] Next, as shown in FIG. 6(D) , the resistive layer 110 is etched to form a recess 111 for adjusting the resistance value of the resistive layer 110 . Also, the metal layer 160 is etched to form a groove 161 , and thus a first metal sheet 162 and a second metal sheet 164 separated with each other are formed.
[0032] Next, as shown in FIG. 6(E) , a first electrode part 121 and a second electrode part 122 having electrical conductive function located at two opposite sides of a lower surface of the resistive layer 110 are formed by electroplating, press fitting or welding process.
[0033] Next, as shown in FIG. 6(F) , a first protective layer 140 is formed on the lower surface of the resistive layer 110 between the first electrode part 121 and the second electrode part 122 to prevent the resistive layer 110 from contamination or oxidation. Also, a second protective layer 150 is formed on an upper surface of the flexible substrate 100 to provide enough strength for supporting the resistive device.
[0034] At last, as shown in FIG. 6(G) , a first outer welding layer 126 covering the first electrode part 121 and a second outer welding layer 127 covering the second electrode part 122 are formed to increase the adhesion of the first electrode part 121 and the second electrode part 122 , and to increase the bonding strength between the resistive device and PCB.
[0035] It should be noted, with the above manufacturing method, the flexible substrate 100 having a metal layer 160 on an upper surface thereof is provided in the beginning. In the another embodiment, the above manufacturing method may proceed by only the remaining flexible substrate 100 . For example, the embodiment of the method may manufacture the resistive device of FIG. 3 or FIG. 4 with the metal layer 160 . The embodiment of the method may manufacture the resistive device of FIG. 2 without the metal layer 160 .
[0036] As shown in FIG. 7(A)˜FIG . 7 (E), which illustrate another method for manufacturing a resistive device of the present invention. As shown in FIG. 7(A) , a flexible substrate 100 and a resistive layer 110 directly attached with each other are provided, wherein there is no adhesive layer between the flexible substrate 100 and a resistive layer 110 for adhering them. In one embodiment, the flexible substrate 100 is directly formed on the resistive layer 110 , for example, a liquid soft material is coated or printed on the resistive layer 110 , and then the flexible substrate 100 is formed and attached on the resistive layer 110 by curing the liquid soft material. In another embodiment, the resistive layer 110 may be formed on the flexible substrate 100 by film-forming method, for example, the resistive layer 110 is formed on the flexible substrate 100 by thick film or thin film process.
[0037] Next, as shown in FIG. 7(B) , a first electrode part 121 and a second electrode part 122 having electrical conductive function located at two opposite sides of a lower surface of the resistive layer 110 are formed by electroplating, press fitting or welding process. Also, in this embodiment, a metal layer 160 is further formed on the flexible substrate 100 . It should be noted, the metal layer 160 is used for increasing the heat dissipation of the resistive device, and it can be removed if need.
[0038] As shown in FIG. 7(C) , the resistive layer 110 is etched to form a recess 111 for adjusting the resistance value of the resistive layer 110 . Also, the metal layer 160 is etched to form a groove 161 , and thus a first metal sheet 162 and a second metal sheet 164 separated with each other are formed.
[0039] As shown in FIG. 7(D) , a first protective layer 140 is formed on the lower surface of the resistive layer 110 between the first electrode part 121 and the second electrode part 122 to prevent the resistive layer 110 from contamination or oxidation. Also, a second protective layer 150 is formed on an upper surface of the flexible substrate 100 to provide enough strength for supporting the resistive device.
[0040] As shown in FIG. 7(E) , a first outer welding layer 126 covering the first electrode part 121 and a second outer welding layer 127 covering the second electrode part 122 are formed to increase the adhesion of the first electrode part 121 and the second electrode part 122 , and to increase the bonding strength between the resistive device and PCB.
[0041] The described embodiments are preferred embodiments of the present invention. However, this is not intended to limit the scope of the invention. The equivalent changes and modifications may be made in accordance with the claims of the invention without departing from the scope of the invention. | A resistive device includes a resistive layer, a flexible substrate arranged on the resistive layer, and an electrode layer. The electrode layer includes two electrode sections arranged below the resistive layer and separate to each other. Moreover, a method for manufacturing the resistive device with flexible substrate is also disclosed. | 8 |
This is a divisional application of the C. W. Schaible application, Ser. No. 959,095, filed Nov. 9, 1978, and now U.S. Pat. No. 4,229,620.
BACKGROUND OF THE INVENTION
This invention relates to mobile radiotelephone systems and particularly to such systems which employ a tone for supervision of call status.
Cellular radio communication systems are being increasingly considered as arrangements which can allow substantially higher numbers of mobile radiotelephone subscribers to have access to a relatively limited number of radio communication channels. One form of such a cellular system is described in a report entitled High Capacity Mobile Telephone System Technical Report, December 1971, prepared by Bell Telephone Laboratories, Incorporated, and filed with the Federal Communications Commission in that month under Docket 18262. It has been proposed in such a cellular radio system to require each base station, sometimes called a cell site, which communicates on a set of channels in common with other base stations that are within a potential cochannel interference radius, to combine with its access, or call setup, channel signals a supervisory tone which is unique to that base station among the group of possibly interfering base stations. Such a tone is transponded by a mobile unit receiving that channel. Any base station receiving the transponded tone employs it to determine whether or not the transponding mobile station has been captured by an interfering base station and whether or not the receiving base station has captured an interferring mobile station. In this context the term "captured" is utilized with reference to the well-known phenomenon of frequency modulation capture. Three examples of cellular mobile radiotelephone systems are found in the U.S. Pat. Nos. 3,663,762 of A. E. Joel, 3,898,380 of G. D. Wells et al., and 3,906,166 of M. Cooper et al.
It is desirable in the cellular type of system to provide some indication of the location of a mobile unit engaged in a call connection in the system. The patentees in the three aforementioned patents all employ some form of signal level determination as an indication of mobile unit position so that a decision can be made as to when to handoff a mobile unit between adjacent cell base stations. However, the aforementioned supervisory tone is also useful for propagation delay ranging as indicated for example at page 3-17 in the aforementioned technical report. Another propagation delay system is indicated at page 4-64 of "An Application for a Developmental Cellular Mobile and Portable Radiotelephone System in the Washington-Baltimore Northern-Virginia Area". This application was submitted to the Federal Communications Commission by the American Radio Telephone Service, Incorporated and dated Feb. 14, 1977.
Propagation delay ranging, or phase ranging as it is sometimes called, is accomplished in the mentioned technical report by utilizing one of plural system supervisory tones near the upper end of the voice band and which are usually very close together in the frequency spectrum, e.g., within about ±0.5% of one another. Any use of the supervisory audible tone, including its use for ranging, requires a receiving station to determine that it is receiving the true tone for its channel. Detection of a certain one of several such closely spaced tones by conventional filtering techniques usually requires complex and/or difficult-to-integrate circuits. Another technique that has been proposed, for example, in the E. J. Addeo, U.S. Pat. No. 4,025,853, depends upon product modulating a transponded version of the tone, after selection by a phase-locked loop, with a transmitted version of the tone. Then the modulator output is bandpass filtered in a band including the possible difference frequencies among the system supervisory tones. If no such difference frequency is detected, it is presumed that the correct supervisory tone is being received. If such a difference frequency is detected, it is presumed that the wrong supervisory tone is being received, i.e., that interference is present from another usage of the same channel in the system, and a call in progress is terminated. It has been found that reflections from topological features can cause multipath sidebands in the difference frequency band at the modulator output and of sufficient amplitude to cause call termination even when the correct supervisory tone is present.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, a predetermined tone is derived from a received signal in which the predetermined tone is one of plural tones spectrally spaced from one another by narrow bands much smaller in frequency than the tones themselves, the received signal is used to produce, for a correct signal, a predetermined control tone of a frequency that is of approximately the same order of magnitude as the spacing bandwidth. That control tone is readily selectable from erroneous control tones resulting from other ones of the plural tones of incorrect signals.
BRIEF DESCRIPTION OF THE DRAWING
A more complete understanding of the invention may be obtained from a consideration of the following detailed description together with the appended claims and the attached drawing in which
FIG. 1 is a diagram of cells and channel assignments indicating channel reuse in a previously proposed radiotelephone communication system;
FIG. 2 is a simplified functional diagram indicating potential multipath interference and cochannel interference paths among radiotelephone units; and
FIG. 3. is a simplified block and line digram of cell base station equipment utilizing the invention for the detection and utilization of supervisory audible tones in the system of the type illustrated in FIGS. 1 and 2.
DETAILED DESCRIPTION
FIG. 1 illustrates a part of a honeycomb type of cellular overlay on a mobile communication area for defining approximately the principal communication subareas associated with respective sets of radio frequency channels. Although the term "mobile" often connotes a motor-vehicle-mounted unit, the term is not so restricted and can embrace any portable radio station.
In the center of the honeycomb arrangement of hexagonal cells in FIG. 1 is a set of seven cells numbered 1 through 7. Each of those seven cells is assigned a different set of communication channels. For present purposes, it is immaterial whether each cell has a centrally located omnidirectional antenna system or each cell has a directional antenna system with antennas located, for example, at respective alternate corners of each hexagonal cell representation.
Surrounding the central set of cells in FIG. 1 is a ring of six further cell sets, each having the same overall channel set as does the aforementioned central cell set, although only the upper left-hand cell in each set of the ring is numbered with the numeral "1" to facilitate cell set location. Additional cell sets can be added in any direction as may become necessary to suit the needs of the radiotelephone traffic to be handled. It has been found that there usually is no significant cochannel intereference between cells using the same set of channels in this arrangement because cells in which a common channel set is reused are not closer to one another than a distance of D units, approximately the diameter of a cell set, for a cell radius of R units, and wherein the ratio D/R equals approximately 4.6 for the seven-cell hexagonal grid of FIG. 1. Stated differently, the cells are advantageously proportioned and operated so that a signal-to-interference ratio of at least 17 dB prevails over at least 90% of the cell area. Such a ratio allows the frequency modulation capture effect to suppress an otherwise interfering signal.
Of course, various events can cause signal fades or surges that can result in cochannel interference. Thus, Rayleigh fading, produced as a mobile station is moved, can cause brief bursts of such interference. Also, shadow effects caused by a mobile station passing behind, with respect to its base station, some topological formation such as a hill or a building can also cause fading. In addition, the peaking effect produced by a mobile station passing over the top of a high hill can produce a signal surge of significant duration. It has been found that higher channel utilization results if cell patterns need not be so large as to prevent all cochannel interference in spite of the aforementioned signal fading and surging types of occurrences.
In FIG. 2 there are shown two base stations: a nearby station 10 and a remote base station 11 which are both utilizing the same communication channel as schematically represented in the block in the drawing by the term "Channel A" for each base station. The term "base station" is here used to indicate all channel transmitters and receivers of radio energy as well as the equipment located at the same site for utilizing them. Such totality is sometimes in the literature called a cell site. A mobile telecommunication switching office (MTSO) 14 is connected to each base station by a separate circuit for each channel at that station. All of the separate circuits are schematically represented by a cable extending from the MTSO to each base station. These two base stations are assumed to be a distance D apart in different cell sets as hereinbefore indicated with respect to FIG. 1. Accordingly, although both stations are utilizing the same communication channel, each has a different supervisory audible tone (SAT) modulated on its respective transmissions in that channel.
Also shown in FIG. 2 are two mobile units 12 and 13 which are located in the cells of, and for primary communication with, the base stations 10 and 11, respectively, as schematically represented by the solid jagged lines extending between antennas. However, due to some signal fading or surging phenomena, such as those of the type hereinbefore mentioned, the mobile units 12 and 13 may also find themselves in at least limited communication with the base stations 11 and 10, respectively, as indicated by the broken jagged lines extending between the antennas of unit 12 and station 11 and between the antennas of unit 13 and station 10.
For example, a signal fading condition of some kind may cause the mobile unit No. 12 to capture transmission from the base station 11 instead of that on the same channel from the base station 10 even though the mobile unit No. 12 is still being adequately heard by the base station 10. In the latter circumstance, the mobile unit No. 12 will transpond the SAT of base station 11 and the nearby base station 10 will detect the lack of SAT verification in the transmission from mobile unit 12. Alternatively, the aforementioned fading condition with respect to mobile unit No. 12 may not result in its capture of the remote base station transmission 11, but it may enable the nearby base station 10 to capture transmissions from the mobile unit 13 even though the latter unit is still being adequately received by the remote base station 11. Here again, the nearby base station 10 would also detect a lack of SAT verification on its channel A.
The cochannel interference indicated by the lack of SAT verification in a station can indicate the presence of conditions which result in annoyance to radiotelephone subscribers during short interference bursts. In addition, if the lack of SAT verification continues long enough, a loss of supervision may result causing erroneous termination of a call in process.
Also shown in FIG. 2 is a building 15 which schematically represents any building or other topographical or atmosheric situation causing relfections of radio signal transmissions between, for example, the mobile unit 12 and the base station 10. Such a reflection path is represented in FIG. 2 by the jagged dash-dot lines extending from the mobile unit antenna to the building 15 and then to the antenna of the base station 10. As previously noted herein, such a reflection path signal arrives at the base station 10 antenna in a different phase relationship from the transmission directly to the antenna from the mobile unit 12, and the resultant phase dispersion causes the station's frequency modulation discriminator for the channel to produce sidebands within about ±10 Hz of any SAT to complicate the determination of the correct SAT and thereby the determination of mobile unit range.
FIG. 3 shows block and line circuits for detecting a correct SAT and using the detected SAT for determining the range between two radio stations. The circuits of FIG. 3 are shown and described in terms of equipment located at a fixed station, such as the station 10 in FIG. 2; but the system could equally well be arranged to have the equipment of FIG. 3 located in a mobile unit. Individual circuit components shown in FIG. 3 are all known in the art and details thereof comprise no part of the present invention.
A common antenna 20 is schematically used to indicate both transmitting and receiving antenna functions for the equipment. A controller 21 determines cell site equipment operation in the station 10 in accordance with operating procedures of a type which are now known in the art. These procedures include exercising control over the operation of a channel transmitter 22 and a channel receiver 23 and their associated circuits. The controller 21 further includes a data modulator and demodulator designated "modem" for such data communication as is required to take place among a mobile unit, the base station, and the mobile telecommunication switching office (MTSO) 14. All the circuits in FIG. 3 other than the antenna, the controller 21, and a local SAT signal source 26 are duplicated for each channel at the cell site but only the single set shown in FIG. 3 need be considered for understanding the invention. The channel equipment is the same for each channel at the base station.
The transmitter 22 receives call voice signals from the MTSO and modulates those signals along with a SAT frequency f SAT from a SAT signal source 26 onto a transmission carrier for the channel. Data from the MTSO is transmitted to the base station on circuits (also in the mentioned cables to respective base stations) which are separate from the voice circuits and are applied to the modem in the controller 21. Those data signals which are intended for the mobile unit for a particular channel are applied by way of a circuit 27 to the transmitter 22 of that channel. The transmitter is turned on and off in accordance with a predetermined operating program as directed by a transmitter control signal XMTR CONT from the controller 21.
The receiver 23 is a frequency modulation receiver and provides from its discriminator output after filtering the call voice signals on a circuit 28 to the MTSO. The receiver also provides the voice and SAT signals to a filter-limiter 29 which is common to circuits to be described for providing detection of the presence of the correct SAT for the fixed station cell site and for processing received signals to determine the range out to the mobile unit which transmitted those signals. Data contained in received signals in receiver 23 is supplied to the controller 21 by way of a circuit 30.
Filter-limiter 29 receives signals including voice and SAT and advantageously includes two stages of integrated circuit amplifiers such as, for example, the Western Electric 502AR amplifier chips and their respective associated resistors and capacitors to provide the desired characteristics. Thus in one embodiment, the input filter stage advantageously reduces voice frequency energy below 3000 Hz to a level below that of energy around 6000 Hz and passes tones in a band at a frequency of about 6000 Hz which includes all of the SATs of the system. A second, or limiter, stage is arranged to provide a noise limiting function for preventing overdrive to circuits 32 and 39 to be described.
A branch circuit 24 in FIG. 3 processes received signals to indicate whether or not correct SAT is present. An oscillator 31 is advantageously a crystal oscillator which is operated at a frequency (f SAT +Δf) which is the sum of the SAT frequency for the base station using the equipment of FIG. 3 plus a predetermined lower frequency Δf. The frequency Δf is selected to have a value which is much lower than the f SAT tone and which is substantially different from the frequency spacing between adjacent SATs. In one illustrative embodiment, a frequency Δf of 100 Hz was employed for a system having SATs in the 6 kHz range.
The received signals from filter-limiter 29 and a local reference frequency signal from the oscillator 31 are applied to the two inputs, respectively, of a product modulator such as the Motorola MC1496 modulator chip and its associated resistors and capacitors arranged to cause the modulator to operate in a down converting mode. In such a mode the modulator performs a linear mixing to produce the sum and difference frequencies from the two input signals applied thereto. A low pass filter 33 couples the output of modulator 32 to the input of a phase-locked loop tone detector 36. Filter 33 advantageously has a cutoff frequency of about 150 Hz for a system employing a Δf frequency of 100 Hz.
The tone detector 36 is configured to respond to the Δf frequency with a tolerance range which is much less than the spectral spacings between the desired SAT and either of the possible adjacent system SATs or their respective multipath sidebands. The output signal of the tone detector 36 is a logic level signal of a predetermined minimum amplitude when the correct SAT is being provided in the voice signals from the filter-limiter 29. Thus, it is within the skill of the art to use, for example, either the Western Electric Company 502ER phase-locked loop chip or the EXAR Integrated Systems phase-locked loop chip EXAR2211 with their respective associated resistors and capacitors for enabling the loop to select the Δf tone required for the station with a tolerance of approximately ±4%. In such an arrangement, for example, for a station having an assigned SAT of 5970 Hz, the tone detector 36 rejects outputs from the filter 33 of 40 Hz (in regard to a SAT of 6030 Hz) or 70 Hz (in regard to a SAT of 6000 Hz). Also rejected are other frequencies (usually within a range of about ±10 Hz from either of those 40 or 70 Hz tones) which represent difference frequencies resulting from multipath sidebands around the 6030 Hz and 6000 Hz tones as applied from the filter-limiter 29.
Tone detector 36 output of the indicated minimum logic level sets a flip-flop circuit 37 to provide a DET SAT signal to controller 21 indicating that the correct SAT is present. This enables the controller to use that information in accordance with the usual station operating procedures. Output from the detector 36 is also applied to an input of a timer 38 for automatically resetting the flip-flop 37 after a predetermined interval following loss of the correct SAT, i.e., loss of the predetermined minimum amplitude indicator signal from the detector 36. The minimum interval is set by system requirements at a level which is the longest interval tolerable for radio link fade of sufficient depth to cause loss of accurate SAT reception. An interval of 175 milliseconds, ±25 milliseconds, was found to be suitable for one embodiment of the invention in a cellular radio system.
The function of the timer 38 can be provided by means of a monostable multivibrator. However, the 175 millisecond interval is rather long in some senses and thus may require a rather large timing capacitance for the monostable multivibrator and large capacitances are sometimes hard to implement in integrated semiconductor technology. Alternatively, an oscillator-counter combination is advantageously employed to the same effect, i.e., the oscillator is triggered into activity upon loss of the output signal from the detector 36 and begins to drive the counter in the chip. If the detector output is shortly restored, the oscillator is reset and no output is provided from the timer 38. However, if the detector output is lost for at least the indicated minimum interval, the counter is driven to a predetermined count level corresponding to that interval and provides an output for resetting the flip-flop 37 as already mentioned. One oscillator-counter chip is the Western Electric Company 41 HK oscillator/counter delay integrated circuit chip which is coupled to associated resistors and capacitors to provide the delay operation in the manner just outlined.
The ranging processing of the received signals is accomplished in a branch circuit 34 in FIG. 3 by a two-way ranging propagation delay technique wherein a comparison is performed between the phase information contained in a reference signal, such as the locally generated SAT from the source 26 which is transmitted on the transmission channel, and the phase information in the SAT of a received signal, such as the SAT transponded by a remote mobile unit and received with the voice signals back at the base station receiver 23. The comparator output in such an arrangement is then integrated to provide an output signal magnitude which is indicative of the required range information as will be described. The received signal from the filter-limiter 29 is coupled to the phase ranging branch circuit 34 of the FIG. 3 circuit at an input to a phase-locked loop 39. The phase-locked loop 39 detects signals in the SAT band and reconstructs a tone which it finds there. For correct operation, that tone will be the transponded tone from the mobile unit engaged in a call on the channel being served through the base station circuits illustrated in FIG. 3. Thus, for the indicated SATs a signal selection in the band of 6000 Hz±4% is readily within the skill of the art and prevents interference from voice signals and call progress tones. For example, a Western Electric Company 502EP phase-locked loop integrated circuit chip and its associated resistor and capacitor circuits, or a Motorola NLN565C phase-locked loop chip with its associated resistors and capacitors, will readily perform in the manner just outlined. An output of the phase-locked loop 39 is applied to a clock input of a D-type flip-flop circuit 40, and the Q output of that flip-flop circuit is applied to one input of an EXCLUSIVE OR logic gate 41.
The transmitted SAT from the source 26 is coupled through an EXCLUSIVE OR gate 42 and a delay circuit 43 to the clock input of a further D-type flip-flop circuit 46. A second input to the EXCLUSIVE OR gate 42 is provided through a selection switch 47 from either ground or a positive potential, depending upon the position of the switch, so that the gate can couple the SAT in either its true form or with a 180-degree phase shift for a purpose to be described. The amount of delay provided by delay circuit 43 is advantageously continuously manually adjustable over a range of about 180 electrical degrees for signals in the illustrative SAT band around 6000 Hz. This manual adjustment is schematically represented in FIG. 3 by the variable resistor 48 included in the schematic representation of the delay in the drawing. Thus, switch 47, gate 42, and the adjustable resistor 48 together allow substantially full 360 electrical degrees of phase adjustment. That capability advantageously employed for calibration of the circuits of FIG. 3 to provide a zero-range output signal level on a RANGE output lead 49 for a mobile unit located as close as practical to the base station antenna 20.
The Q output of the flip-flop circuit 46 is coupled back to the data, or D, input of the same flip-flop circuit. The Q output of the flip-flop 46 is coupled to the D input of the flip-flop 40 as well as to a second input on the EXCLUSIVE OR gate 41. Delay circuit 43 is made up advantageously of two tandem connected monostable multivibrators. The first of the two has the adjustable resistor 48 connected in its timing circuit for adjusting the interval between triggering and automatic reset. The second of the two monostable multivibrators responds to the output of the first on reset to provide a narrow but clean, steep-sided pulse of usually less than 50% duty cycle for clocking the flip-flop circuit 46 at the time indicated by the delayed SAT pulse. Outputs of the flip-flop circuits 40 and 46 are both symmetrical square waves. The lead 50 coupling the Q output of flip-flop 46 to the data input of flip-flop 40 forces the latter flip-flop to operate approximately in step with the former flip-flop but as clocked from the phase-locked loop 39. One cannot forecast in which state each flip-flop will begin to operate when the circuit is first powered up or, for flip-flop 40, after any arbitrary input signal interruption of signal from loop 39. However, lead 50 forces the states of flip-flop 40 to track those of flip-flop 46 with a phase difference specified by the clock signals from loop 39. Thus, the two flip-flop circuits cannot remain out of track with one another beyond a brief get-into-step interval and thereby provided erroneous ranging indications as a result of a possible 180-degree phase ambiguity between their outputs.
As earlier noted, the EXCLUSIVE OR gate 41 operates as a phase comparator with respect to the Q outputs of the flip-flop circuits 40 and 46. The output of EXCLUSIVE OR gate 41 is, therefore, high when its two input signal states are different, i.e., of different polarities; and it is low when those two inputs are the same, i.e., of the same polarity.
In phase ranging systems, the measurable range is a function of the electric wavelength of the signal used for the ranging operation. For SAT signals in the 6 kHz range, i.e., a wavelength of 31 miles, a vehicle range (1/2 the sum of the round trip transmission and return distances) of about 15 miles is conveniently measurable by phase comparison. There is, however, a phase ambiguity beyond the first half wavelength distance of about 7.5 miles because the EXCLUSIVE OR type of phase comparator is sensitive to input signals having the same polarity or having different polarities but without reference to which half cycle of any signal wave is involved. This causes some trouble in systems with, for example, 8 miles radius cells. This difficulty is resolved by dividing the frequencies of the compared signals, e.g., by dividing those frequencies by two in the illustrative embodiment using flip-flop circuits 40 and 46. Then on the frequency divided signal a 180-degree half wave portion is equivalent in wavelength to a full cycle of the SAT of the received wave, and the ambiguity thus disappears.
The output of EXCLUSIVE OR gate 41 controls one section of an analog switch 51 wherein the switch section is schematically represented by a mechanical switch 52 but is in actuality advantageously a field effect transistor switch. By controlling the switch section 52, the output of EXCLUSIVE OR gate 41 selects one of two different input drive bias signals for an integrator circuit 53 including a series resistor 56 and a shunt capacitor 57. The bias signal thus selected is coupled through a switch section 58 of the same switch 51 to the integrator 53. The bias sources are provided, for example, from a potential dividing arrangement including four resistors 59 through 62 connected in series between ground and a positive voltage supply 63 schematically represented by a circled positive sign to indicate a supply having its other terminal connected to ground. The upper terminal of switch 52 is connected to the dividing arrangement at a lead 54 between resistors 59 and 60 to provide, for example, a voltage of approximately 7.6 volts and similarly the lower terminal of the switch 52 is connected to the dividing arrangement at a lead 55 between resistors 61 and 62 to provide a voltage of approximately 0.8 volts. Those two voltages represent the maximum and minimum, respectively, output voltages available from the integrator circuit 53. The maximum voltage value represents maximum range, i.e., about 15 miles in the illustrative embodiment and the minimum voltage value represents a level near, but not exactly equal to, the minimum range, or zero range, value for a reason to be subsequently described. The employment of the indicated potential dividing arrangement advantageously utilizing a regulated supply and 1% precision resistors makes the integrator circuit input bias signals independent of chip-to-chip variations in the circuit elements of the phase comparing EXCLUSIVE OR gate 41. One switch suitable for the analog switch 51 is the AD7512KN analog switch made by the Analog Devices Corporation.
The output of the integrator 53 is coupled to a noninverting input of an amplifier 66 which is advantageously arranged to operate as a voltage follower. This amplifier, one form of which is advantageously the LF356 amplifier of the National Semiconductor Corporation, has its output coupled back to an inverting input of the amplifier and also coupled through a switch section 67 of another analog switch 68 to provide a RANGE signal on the lead 49 to the controller 21. Switch 67 is controlled by a PHASE SELECT signal provided from the controller 21. Normally a positive voltage from a supply 69 is applied through a resistor 70 to hold the switch 67 open in the absence of the PHASE SELECT signal. Thus, the latter signal when it appears causes the output of amplifier 66 to be sampled as the RANGE signal.
When the channel transmitter 22 is on, a transmitter control signal XMTR CONT operates another switch 71 in the analog switch 68 to the open condition. However, when the transmitter is off, the XMTR CONT signal closes switch 71 in the fashion illustrated in FIG. 3 for putting a low intermediate bias on the off-ground terminal of the integrator circuit capacitor 57. This action dumps any prior charge that had been on that capacitor and clamps the capacitor to a predetermined low voltage level very near to the minimum range voltage previously described. Accordingly, the integrator 53, when so biased, is in a condition to adapt rapidly to any new input signals applied thereto when the transmitter 22 resumes operation.
In the illustrative embodiment, the mentioned intermediate bias level is advantageously close to the minimum, e.g., 1.2 volts for a system wherein the minimum voltage is 0.8 volts. That 1.2 volt value is advantageously considered to be the zero-miles range indication so that on initial calibration of the channel circuits variable resistor 48 in the delay 43 is operated to set the output of the integrator circuit 53 to 1.2 volts and thereby allow a 0.4 volt range below that value in which to work for establishing the zero-miles calibration. With this arrangement, the calibration is effected by a continuous adjustment of the resistor 48 to close in on the 1.2 volt value. Absent this kind of arrangement, i.e., if 0.8 volts were the zero-mile level, any overshoot during adjustment would allow the indication to snap back and forth between the 0.8 level and the 7.6 volt level as the measured phase difference shifted, e.g., between small leading and lagging values.
Radio frequency fades present a pervasive problem in mobile radiotelephone systems as already noted. During a prolonged fade, the phase-locked loop 39 may lose the SAT and the EXCLUSIVE OR gate 41 may then see a relatively continuous large phase difference and cause the integrator circuit 53 to be driven erroneously to a high level indication. This situation is avoided by utilizing a lead 72 for coupling the output of phase-locked loop tone detector 36 to control the section switch 58 in analog switch 51 to maintain that switch closed, as illustrated, during proper reception of the predetermined SAT signal. However, during a fade when that SAT is lost, the switch 58 is operated to its open circuit condition to present the integrator circuit 53 with a very high input impedance. That holds integrator operation at whatever level had just been attained, subject of course to whatever leakage takes place through either that high impedance open switch condition or the high impedance at the input to the amplifier 66. At the end of the fade, the signal on lead 32 closes the switch 58 once more; and normal integration operation resumes.
In mobile radiotelephone systems, when a call signal level deteriorates toward a limiting transmission condition, e.g., due to distance from the base station or shadowing by a topographical feature, the voice transmission can break up and be difficult to understand. However, it has been found that the intermittent spurts of adequate signal are sufficient to continue good ranging operation in circuit 34 because integration is prevented between those spurts by the signals coupled by lead 72. Thus, if the system takes signal strength samples during spurts of adequate signal strength, it can get a false picture of call signal quality; but the continuing accurate range information can show whether or not the mobile unit is about to pass into a different cell.
Although the present invention has been described in connection with a particular embodiment thereof, it is to be understood that other embodiments, modifications, and applicatons thereof which will be apparent to those skilled in the art are included within the spirit and scope of the invention. | Some cellular mobile radiotelephone systems use tones for certain call connection supervisory functions on radio links. The presence of the correct tone in a received radio channel call signal is determined by using the received signal for producing (32) a lower frequency tone that is readily selectable (36) from similar tones produced in response to incorrect supervisory tones. Circuits are also shown for separately processing received call signals to produce (41, 53) supervisory tone phase information that is indicative of range between communicating stations. Several circuits (72; 40 and 46; 59-62) are shown for enhancing the accuracy of the produced phase information of the correct tone. | 7 |
FIELD OF THE INVENTION
The present invention relates to the field of semiconductors and more particularly to an apparatus and method for mitigating leakage current in a semiconductor device before catastrophic leakage current runaway occurs. It should be understood that while the apparatus and method of the invention described herein relate to semiconductor devices generally, specific emphasis is placed on the present invention's application to metal oxide semiconductor field effect transistor (MOSFET) devices.
BACKGROUND OF THE INVENTION
Leakage current runaway is a catastrophic phenomenon that occurs in MOSFET devices during dormant mode when a MOSFET device is biased with full operating voltage (Vdd) across source and drain nodes while gate voltage is switched off. Normally, the leakage current in a dormant MOSFET device does not change with time. However, if the device channel length is sufficiently short, the leakage current, especially the drain induced barrier lower (DIBL) leakage current, will increase over time. In such cases, this DIBL current can possess enough energy to cause impact ionization inside the transistor channel and damage the device, resulting in a decrease in threshold voltage. A lowered threshold voltage prompts a further increase in DIBL leakage current, and subsequently, a chain reaction takes place with a positive feedback that eventually results in leakage current runaway.
Leakage current runaway is becoming a serious concern due to the ever increasing use of very short channels and extended dormant mode in high speed designs. The details of the leakage current runaway mechanism have been reported in a paper titled “Degradation and Recovery of NMOS Subthreshold Leakage Current by Off-state Hot Carrier Stress” in 2006 ICCDCS. As discovered by the authors of this paper, the increase of the leakage current can be recovered by switching devices from dormant mode into active mode for a short period of time.
SUMMARY OF THE INVENTION
The embodiment of the invention broadly and generally provides a semiconductor circuit for mitigating leakage current, comprising:
at least one leakage current target unit comprising a target semiconductor device connected to a first switch control logic device, the aforesaid target semiconductor device being in a dormant mode;
a current shift monitor unit connected to the aforesaid leakage current target unit, the aforesaid monitor unit to collect leakage current from the aforesaid target semiconductor device for two consecutive predefined temporal periods, to convert the two collected leakage currents to two corresponding voltages, and measure the voltage difference therebetween;
a reference voltage generator that outputs a voltage signal used as a reference to define a critical shift in leakage current;
a comparator which receives the outputs of the current shift monitor unit and the reference voltage generator, the aforesaid comparator being configured to compare the aforesaid voltage difference from the aforesaid current shift monitor unit and the aforesaid reference voltage generator and to propagate an alert signal to the leakage current target unit when the leakage voltage output from the aforesaid current shift monitor unit exceeds the reference voltage;
a repair voltage generator which outputs a repair voltage to the aforesaid first switch control logic device, the aforesaid repair voltage being applied from the aforesaid first switch control logic device to the gate of the target semiconductor device in response to the aforesaid alert signal from the aforesaid comparator, the aforesaid alert signal thereby causing the aforesaid target semiconductor device to switch to an active mode for repair.
According to a preferred embodiment, the aforesaid current shift monitor unit comprises:
a second switch control logic device to receive leakage current from the aforesaid target semiconductor device;
at least two charge collecting devices connected to the aforesaid second switch control logic device, each of the aforesaid charge collecting devices being operable to alternately receive integrated current during at least the aforesaid two consecutive predefined temporal periods of time and to convert the charge to a voltage;
a differential amplifier connected to the aforesaid charge collecting devices, operable to receive voltages therefrom, the aforesaid differential amplifier further being operable to compare any change in voltages for the aforesaid consecutive periods and to output a first differential voltage between the aforesaid voltages of the aforesaid charge collecting devices to the comparator.
According to another preferred embodiment, the aforesaid current shift monitor unit further comprises:
a polarity switch connected to the aforesaid differential amplifier that reverses the polarity of the differential amplifier following the aforesaid comparison between the aforesaid voltages from the aforesaid charge collecting devices to thereby supply a second differential voltage output to the comparator.
According to another preferred embodiment, the aforesaid leakage current target unit, the aforesaid current shift monitor unit, the aforesaid reference voltage generator, the aforesaid comparator, and the aforesaid repair voltage generator are disposed on a single substrate of semiconductor material.
Preferably, the aforesaid target semiconductor device is a MOSFET and the aforesaid comparator is an op amp.
According to another preferred embodiment, the aforesaid voltage signal from the aforesaid reference voltage generator is an integer multiple of the aforesaid voltage difference from the aforesaid current shift monitor unit.
Preferably, the aforesaid repair voltage is between a threshold voltage for the target semiconductor device and an operating voltage for the aforesaid target semiconductor device.
According to another embodiment of the invention, the aforesaid semiconductor circuit further comprises a plurality of leakage current target units which are individually selected for leakage current measurement and mitigation via a multiplexer.
Preferably, the aforesaid plurality of leakage current target units are sequentially selected for leakage current mitigation.
According to another preferred embodiment, the aforesaid plurality of leakage current target units, the aforesaid current shift monitor unit, the aforesaid reference voltage generator, the aforesaid comparator, and the aforesaid repair voltage generator are disposed on a single substrate of semiconductor material.
Another embodiment of the invention also provides a method for detecting and mitigating leakage current runaway on a target semiconductor device, the method comprising:
collecting leakage current from a dormant target semiconductor device for two consecutive predefined temporal periods;
converting the two collected leakage currents to two corresponding voltages;
measuring the voltage difference between the aforesaid two corresponding voltages;
providing a reference voltage to define a critical shift in the leakage current;
comparing the aforesaid reference voltage with the aforesaid voltage difference;
submitting an alert signal in response to the aforesaid voltage difference exceeding the reference voltage; and
submitting a repair voltage to the gate of the target semiconductor device to mitigate current leakage in the aforesaid target semiconductor device in response to the aforesaid alert signal.
According to another preferred embodiment, the aforesaid collection of leakage current from a dormant target semiconductor device for two consecutive predefined temporal periods further comprises distributing the leakage current to two charge collecting devices which are operable to alternately collect current for two consecutive predefined temporal periods of time.
According to another preferred embodiment, the aforesaid measuring of the voltage difference between said two corresponding voltages further comprises using a differential amplifier to receive voltages from the aforesaid two charge collecting devices, to thereby output the aforesaid voltage difference to a comparator.
According to another preferred embodiment, the aforesaid measuring of the voltage difference between said two corresponding voltages further comprises the use of a polarity switch connected to the aforesaid differential amplifier to reverse the polarity of the differential amplifier after the aforesaid output of the aforesaid voltage difference and to thereby provide a second voltage difference to the comparator.
Preferably, the aforesaid method is performed on a MOSFET semiconductor device.
Preferably, the aforesaid repair voltage is between a threshold voltage for the target semiconductor device and an operating voltage for the aforesaid device.
According to another embodiment, the aforesaid reference voltage is an integer multiple of the aforesaid voltage difference.
Preferably, the aforesaid reference voltage is twice the aforesaid voltage difference.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the invention will be more clearly understood from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
FIG. 1 is a graphical plot of a leakage current change for a semiconductor device during a dormant state;
FIG. 2 is a block diagram of a semiconductor circuit for mitigation of leakage current for a single semiconductor device according to an embodiment of the invention;
FIG. 3 is a block diagram of a leakage current target unit containing a switch control logic device and target semiconductor device according to an embodiment of the present invention;
FIG. 4 is a block diagram of a leakage current shift monitor unit according to an embodiment of the present invention;
FIG. 5 is a schematic circuit diagram of the block diagram shown in FIG. 2 according to an illustrative embodiment; and
FIG. 6 is a block diagram of a semiconductor circuit for mitigation of leakage current for multiple semiconductor devices according to another illustrative embodiment.
DETAILED DESCRIPTION OF THE INVENTION
One or more embodiments of the invention provide a method and circuit for detecting and mitigating leakage current shift in a semiconductor device, particularly in a MOSFET device, before catastrophic leakage current runaway occurs.
As shown in FIG. 1 , a charge (Q) due to leakage current in a target semiconductor device in a leakage current target is collected for a plurality of discrete temporal periods (Δt). According to a sample embodiment, the semiconductor device is a MOSFET device in dormant mode. During a first temporal period t 1 , a second temporal periods t 2 , and a third temporal period t 3 , the charge due to leakage for each temporal period is not significantly different from one temporal period to the next (i.e., less than about 25% change) so there is no significant leakage current shift. During a fourth temporal period t 4 , however, the charge Q due to leakage current is significantly larger than during the previous temporal period t 3 (i.e., greater than 200% change). During a fifth temporal period t 5 the charge Q due to leakage current increases exponentially over the previous temporal period t 4 as runaway leakage current occurs. Thus, there is a significant shift in leakage current due to the charge Q increases (between the third and fourth temporal periods in the illustrated example), which is a precursor to leakage current runaway.
In accordance with one embodiment of the invention, the charges collected during two consecutive temporal periods (n) and (n+1) are stored as voltage potentials V(n) and V(n+1), respectively, on current to voltage conversion devices, such as a capacitor. A difference between the voltages for consecutive temporal periods (V(n+1)−V(n)) is determined using such current to voltage conversion devices.
A reference voltage Vref is used to identify critical differences in voltage provided by the charge Q between consecutive temporal periods sufficient to cause leakage current shift which is a precursor to leakage current runaway. The reference voltage Vref, which is submitted by the reference voltage generator, may be either a fixed voltage or may be a function of the charge Q for an earlier one of two consecutive temporal periods. For example, the reference voltage Vref may be a multiple of the voltage for the earlier of two consecutive temporal periods (mV(n)). More specifically, according to an illustrative embodiment, the reference voltage Vref may be equal to twice the voltage for the earlier temporal period (2V(n)).
FIG. 2 is a block diagram of one embodiment of the invention, in the form of a circuit 100 for detecting and mitigating leakage current shift in a semiconductor device, such as a MOSFET device during dormant mode. As can be seen in FIG. 2 , circuit 100 comprises a leakage current target unit 10 , a current shift monitor unit 20 , a reference voltage generator 30 , a comparator 40 , and a repair voltage generator 50 .
To detect the onset of leakage current runaway, the difference in voltages for consecutive temporal periods is compared to the reference voltage. A leakage current shift from the leakage current target unit 10 is detected when the difference in voltage for consecutive temporal periods is greater than the reference voltage, as represented by the following equation:
[ V ( n+ 1)− V ( n )]> V ref (eq. 1)
In the present invention, the leakage current shift indicating an imminent leakage current runaway is mitigated by applying a repair voltage Vfix to the control node of a target semiconductor device, for example, to the gate of a MOSFET device while concurrently switching the target semiconductor device from a dormant to an active mode. According to one embodiment, the repair voltage Vfix is a voltage having a magnitude between a threshold voltage for the MOSFET device and an operating voltage for the MOSFET device. It should be noted that the threshold voltage and operating voltage are characteristic properties of a MOSFET device and are readily obtainable.
As can be seen in FIG. 3 , the current shift monitor unit 20 is electrically connected to the target semiconductor device 14 , so that leakage current from the target semiconductor device 14 flows into the current shift monitor unit 20 . The current shift monitor 20 collects the charge due to leakage current for consecutive temporal periods and converts the leakage currents into corresponding voltages. The current shift monitor unit 20 monitors the leakage current from the target semiconductor device 14 by measuring any difference or shift in the voltages during said consecutive temporal periods. The current shift monitor unit 20 provides an amplified signal of the voltage difference (AΔV) over consecutive temporal periods due to a leakage current shift as an output.
A reference voltage generator 30 produces a voltage signal (Vref) which is used as a threshold to define a critical shift in the leakage current. The reference voltage Vref may have a fixed voltage value corresponding to a critical shift for the target MOSFET device 14 . Alternatively, the reference voltage Vref may be a function of one of the two voltage values (V(n)) saved by the current shift monitor unit 20 during previous monitoring of leakage current over two consecutive temporal periods. In one embodiment, the reference voltage Vref is a multiple of the earlier of the two voltages (V(n)) measured by the current shift monitor unit 20 at two prior temporal periods. According to an illustrative embodiment, the reference voltage is equal to twice the value of the earlier of the two voltages (V(n)).
The outputs of the voltage difference signal (AΔV) provided by the current shift monitor unit 20 and the reference voltage Vref from the reference voltage generator 30 are input into a comparator 40 , which according to one embodiment is an op amp. The comparator 40 compares the voltage difference signal (AΔV) to the reference voltage Vref. If the voltage difference signal (AΔV) is greater than the reference voltage Vref, then the comparator 40 sends a repair signal Vflag to the leakage current target unit 10 . The presence of the repair signal Vflag applied to the leakage current target unit 10 allows the voltage Vfix from the repair voltage generator 50 to mitigate the leakage current runaway of the target semiconductor device 14 by switching it from a dormant to active state.
FIG. 3 is a block diagram showing the leakage current target unit 10 of the circuit 100 ( FIG. 2 ) comprising a MOSFET device or other target semiconductor device 14 in dormant mode to be monitored for leakage current shift and a first switch control logic device 12 to mitigate leakage current runaway. The first switch control logic device 12 will be subsequently explained in more detail, but it essentially switches the repair voltage Vfix from the repair voltage generator 50 to the gate of the target semiconductor device 14 when the signal Vflag is present. The target semiconductor device 14 has an input node, an output node, and a control node. In the following description the target device is a N-type MOSFET device and the input node is a drain, the output node is a source and the control node is a gate, as is known in the art. The present invention encompasses other semiconductor devices as well, including P-type devices where the drain is the output node and the source is the input node. Moreover, the target semiconductor device 14 may be metal on silicon or any other composition within the broader definition of a MOSFET device (i.e. using non-metal conductive lines and contacts, polysilicon, galium arsenide or other semiconductive channel).
In a sample embodiment, the first switch control logic device 12 receives a plurality of input options, selects the appropriate bias conditions, and feeds the selected bias voltage to the target semiconductor device 14 . The voltage Vdd triggers the target semiconductor device 14 to an active mode (i.e. switches the target semiconductor device “on”); ground GND is applied for “dormant” mode (i.e. switches the target semiconductor device to “off” or “standby”); and the repair voltage Vfix in the presence of alert voltage Vflag, which has the effect of switching the target semiconductor device 14 to an active mode, is applied to prevent significant leakage current shift in the target semiconductor device 14 . In response to a control signal for turning a target semiconductor device 14 on, the first switch control logic device 12 switches the operating voltage Vdd to the gate of the target semiconductor device 14 . In response to a control signal for switching the target semiconductor device 14 to a dormant mode, the first switch control logic device 12 switches the ground voltage GND to the gate of the target semiconductor device 14 . In response to an alert or repair signal Vflag from the comparator 40 , the first switch control logic device 12 switches the repair voltage Vfix to the gate of the target device 14 . It should be understood that repair voltage Vfix could alternatively be switched using a separate switching device via the operational and ground voltages.
FIG. 4 , is a block diagram showing the current shift monitor unit 20 in detail according to the present embodiment. The current shift monitor unit 20 comprises a second switch control logic device 22 , two charge collecting devices 241 and 242 , and a differential amplifier 26 with polarity controlled by a polarity switch logic device 28 . In a illustrative embodiment, the charge collecting devices 241 and 242 , are capacitors which convert the leakage current to a voltage potential.
Following is an exemplary embodiment to illustrate the operation of the current shift monitor unit 20 to measure the leakage current from the target semiconductor device 14 . As shown in FIG. 4 , leakage current I(LEAK) flows from the leakage current target unit 10 into a second switch control logic device 22 . The second switch control logic device 22 switches the leakage current I(LEAK) onto a first one of the charge collecting devices 241 , which integrates the leakage current over a period of time Δt between times t 0 and (t 0 +Δt) to generate a voltage V 1 (t 1 ). The first charge collecting device 241 feeds V 1 (t 1 ) to a negative (−) port of a differential amplifier 26 . Then at t 1 the second switch control logic device 22 , in response to time t 1 from a timing circuit or clock, switches the leakage current I(LEAK) from the first charge collecting device 241 to a second charge collecting device 242 . Then from time t 1 to time (t 1 +Δt), the second charge collecting device 242 integrates the subsequent leakage current and generates voltage V 2 (t 2 ) feeding to the positive (+) port of the differential amplifier 26 . With a gain of A, the differential amplifier 26 outputs a voltage of A*(V 2 −V 1 ) or AΔV(t 2 ), to a first port of the comparator 40 , which completes the first leakage current comparison cycle.
The comparator 40 , shown in FIG. 2 , receives the signal AΔV(t 2 ) on a first port and a reference voltage Vref on a second port. According to an illustrative embodiment described previously, the comparator 40 is an op amp that generates a repair signal Vflag for submission to the leakage current target unit 10 if the signal AΔV from the differential amplifier 26 is greater than the reference voltage Vref.
Following the first comparison, the first charge collecting device 241 is discharged and refreshed for the collection of the leakage charges over the next period of time from t 2 to (t 2 +Δt). The accumulated charge on the first charge collecting device 241 at time t 3 generates a voltage V 1 (t 3 ), which is fed to the negative (−) port of the differential amplifier 26 . The polarity of the differential amplifier 26 is then reversed by the polarity switch logic device 28 , so that the polarities at the V 2 (t 2 ) and V 1 (t 3 ) nodes become negative (−) and positive (+), respectively. The output from the differential amplifier 26 then becomes AΔV(t 3 )=A*(V 1 −V 2 ). The differential amplifier 26 outputs the new voltage of A*(V 1 −V 2 ), or AΔV(t 3 ), to a first port of the comparator 40 , which completes the second leakage current comparison cycle.
The same procedure is then repeated continuously in the current shift monitor unit 20 to provide a sequence of voltage output AΔV(tn)=A*(V 2 −V 1 )*(−1) (n+1) that is proportional to the leakage current increase between times tn and t(n+1). Each comparison cycle has duration of Δt. Each time a leakage comparison cycle is completed (i.e. the comparison of output voltages from charge collecting devices, 241 and 242 , over a consecutive temporal period), the charge collecting device having just been charged with leakage current over some period of time is discharged (i.e., the charge collecting device that is connected to the negative node of the differential amplifier). The second switch control logic device 22 then feeds additional leakage current to the mostly recently discharged charge collecting device and the polarity switch logic device 28 subsequently switches the polarity of the differential amplifier 26 . The temporal period Δt or interval for collecting charge due to leakage current is pre-determined for the characteristics and the operating conditions of the device to be monitored, such as voltage and temperature. It may range from about a few seconds to about a few minutes. For a specific circuit, the circuit designers and manufacturers can pre-determine the value Δt based on these characteristics.
It should be noted that the delay between times (tn+Δt) and t(n+1) depends on the switching speed of the control logic, as well as the RC delay of the charge collecting device, and the circuit is designed so that this delay is insignificant compared with the leakage integration time Δt and, therefore, t(n+1)≅(tn+Δt) which will be used thereafter throughout the text to follow.
For detecting the early rise of leakage current, a pre-defined reference voltage Vref is provided by a reference voltage generator 30 shown in FIG. 2 . As previously mentioned, a leakage current of a MOSFET device under dormant mode may increase gradually as the device is aged and degraded, which eventually leads to leakage current runaway and causes catastrophic failure in the device and circuit. Normally, the leakage current increases by more than a factor of three (3V(t 0 )) before leakage current runaway occurs. The reference voltage may be effectively defined, for example, by a doubling (2V(t 0 )) in leakage current from its initial value at time t 0 . Therefore, the trigger for detecting leakage current runaway occurs when the product of the gain and the voltage difference due to leakage current for a time Δt is greater than the reference voltage Vref.
It should be noted that it is important that the reference voltage generator 30 provides a stable output voltage Vref which does not vary with temperature, process variations, and power supply voltage, and the like. According to a sample embodiment, a band-gap reference is used to provide a stable reference voltage that is insensitive to voltage and temperature. The band-gap reference is a voltage reference circuit widely used in circuit designs; it provides 1.25V output voltage, close to the theoretical 1.22 eV band-gap voltage of Silicon at 0K.
The output from the current shift monitor unit 20 AΔV is compared against the reference voltage Vref using the voltage comparator 40 . An alert or repair signal Vflag is generated when the product of the gain and the voltage difference from the differential amplifier 26 are greater than the reference voltage (i.e., AΔV>Vref), a critical point early in the detection of leakage current runaway when repair (i.e. leakage mitigation) is still possible. The alert signal Vlag is provided to the leakage current target unit 10 , causing the target semiconductor device 14 (i.e. MOSFET) 14 to be switched from dormant mode (Vgate=Vsource=0V, Vdrain=Vdd) to an active mode to allow for leakage current mitigation by applying Vfix from the repair voltage generator 50 to the gate of the target semiconductor 14 (Vgate=Vfix, Vdrain=Vdd, Vsource=0V).
FIG. 5 is an embodiment of a circuit diagram of the leakage current shift detection and mitigation circuit 100 shown previously in FIG. 2 with a single leakage current target semiconductor device 14 . The first switch control logic device 12 may be comprised of a network of switches, a network of transistors configured as switches, or any other device or network suitable for switching one of two or more input voltages to an output in response to one or more control signals. In the illustrated sample embodiment, the first switch control logic unit 12 controls three switches: SWon, SWoff and SWfix for biasing the target semiconductor device 14 in operating, dormant, and repairing modes (i.e. leakage mitigation), respectively. As an example for monitoring leakage current, switches SWon and SWfix are both open, while switch SWoff is closed.
As also shown in FIG. 5 , a second switch control logic device 22 in the current shift monitor unit 20 controls another four switches: SWen, SW 1 , SW 2 and SWcln for enabling the leakage current monitoring by charging and discharging charge collecting devices 241 and 242 shown as capacitors C 1 and C 2 , respectively, which as previously described also convert the collected current into corresponding voltages. As an example for monitoring leakage current shift from time t 1 to time t 2 , switch SWen is first closed and the leakage current I(LEAK) directed to the first capacitor C 1 to generate V 1 (t 1 ) by closing switch SW 1 while keeping both SW 2 and SWcln open for the first period of time between t 0 and t 1 . The leakage current I(LEAK) is then directed to the second capacitor C 2 to generate V 2 (t 2 ) by opening SW 1 and closing SW 2 for the next period of time from t 1 to t 2 . Both switches SW 1 and SW 2 are then opened for comparison of the voltages on the capacitors C 1 and C 2 by the differential amplifier 26 to produce the voltage AΔV, which completes the first leakage current comparison cycle. The comparator 40 receives the signal AΔV and a reference voltage Vref from the reference voltage generator 30 . The comparator generates a repair signal Vflag if the signal AΔV from the differential amplifier 26 is greater than the reference voltage Vref.
After the voltage AΔV is generated from the differential amplifier as a result of the comparison between V 1 (t 1 ) and V 2 (t 2 ), capacitor C 1 is discharged by opening switch SWen and closing switches SW 1 and SWcln. Leakage current within the next period of time Δt is again integrated by capacitor C 1 to generate V 1 (t 3 ). Note that, at this time, the polarity of the differential amplifier 26 is reversed by a polarity switch logic device 28 before comparing V 1 (t 3 ) from capacitor C 1 with V 2 (t 2 ) from capacitor C 2 in the differential amplifier 26 to generate a new voltage signal AΔV, which completes the second leakage current comparison cycle.
When target semiconductor device repairing (i.e. leakage mitigation) is triggered by the comparator 40 , switch SWen is first opened by the second switch control logic device 22 to disable the current leakage monitoring process. In the presence of the repair signal Vflag, switch SWfix is closed via the first switch control logic device 12 while both switches SWoff and SWon are opened to bias the target semiconductor device 14 under repairing mode; this has the effect of switching the target semiconductor device 14 from a dormant to an active state.
FIG. 6 is a block diagram of another embodiment of a circuit 200 for detecting and mitigating leakage current shift within a plurality of leakage current target semiconductor units 10 , individually designated as 10 A, 10 B, 10 C, 10 D, etc. Only one leakage current target unit is selected at a time, on which to perform leakage current monitoring and mitigation; such selection and repair is conducted via a multiplexer (MUX) unit 16 controlled by a target selection logic device 18 . This arrangement effectively saves chip area when more than one leakage current target unit is present. Each leakage current target unit 10 A, 10 B, 10 C, 10 D, etc. consists of a switch control logic device and target semiconductor device as shown in FIG. 3 . The current shift monitor unit 20 , reference voltage generator 30 , comparator 40 , and repair voltage generator 50 are essentially the same as is illustrated in FIG. 2 and described previously.
The total testing period (Δt(total)) for a plurality of leakage current target units 10 is the sum of the test time for each individual unit 10 A, 10 B, 10 C, 10 D, etc., where each leakage current target unit is tested for consecutive temporal periods Δt. Thus, Δt(total) should be short enough to identify and mitigate any single leakage current runaway event (e.g. not more than a few tens of a second in one embodiment of invention). A leakage current shift that is not mitigated in this time may cause permanent damage to a target semiconductor device. Consequently, the individual testing time Δt of each target semiconductor device should be adjusted (or minimized) accordingly in order to accommodate the plurality of leakage current target units 10 .
The preceding description and accompanying drawings are intended to be illustrative and not limiting of the invention. The scope of the invention is intended to encompass equivalent variations and configurations to the full extent of the following claims. | A dormant mode target semiconductor device within a leakage current target unit is identified for mitigating leakage current to prevent it from reaching catastrophic runaway. A leakage current shift monitor unit is electrically connected to the output node of the leakage current target unit and collects leakage current from the selected target semiconductor device for two consecutive predefined temporal periods and measures the difference between the collected leakage currents. A comparator receives and compares the outputs of the current shift monitor unit and a reference voltage generator. The comparator propagates an alert signal to the leakage current target unit when the leakage voltage output from the leakage current shift monitor unit exceeds the reference voltage, a condition that indicates that the leakage current is about to approach catastrophic runaway levels. This alert signal switches the target semiconductor device to an active mode for leakage mitigation, which includes a repair voltage from a repair voltage generator applied to the gate of the target semiconductor device. | 7 |
SUMMARY OF THE INVENTION
This invention relates to a yarn-piecing system for a freed-fiber spinning device.
The yarn-piecing system comprises an automaton whose main function is to piece together threads which have been accidentally broken during formation. This automaton moves continuously along a rail in front of the spinning units. When the yarn delivery is interrupted within one of these units, a device for checking the presence of the yarn gives the automaton the order to stop in front of said spinning unit and to carry out piecing of the yarn. The yarn-piecing operation is performed by bringing back the length of yarn which emerges from the nozzle of the corresponding spinning unit and by producing a partial vacuum within this latter in order to withdraw the end of said length of yarn by suction during operation of the unit. The end of the yarn thus introduced is mixed with the fibers as they are projected into the collecting duct of the rotor, is re-discharged from the machine and wound onto the bobbin, thus drawing with it the newly formed yarn.
At the time of an interruption of the fiber supply (when the feed can is empty, for example), the yarn-piecing automaton carries out its operation without success and accordingly remains stationary in front of a spinning unit which is out of service. Should it prove necessary to perform yarn-piecing operations on other units during this stationary period, they cannot be carried out by the automaton, thus producing a stoppage of said units and causing a drop in production of the spinning machine.
The aim of the invention is to overcome this disadvantage by cancelling the automaton-stopping order produced by interruption of the yarn delivery by superimposing thereon an order for continuation of travel of the automaton emanating from the absence of a fiber sliver within the feed duct. At the same time, this second order triggers an alarm for providing supervisory personnel with a warning to the effect that a servicing operation is urgently required.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will be more apparent upon consideration of the following description and accompanying drawings in which one embodiment of the invention is illustrated by way of example and not in any limiting sense, and in which:
FIG. 1 is a highly diagrammatic view of a spinning unit, a yarn-piecing automaton being stopped in front of said unit and a device in accordance with the invention being installed on said automaton;
FIG. 2 is a view in perspective showing the duct for feeding fibers to the spinning unit.
DETAILED DESCRIPTION
The freed-fiber spinning unit 1 is supplied with a fiber sliver 2 which passes out of a feed can 3. The yarn 4 thus produced passes in front of a yarn breakage checking device 5 of known type before being taken up by the rollers 6. For a variety of reasons, it can happen that the yarn 4 breaks. In the event of such an occurrence, the checking device 5 (consisting of a switch, for example) closes and transmits a signal to an automaton 7 which accordingly stops in front of the spinning unit 1 for the purpose of piecing the yarn in accordance with a well-known mode of operation described in particular in U.S. Pat. No. 4,159,620 issued July 3, 1979. When the device 5 no longer detects the presence of the yarn 4, this absence of yarn may arise from faulty supply of the sliver 2.
From that time onwards, although the movement of the contact of the device 5 to the closed position has had the effect of transmitting an order to the automaton 7, the yarn-piecing operation cannot be performed by the automaton which therefore remains stationary in front of the spinning unit concerned as long as this latter is not supplied again with sliver. Accordingly, it becomes readily apparent that this immobilization of the automaton is liable to have an adverse effect on productivity by reason of the fact that, as long as the automaton does not receive any order to resume its travel, it cannot move to another spinning unit in which it may prove necessary to carry out a yarn-piecing and/or cleaning operation.
In order to overcome this drawback and in accordance with a first embodiment of the invention, the wall 8 of the duct 9 for supplying slivers 2 is formed of reflecting material such as a polished metal or metallized plastic material. When the duct wall is no longer covered by the sliver 2, the light emitted by a light source 10 mounted for example on the frame of the machine can accordingly be reflected from said duct wall to a photoelectric cell 11 mounted on the automaton 7. By means of an electric or electronic device of known type, the photoelectric cell transmits to the automaton 7 the order not to stop in front of the spinning unit 1. At the same time, the photoelectric cell triggers an alarm system 12 which is intended to warn supervisory personnel of the need to perform a servicing operation.
This alarm may be mounted at any suitable location of the spinning installation (on the spinning unit 1, for example) and can consist of a light or sound signal or a combination of both, the sound signal being intended to attract the operator's attention and the light signal being intended to permit rapid identification of the unit which is out of service.
In accordance with a second embodiment of the invention (not shown in the drawings), the sliver of fibers 2 passes in front of a proximity detector which is attached to one of the walls of the fiber feed duct. When delivery of fibers is interrupted, the distance between the proximity detector and the opposite wall of the feed duct is modified, thereby producing a signal which initiates displacement of the automaton and actuation of the alarm. This system does not make it necessary to provide the fiber feed duct with a special wall as was the case in the previous embodiment.
In accordance with a third embodiment of the invention (also omitted from the drawings), use is made of an electric microswitch which is fixed in such a manner as to ensure that the fiber sliver is applied against its control lever. When the fiber sliver is interrupted, the lever is accordingly released and initiates closing of the contact which is opened by the yarn checking device. Thus the automaton continues its travel instead of stopping in front of a spinning unit in which no yarn is present by reason of a failure of supply of fiber sliver and the alarm system is triggered.
One solution which proves particularly advantageous since the yarn-piecing automaton is associated with a device for delivering compressed air lies in the use of a pneumatic contact. The fiber sliver compresses the blade-spring which is released when the supply of fibers is interrupted. A valve then operates a micro-jack which in turn closes the electrical contact opened as a result of a yarn shortage and triggers the alarm.
The design solutions mentioned in the foregoing have been given solely by way of example and not in any limiting sense. Any device which is capable of cancelling the order transmitted to the automaton by the yarn shortage detector and of triggering the alarm system is included within the scope of the invention. | An order produced by an interruption of yarn delivery at the exit of a spinning unit is cancelled so that the yarn-piecing automaton does not stop in front of the unit but continues to travel towards another spinning unit. At the same time, an alarm system is automatically triggered in order to warn operating personnel that a servicing operation is urgently required. | 3 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to cameras and photography systems, and more particularly, to a system for photographing an event simultaneously using multiple cameras.
BACKGROUND OF THE INVENTION
[0002] Statement of the Problem
[0003] It is a problem to photograph a single event from multiple angles simultaneously using a plurality of cameras. Previously, an event could be photographed by a single camera using multiple slave flash triggers, each of which is connected to a separate flash unit. However, there was, heretofore, no simple method for synchronizing a plurality of cameras to essentially simultaneously photograph a single event from multiple perspectives, angles, or locations.
[0004] Solution to the Problem
[0005] The present system solves the above problem and achieves an advance in the field by synchronizing the capture of an image of a target subject by a master camera with the capture of an image of the subject by one or more slave cameras, each of which is located at a different position relative to the subject to be photographed.
[0006] Initially, a light pulse is transmitted by a ‘master’ camera when the camera's shutter button is pressed. Image capture (exposure) synchronization of the slave cameras is accomplished via an optical sensing system on each slave camera that detects a light pulse (e.g., a flash or strobe) transmitted from the master camera which causes the slave camera's electronic ‘shutter’ to trigger and record an image present on the camera's CCD (the ‘charge-coupled device’ that detects the image) if the detected light pulse is within certain parameters. These parameters may be manually selected for each camera to establish an appropriate image capture mode for a particular situation. An image may thus be captured from each of the different angles, relative to the subject being photographed, at which the cameras are positioned.
[0007] Any one of several image capture modes may be selected by a user of the present system. These modes include the detection of light pulses in the infrared, ultraviolet, and visible spectrum, as well as light pulses having a predetermined strobe pulse sequence or other characteristics. Slave cameras may also be triggered by light pulses emitted from other cameras (such as conventional film cameras) or flash units that emit any basic type of flash or strobe.
[0008] The slave mode camera system disclosed herein is useful for capturing sporting events as well as social events such as birthday parties, weddings, and the like. The system may also be used for security monitoring and photographic recording of any event of potential interest, where it is advantageous to capture the event from multiple camera angles. In addition, the use of multiple camera angles can provide useful information in applications such as failure analysis of structures and in other types of testing environments.
[0009] The present system also takes advantage of technology available in many existing digital cameras, requiring only the addition of software or firmware that functions in accordance with the method described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [0010]FIG. 1A illustrates components of interest in a digital camera programmed in accordance with the present system;
[0011] [0011]FIG. 1B illustrates, in further detail, certain aspects of processor 110 ;
[0012] [0012]FIG. 2 is a diagram showing an exemplary arrangement of a master camera and two slave cameras;
[0013] [0013]FIG. 3 is a flowchart illustrating an exemplary set of steps performed by a slave camera in effecting the present system;
[0014] [0014]FIG. 4 is a flowchart illustrating an exemplary set of steps performed by a master camera; and
[0015] [0015]FIG. 5 is a diagram showing the timing relationships between strobes and image capture in a multiple camera scenario.
DETAILED DESCRIPTION
[0016] [0016]FIG. 1A illustrates components of interest in a digital camera 101 programmed in accordance with the present system. As shown in FIG. 1, camera 101 comprises one or more light receiving devices including light sensor 105 , infrared serial port transceiver 106 , and CCD 107 , which is the charge-coupled device that detects the image to be photographed. Camera 101 further comprises one or more light transmitting devices including light emitter 104 and infrared serial port transceiver 106 . Each of the light receiving devices 105 / 106 / 107 and each of the light transmitting devices 104 / 106 is coupled to processor 110 . Processor 110 is also coupled to shutter button 103 and image capture mode switch 102 , the function of which is described in detail below. Although three light receiving devices 105 / 106 / 107 and two light transmitting devices 104 / 106 are shown in FIG. 1, the present system is operable with any one of the light receiving devices and any one of the light receiving devices shown therein. Note that the term ‘exposure’ is used herein to denote the process of image capture by a digital camera, notwithstanding the fact that a digital camera does not use photographic film.
[0017] [0017]FIG. 1B illustrates, in further detail, certain aspects of an exemplary processor 110 . As shown in FIG. 1B, processor 110 provides a mode control function 111 ( 1 ) and a timer 114 . I/O interface block 120 in FIG. 1B includes a light input filter/decoder 112 and light output device driver 113 . Block 120 is shown in dotted lines as the I/O interface may be physically integrated with processor 110 , or functions provided by the interface may be performed by the processor in lieu of separate hardware devices. The functions provided by mode control unit 111 ( 1 ), filter/decoder 112 , driver 113 , and timer 114 (as explained below) may be optionally implemented by software, firmware, or hardware. In any event, the functions performed by blocks 110 and 120 are initiated in response to commands from processor 110 . Light receiving devices 105 / 106 / 107 are represented generically by light input (or optical input) device 108 , since only one of the devices 105 / 106 / 107 is required for operation of the present system. Light emitting devices 104 and 106 are likewise represented generically by light output device 109 , as only one of the devices 104 / 106 is required for system operation.
[0018] In an exemplary embodiment of the present system, light output device 109 is a typical camera strobe light, and light input device 108 is the camera's CCD 107 , since this device detects the wavelength of light emitted by a typical camera strobe. In an alternative embodiment, light input device 108 may be an infrared light sensor 105 which responds to infrared light emitted by an infrared light output device 104 such as an IR transistor, an IR diode, an IRDA module, or the like.
[0019] The present system typically operates with a normal camera flash unit (strobe light) functioning as light emitter 104 . The type of strobe (light pulse) emitted by a normal flash unit typically has a pulse duration between approximately 250 microseconds and 4 milliseconds, and comprises light in the visible spectrum between approximately 450 and 700 nanometers. In an alternative embodiment, the strobe may emit light in the infrared or ultraviolet spectral region. The present system may be programmed via image capture mode switch (or other input device) 102 for operation with many possible strobe types, as well as programmed to ignore potentially false trigger pulses such as pre-flashes used for red-eye reduction and exposure testing. In addition, a slave camera 101 may be set to a mode wherein it triggers the capture of an image (i.e., an exposure) only in response to receiving a light pulse from another camera having a specific strobe characteristic such as a predefined strobe pulse sequence and/or a specific wavelength. Other types of strobes 104 might include infrared (IR), and ultraviolet (UV) for specialized photography.
[0020] [0020]FIG. 2 is a diagram showing an exemplary arrangement of a master camera and two slave cameras in accordance with the present system. As shown in FIG. 2, master camera 101 ( 1 ) and one or more slave cameras 101 ( 2 ) and 101 ( 3 ) are positioned so that all of the cameras are pointed at a target subject 201 . Each of the cameras is positioned at a different location to provide a corresponding different viewing angle of the target subject 201 .
[0021] [0021]FIG. 5 is a diagram showing the timing relationships between strobes and image capture in a multiple camera scenario. Operation of the present system is best understood by viewing FIG. 2 and FIG. 5 in conjunction with one another.
[0022] In operation, when shutter button 103 on master camera 101 ( 1 ) is pressed (at reference number/mark 500 in FIG. 5), the camera 101 ( 1 ) starts the exposure (image capture) Exp. 1 of the target subject 201 , and the camera's light output device 109 emits a light pulse 205 (FIG. 2) which is detected (at mark 501 ) by a light input device 108 on each slave camera 101 ( 2 ) and 101 ( 3 ). Slave camera 101 ( 2 ) then starts a timer 114 with a delay t 1 (Delay 1 ) sufficient to avoid ‘seeing’ the light pulse (strobe) 205 from master camera, e.g., 10 milliseconds. Delay t 1 is at least equal to, or preferably, slightly greater than (by approximately 15 to 25 percent) the length of time it takes for a typical light pulse 205 to decay to a level of zero or near-zero luminosity where it will not adversely affect the exposure of the slave camera. When the timer has expired (at mark 502 ), slave camera 101 ( 2 ) triggers its strobe 206 and starts the exposure Exp. 2 of the target subject 201 . When light pulse 205 is detected (at mark 501 ) by slave camera 101 ( 3 ), it starts a timer 114 with a delay equal to t 1 +t 1 (2×t 1 ), since this camera 101 ( 3 ) must wait until the light pulse 206 from the strobe of slave camera 101 ( 2 ) has decayed. In the general case, the nth slave camera in a given system will have a timer delay of n×t, where t is a value slightly greater than the duration of the light pulse being employed.
[0023] Slave camera 101 ( 3 ) ignores strobe 206 from camera 101 ( 2 ), and at mark 503 , the timer for slave camera 101 ( 3 ) expires, and camera 101 ( 3 ) then triggers its strobe 207 and starts the exposure (Exp. 3 ) of the target subject 201 . An image of target subject 201 is thus captured in near simultaneity from each of the different angles, relative to the subject, at which the cameras 101 ( 1 )- 101 ( 3 ) are positioned.
[0024] [0024]FIG. 3 is a flowchart illustrating an exemplary set of steps performed by a slave camera in carrying out a method in accordance with the present system. As shown in FIG. 3, at step 305 , a user sets the image capture mode for master camera 101 ( 1 ) using mode switch 102 . At step 305 , the image capture mode setting is input to mode control software or firmware to establish a number of manually selected parameters for a given camera for a particular situation. Any one, or a combination of these parameters may be selected to cause a camera 101 to initiate an exposure only when a received light pulse has characteristics that correspond with each of the parameters associated with a selected image capture mode. These parameters include:
[0025] (a) the master or slave status of the camera;
[0026] (b) for slave cameras, the slave's ‘firing’ order, i.e., whether this particular slave is the second, third, etc., camera to trigger a strobe/exposure;
[0027] (c) the light output device 108 to be triggered;
[0028] (d) the light input device 109 (if camera is a slave, or in the case of a master camera, where the camera is to be triggered remotely)
[0029] (e) the strobe pulse coding sequence (if a predefined strobe pulse sequence is one of the parameters for a specific mode);
[0030] (f) a specific wavelength range (if light pulses having a particular type of spectral characteristic are to be ignored); and
[0031] (g) whether image capture by a camera in master camera mode is to be triggered by shutter button 103 or by an external strobe.
[0032] The above parameters are pre-established in mode control unit 111 ( 1 ) via software, firmware, or hardware, prior to use of camera 101 . The image capture mode settings selected at a given time on each camera in the present system must correspond to one another; i.e., a corresponding slave camera must have a light input device 108 that is capable of detecting the wavelength and coding sequence, if any, of the strobe emitted by the master camera.
[0033] For a given image capture mode, light output driver 113 may be used to implement a predefined strobe pulse coding sequence for a master or slave camera, and also to select the appropriate light output device. Filter/decoder 112 may be used, correspondingly, to detect a predefined strobe pulse coding sequence for a slave camera. IRDA serial port transceiver 106 may be used to facilitate the light pulse coding and communication between a master camera and one or more slave cameras. Filter/decoder 112 may also be used to signal processor 110 that an appropriate strobe has been detected by filtering out a predetermined range of wavelengths in accordance with a particular image capture mode to avoid unwanted triggering of a camera due to receiving strobes or light pulses from extraneous sources.
[0034] Mode (f), above, may be implemented whereby a slave camera fires when any other basic type of strobe is detected. Therefore, a conventional film camera with a typical flash unit can be employed as a master camera in the present system.
[0035] At step 310 , a user sets the image capture mode for a slave camera ( 101 ( 2 ), for example) using mode switch 102 . The image capture mode setting is then input to mode control software or firmware 111 ( 1 ) to establish the appropriate parameters, for the selected mode, for timer 114 , filter/decoder 112 , and light output driver 113 . At step 315 , master camera 101 ( 1 ) starts the exposure and triggers the light pulse in accordance with the selected mode.
[0036] All remaining steps in FIG. 3 are performed by each of the slave cameras. At step 320 , the slave camera firmware 111 monitors the input from light input device 108 , as filtered and decoded by filter/decoder 112 (if filtering and/or decoding is necessary in accordance with the selected mode parameters). At step 325 , a light pulse reaches the camera, and at step 330 , firmware 111 determines whether the received pulse is within the parameters established for the selected mode, assuming that filter/decoder 112 has sent a signal, indicative of the type of light pulse, to firmware 111 in processor 110 . If no such signal is generated by filter/decoder 112 , or if firmware 111 determines that the signal received from filter 112 does not fall within the present image capture mode parameters, then the received light pulse is ignored, at step 335 , and monitoring continues at step 320 .
[0037] At step 340 , delay timer 114 is started, as described above with respect to FIG. 5. Finally, at step 350 , when timer 114 times out, an exposure and a strobe are initiated by the slave camera.
[0038] [0038]FIG. 4 is a flowchart illustrating an exemplary set of steps performed by a master camera 110 ( 1 ). As shown in FIG. 4, at step 405 , the image capture mode is selected by a user. At step 410 , the mode setting is then input to mode control software or firmware 111 ( 1 ) to establish the appropriate parameters, for the selected mode, for filter/decoder 112 and light output driver 113 . At step 415 , if the selected mode indicates that an exposure is to be triggered by an external strobe instead of shutter button 103 , then firmware 111 waits either for the strobe to be received at step 420 , or for the shutter button to be pressed at step 425 . Upon the detection of either the shutter button being pressed, or receipt of an external strobe (according to the selected mode), at step 430 , an exposure is initiated and the selected type of strobe is triggered via light output device driver 113 and the appropriate light output device 109 .
[0039] It should be noted that the present system is operational with any number of slave cameras, and furthermore, that there is not necessarily any functional distinction between a camera used as a master camera and a camera used as a slave camera, other than the image capture mode in which a given camera may be operating at a specific time.
[0040] While exemplary embodiments of the present invention have been shown in the drawings and described above, it will be apparent to one skilled in the art that various embodiments of the present invention are possible. For example, the specific sequence of steps described above in FIGS. 3 and 4, as well as the particular configuration of components shown in FIGS. 1A and 1B, should not be construed as limited to the specific embodiments described herein. Modification may be made to these and other specific elements of the invention without departing from its spirit and scope as expressed in the following claims. | A system for synchronizing the exposure of an image by a master camera with the exposure of an image by one or more slave cameras, each of which is located at a different position relative to a common subject to be photographed. Exposure synchronization is accomplished via an optical sensing system on each slave camera that detects a light pulse (e.g., a flash or strobe) from the master camera emitted simultaneously with the initiation of the exposure of the subject, causing the slave camera to trigger an exposure of the subject, if the detected light pulse is within the parameters of the image capture mode manually selected for a given camera. An image may thus be captured from each of the different angles, relative to the subject being photographed, at which the cameras are positioned. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a Continuation Application of PCT Application No. PCT/JP2004/003785, filed Mar. 19, 2004, which was published under PCT Article 21 (2) in English.
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-383925, filed Nov. 13, 2003, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a nonvolatile semiconductor memory device capable of storing, for example, two bits or more of data.
2. Description of the Related Art
A nonvolatile semiconductor memory device capable of storing multivalued data, such as a NAND flash memory using EEPROM, has been proposed (for example, refer to Jpn. Pat. Appln. KOKAI Publication No. 2000-195280).
In a NAND flash memory, all of or half of a plurality of cells arranged in the row direction are written into or read from simultaneously. The NAND cells constituting each NAND flash memory are connected via bit lines to a write and read latch circuit.
In a NAND flash memory which stores multivalued data, a threshold voltage according to the writing data is set in a memory cell, which enables a plurality of bits of data to be stored in the memory cell. To suppress the threshold voltage distribution, writing is done at a threshold voltage lower than the original threshold voltage in a first write operation. Then, in a second write operation, writing is done to the original threshold voltage. When data is written by this method, the writing data is not left in the data storage circuit after the first write operation. For this reason, after the first write operation, the writing data is read out in a read operation and then determined. However, the data written in the first write operation cannot be read accurately because it is lower than the original threshold voltage. To overcome this problem, it is necessary to store three bits of data, including the first writing data, the second writing data, and the data written in a lower page (a page preceding the page now being written into). A storage circuit for storing those data items is composed of, for example, two CMOS latch circuits and a precharge transistor for holding the data read from the memory cell in verifying the data bit by bit and forcing the data to be set to data “1”. As a result, the storage circuit has the demerit of occupying a larger area. Therefore, there has been a need for a nonvolatile semiconductor memory device which is capable of eliminating a storage circuit for storing the data necessary for writing and of writing multivalued data with a simpler circuit configuration.
BRIEF SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a nonvolatile semiconductor memory device comprising: a memory cell which stores a plurality of data items in n-valued (n is a natural number equal to one or more) threshold voltages; a first data storage circuit which is connected to the memory cell and which stores externally inputted data of a first logic level or a second logic level; a second data storage circuit which is connected to the memory cell and which stores the data of the first logic level or second logic level read from the memory cell; and a control circuit which controls the memory cell and the first and second data storage circuits and which manipulates the data stored in the first and second data storage circuits in the middle of writing data into the memory cell, reproduces the externally inputted data, and resumes writing data into the memory cell.
According to a second aspect of the present invention, there is provided a nonvolatile semiconductor memory device comprising: a memory cell which stores a plurality of data items in n-valued (n is a natural number equal to one or more) threshold voltages; a first data storage circuit which is connected to the memory cell and which stores externally inputted data of a first logic level or a second logic level; a second data storage circuit which is connected to the memory cell and which stores the data of the first logic level or second logic level read from the memory cell; and a control circuit which controls the memory cell and the first and second data storage circuits and which sets the logic level of the data stored in the second data storage circuit to the first logic level when the logic level of the externally inputted data is the second logic level, carries out a write operation of raising the threshold voltage of the memory cell when the logic level of the data stored in the first data storage circuit is the first logic level, sets the logic level of the data stored in the first data storage circuit to the second logic level when the memory cell has reached the first threshold voltage, holds the threshold voltage of the memory cell without changing the threshold voltage when the logic level of the data stored in the first data storage circuit is the second logic level, and continues writing until the logic level of the first data storage circuit has reached the second logic level, sets the logic level of the data stored in the first data storage circuit to the first logic level when the logic level of the data stored in the second data storage circuit is the second logic level, and carries out a write operation of raising the threshold voltage of the memory cell when the logic level of the data stored in the first data storage circuit is the first logic level, sets the data stored in the first data storage circuit to the second logic level when the memory cell has reached the second threshold voltage, and holds the threshold voltage of the memory cell without changing the threshold voltage when the logic level of the data stored in the first data storage circuit is the second logic level.
According to a third aspect of the present invention, there is provided a nonvolatile semiconductor memory device comprising: a memory cell which stores a plurality of data items in n-valued (n is a natural number equal to one or more); and a write circuit which writes data into the memory cell and which writes k-valued data at a threshold voltage a little lower than the original threshold voltage into the memory cell in a write operation of writing an i-th data item into the memory cell, writes (k+1)-valued or more-valued data into the memory cell in a j-th write operation, and sets the threshold voltage of the k-valued data before the j-th write operation.
According to a fourth aspect of the present invention, there is provided a nonvolatile semiconductor memory device comprising: a memory cell which stores a plurality of data items in n-valued (n is a natural number equal to one or more) threshold voltages; a first data storage circuit which is connected to the memory cell and which stores externally inputted data of a first logic level or a second logic level; a second data storage circuit which stores the data of the first logic level or second logic level read from the memory cell; and a control circuit which controls the memory cell and the first and second data storage circuits and which, when writing the largest one of the data items to be written into the memory cell, writes the largest data item to the original threshold voltage in one write operation and writes the data items other than the largest one in a plurality of write operations.
According to a fifth aspect of the present invention, there is provided a nonvolatile semiconductor memory device comprising: a memory cell which stores n bits (n is a natural number equal to one or more) of data with a plurality of threshold voltages; a first data storage circuit which is connected to the memory cell and which stores externally inputted data of a first logic level or a second logic level; a second data storage circuit which stores the data of the first logic level or second logic level read from the memory cell; and a control circuit which controls the memory cell and the first and second data storage circuits and which writes data into the memory cell bit by bit in the n bits and raises the threshold voltage of the memory cell by writing the data in each bit in still another plurality of write operations.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a circuit diagram of a data storage circuit according to a first embodiment of the present invention;
FIG. 2 is a schematic block diagram of a nonvolatile semiconductor memory device according to the present invention;
FIG. 3 is a circuit diagram showing the configuration of the memory cell array and bit-line control circuit shown in FIG. 2 ;
FIGS. 4A and 4B are sectional views of a memory cell and a select transistor, respectively;
FIG. 5 is a sectional view of a NAND cell;
FIGS. 6A , 6 B, and 6 C show the relationship between the data in a memory cell and the threshold voltage of the memory cell;
FIGS. 7A and 7B show the relationship between the data in a memory cell and the threshold voltage of the memory cell;
FIG. 8 is a flowchart showing a first page write operation;
FIG. 9 is a flowchart showing a second page write operation;
FIGS. 10A and 10B show the relationship between each data cache and the data in the memory cell in the first page write operation;
FIG. 11 shows the relationship between each data cache and the data in the memory cell in the first page write operation;
FIGS. 12A and 12B show the relationship between each data cache and the data in the memory cell in the second page write operation;
FIGS. 13A and 13B show the relationship between each data cache and the data in the memory cell in the second page write operation;
FIG. 14A shows data stored in the data cache after the second page read operation and FIG. 14B shows data stored in the data cache after the first page read operation;
FIG. 15 , which shows a second embodiment of the present invention, is a flowchart showing a second page program operation;
FIG. 16 shows a configuration of a memory cell array and a data storage circuit applied to a third embodiment of the present invention;
FIGS. 17A , 17 B, and 17 C show the relationship between the data in a memory cell and the threshold voltage of the memory cell according to the third embodiment;
FIGS. 18A and 18B show the relationship between the data in a memory cell and the threshold voltage of the memory cell according to the third embodiment;
FIG. 19 , which is related to the third embodiment, shows the order of writing data into a memory cell;
FIG. 20 , which is related to the third embodiment, is a flowchart showing a case where data is written into cells adjacent to the second page after the date in the second page is written;
FIG. 21 is a flowchart showing a third page write operation related to the third embodiment;
FIGS. 22A and 22B show the data stored in the data cache as a result of the third page write operation of FIG. 21 ;
FIGS. 23A and 23B show the data stored in the data cache as a result of the third page write operation of FIG. 21 ; and
FIG. 24 is a circuit diagram of a data storage circuit according to a fifth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, referring to the accompanying drawings, embodiments of the present invention will be explained.
First Embodiment
FIG. 2 schematically shows the configuration of a nonvolatile semiconductor memory device according to the present invention. For example, the configuration of a NAND flash memory which stores 4-valued (2 bits of) data is shown in FIG. 2 .
A memory cell array 1 includes a plurality of bit lines, a plurality of word lines, and a common source line. In the memory array 1 , for example, memory cells are arranged in a matrix. Each of the memory cells is composed of an EEPROM cell and enables data to be rewritten electrically. A bit control circuit 2 for controlling bit lines and a word line control circuit 6 are connected to the memory cell array 1 .
The bit line control circuit 2 includes a plurality of data storage circuits as described later. The bit line control circuit 2 reads the data in a memory cell in the memory cell array 1 via a bit line, detects the state of a memory cell in the memory cell array 1 via a bit line, or writes data into a memory cell in the memory cell array 1 by applying a write control voltage to the memory cell via a bit line. A column decoder 3 and a data input/output buffer 4 are connected to the bit line control circuit 2 . The data storage circuits in the bit line control circuit 2 are selected by the column decoder 3 . The data in a memory cell read into a data storage circuit is outputted via the data input/output buffer 4 from a data input/output terminal 5 to the outside world.
Writing data externally inputted to the data input/output terminal 5 is inputted via the data input/output buffer 4 to the data storage circuit selected by the column decoder 3 .
The word line control circuit 6 is connected to the memory cell array 1 . The word line control circuit 6 selects a word line in the memory cell array 1 and applies a voltage necessary for reading, writing, or erasing to the selected word line.
The memory cell array 1 , bit line control circuit 2 , column decoder 3 , data input/output buffer 4 , and word line control circuit 6 , which are connected to a control signal and control voltage generating circuit 7 , are controlled by the control signal and control voltage generating circuit 7 . The control signal and control voltage generating circuit 7 , which is connected to a control signal input terminal 8 , is controlled by a control signal externally inputted via the control signal input terminal 8 .
The bit line control circuit 2 , column decoder 3 , word line control circuit 6 , and control signal and control voltage generating circuit 7 constitute a write circuit and a read circuit.
FIG. 3 shows the configuration of the memory cell array 1 and bit line control circuit 2 of FIG. 2 . In the memory cell array 1 , a plurality of NAND cells are provided. A NAND cell is composed of memory cells MCs (made up of, e.g., 16 EEPROMs) connected in series and a first and a second select gate S 1 , S 2 . The first select gate S 1 is connected to bit line BL 0 and the second select gate S 2 is connected to source line SRC. The control gates of the memory cells arranged in each row are connected equally to word lines WL 1 , WL 2 , WL 3 , . . . , WL 16 . First select gates S 1 are connected equally to select line SG 1 and second select gates S 2 are connected to select line SG 2 .
The memory cell array 1 includes a plurality of blocks as shown by the broken lines. Each block is composed of a plurality of NAND cells. The data is erased in blocks. An erase operation is performed simultaneously on the two bit lines connected the data storage circuit 10 .
A plurality of memory cells (the memory cells enclosed by the broken line) provided every other bit line and connected to a single word line constitute a sector. Data is written or read in sectors. In a sector, for example, two pages of data are stored.
In a read operation, a program verify operation, and a program operation, one bit line is selected from the two bit lines (BLi, BLi+1) connected to the data storage circuit 10 according to the address signal (YA 1 , YA 2 , . . . , YAi, YA 4023 ) externally specified. In addition, according to an external address, one word line is selected and one sector (for two pages) is selected. The switching between the two pages is effected according to the address.
FIGS. 4A and 4B are sectional views of a memory cell and a select transistor, respectively. FIG. 4A shows a memory cell. In a substrate 41 , an n-type diffused layer 42 acting as the source and drain of a memory cell is formed. Above the substrate 41 , a floating gate (FG) 44 is formed via a gate insulating film 43 . Above the floating gate 44 , a control gate (CG) 46 is formed via an insulating film 45 . FIG. 4B shows a select gate. In the substrate 41 , an n-type diffused layer 47 acting as a source and a drain is formed. Above the substrate 41 , a control gate 49 is formed via a gate insulating film 48 .
FIG. 5 is a sectional view of a NAND cell in the memory cell array. In this example, in the NAND cell, 16 memory cells MCs configured as shown in FIG. 4A are connected in series. The drain side and source side of the NAND cell are provided with a first select gate S 1 and a second select gate S 2 configured as shown in FIG. 4B , respectively.
FIG. 1 is a circuit diagram of the data storage circuit 10 shown in FIG. 3 .
The data storage circuit 10 has a primary data cache (PDC), a dynamic data cache (DDC), a temporary data cache (TDC). The PDC and DDC hold the input data in a write operation, hold the read data in a read operation, hold the data temporarily in a verify operation, and are used to manipulate the internal data in storing multivalued data. The TDC not only amplifies the data on the bit line in reading the data and holds the data temporarily, but also is used to manipulate the internal data in storing multivalued data.
The PDC is composed of clocked inverter circuits 61 i, 61 j and a transistor 61 k. The transistor 61 k is connected between the input terminal of the clocked inverter circuit 61 i and the input terminal of the clocked inverter circuit 61 j . A signal EQ 1 is supplied to the gate of the transistor. The nodes N 1 a, N 1 b serving as the input terminals of the clocked inverter circuits 61 i , 61 j are connected via column select transistors 61 a, 61 b to output data lines IO, IOn, respectively. A column select signal CSLi is supplied to the gates of the transistors 61 a, 61 b.
Furthermore, the node N 1 b of the PDC is connected to the gate of a transistor 61 l. A signal COMi is supplied to one end of the current path of the transistor 61 l. The other end of the current path of the transistor 61 l is connected via a transistor 61 m to the ground. In addition, the other end of the current path of the transistor 61 l is connected via a transistor 61 g and a transistor 61 d to the ground. A signal CHK 1 is supplied to the gate of the transistor 61 m. The gate of the transistor 61 g is connected to a node N 3 described later. A signal CHK 2 is supplied to the gate of the transistor 61 d.
The signal COMi, which is common to all of the data storage circuits 10 , indicates whether all of the data storage circuits 10 have been verified. Specifically, as described later, if the verify operation has been completed, the nodes N 1 a of the PDCs of all of the data storage circuits 10 go high. In this state, when the signals CHK 1 and CHK 2 are made high, if the verify operation has been completed, the signal COMi goes high.
Between the output terminal of the inverter circuit 61 i and the ground, a transistor 61 c is connected. A preset signal PRST is supplied to the gate of the transistor 61 c. The transistor 61 c, which operates according to the preset signal PRST, sets the node N 1 b of the PDC at VSS (low level). That is, the node N 1 a of the PDC is set at Vdd (high level).
The TDC is composed of, for example, a MOS capacitor 61 p. The capacitor 61 p is connected between the junction node N 3 of transistors 61 g, 61 h and the ground. The DDC is connected via transistors 61 q, 61 h to the junction node N 3 . A signal REG is supplied to the gate of the transistor 61 q. A signal BLC 1 is supplied to the gate of the transistor 61 h.
The DDC is composed of transistors 61 r, 61 s. A signal VREG is supplied to one end of the current path of the transistor 61 r. The other end of the transistor 61 r is connected to the current path of the transistor 61 q. The gate of the transistor 61 r is connected via the transistor 61 s to the node N 1 a of the PDC. A signal DTG is supplied to the gate of the transistor 61 s.
Furthermore, one end of the current path of transistors 61 t, 61 u is connected to the junction node N 3 . A signal VPRE is supplied to the other end of the current path of the transistor 61 u. A signal BLPRE is supplied to the gate of the transistor 61 t. A signal BLCLAMP is supplied to the gate of the transistor 61 t . The other end of the current path of the transistor 61 t is connected via a transistor 61 v to one end of bit line BLo and via a transistor 61 w to one end of bit line BLe. The other end of the bit line BLo is connected to one end of the current path of a transistor 61 x. A signal BlASo is supplied to the gate of the transistor 61 x. The other end of the bit line BLe is connected to one end of the current path of a transistor 61 y. A signal BlASe is supplied to the gate of the transistor 61 y. A signal BLCRL is supplied to the other ends of the current paths of the transistors 61 x, 61 y. The transistors 61 x, 61 y are turned on so as to complement the transistors 61 v, 61 w according to signals BlASo, BlASe, thereby supplying a signal BLCRL to the unselected bit lines.
Each of the above signals and voltages is generated by the control signal and control voltage generating circuit 7 of FIG. 2 . Under the control of the control signal and control voltage generating circuit 7 , the operation below will be carried out.
The memory, which is a multivalued memory, enables two bits of data to be stored in one cell. The switching between the two bits is effected according to the address (a first page, second page).
(Description of Operation)
With the above configuration, the operation will be explained.
FIG. 6A shows the relationship between the data in a memory cell and the threshold voltage of the memory cell. When an erase operation is carried out, the data in the memory cell becomes “0.” When a first page is written into, the data in the memory cell becomes data “0” and data “1.” After a second page is written into, the data in the memory cell becomes data “0” to “3.” In the first embodiment, the data in the memory cell is defined as taking a lower threshold value to a higher one.
(Program and Program Verify)
In a program operation, first, an address is specified, thereby selecting the two pages of FIG. 3 . In the memory, of the two pages, programming can be done only in this order: the first page and then the second page. Therefore, first, the first page is selected according to the address. In recent years, a writing method with one program sequence including two program operations has been used in order to narrow the threshold voltage distribution in a write operation of a multivalued flash memory which stores a plurality of bits. With this method, in a first program operation, a verify potential lower than the original threshold voltage is set and a write and verify operation is carried out. After the first program operation is passed, a second program operation is carried out. In the second program operation, the verify potential is set to the original value and a write and verify operation is carried out. In the method, the memory cell written into is written into again and a threshold voltage a little higher than the threshold voltage at which the preceding writing was done is set. This makes the degree of variability of the threshold voltage in a write operation small, with the result that the threshold voltage distribution is small. In the case of a NAND flash memory, of a plurality of cells connected to the same word line, half of them are written into simultaneously. Therefore, in a write verify loop, many cells have lower threshold voltages in the first verify operation. Thus, the source line is floating. The cells which have been written into first have their threshold voltages determined in this state. Then, after the other cells have been written into, the source line is fixed to a specific potential. As result, it seems that the threshold voltages of the cells first written into have gotten lower, which prevents the threshold voltage distribution from widening. An increment ΔVpgm in the write voltage in the first write operation is made larger and an increment ΔVpgm in the write voltage in the second write operation is made smaller, thereby speeding up the write operation.
In the first embodiment, too, a program operation is performed using the above method. FIG. 8 shows a first page write operation and FIG. 9 shows a second page write operation. Both of the first and second page write operations include two program and verify operations. FIGS. 10A , 10 B, and 11 show the contents of each data cache in the first page write operation. FIGS. 12A , 12 B, 13 A, and 13 B show the contents of each data cache in the first page write operation. In the figures, “L” means the low level and “H” means the high level.
(First Page Write Operation)
First, the first page write operation will be explained by reference to FIGS. 8 , 10 A, 10 B, and 11 .
(First Page Data Load) (S 10 )
First, writing data is externally inputted and is stored in the PDCs of all of the data storage circuits 10 . When data “1” meaning that no writing is done is externally inputted, the node N 1 a of the PDC shown in FIG. 1 is set to the high level. When data “0” meaning that writing is done is externally inputted, the node N 1 a of the PDC is set to the low level. Hereinafter, it is assumed that the data in the PDC is the potential at the node N 1 a and the data in the DDC is the gate potential of the transistor 61 r.
(First Page Data Cache Setting) (S 11 )
When a write command is inputted, the signal DTG goes high for a moment and the transistor 61 s constituting the DDC is turned on for a moment. As a result, the data in the PDC is copied into the DDC via the transistor 61 s. Therefore, the gate potential of the transistor 61 r goes high ( FIG. 10A ).
(First Page Program for the First Time) (S 12 )
Next, the potential of the signal BLC 1 , BLCLAMP, BLSo, or BLSe is set to Vdd+Vth (Vdd: power supply voltage (e.g., 3 V or 1.8 V, however, not restricted to this voltage), Vth: the threshold voltage of the n-channel MOS transistor). Then, the transistor 61 h turns on. As a result, when data “1” meaning that the PDC is not to be written into is stored in the PDC, the bit line goes to Vdd. When data “0” meaning that the PDC is to be written into is stored in the PDC, the bit line goes to Vss (ground potential). The cells in the unselected pages (their bit lines unselected) connected to the selected word line must not be written into. For this reason, the bit lines connected to those cells are set to Vdd as is data “1”. Here, when Vdd is supplied to the select line SG 1 of the selected block, Vpgm (20 V) is supplied to the selected word line, and Vpass (10 V) is supplied to the unselected word lines, if the bit line is at Vss, writing is done because the channel of the cell is at Vss and the word line is at Vpgm. On the other hand, if the bit line is at Vdd, Vpgm causes the channel of the cell to be at about Vpgm/2 through coupling. This prevents the memory cells whose bit lines are at Vdd from being programmed.
As shown in FIG. 6B , when the data in the first page is “0,” the data in the memory cell is set to “1.” When the data in the first page is “1,” the data in the memory cell remains at “0.”
After the writing is completed, the word lines at the potentials Vpgm and Vpass are returned to the original ones. In this recovery operation, the operation below is carried out.
(Exchange of Data Between PDC and DDC)
The signal BLPRE is set at Vdd temporarily and the signal VPRE is set at Vssw, thereby setting the TDC at Vss. Then, the signal VREG is set at Vdd and the signal REG is made high temporarily, thereby turning on the transistor 61 q. If the DDC has stored the high level, the transistor 61 r turns on, which sets the TDC at Vdd via the transistors 61 r, 61 q. If the DDC has stored the low level, the transistor 61 r is off, with the result that the TDC remains at Vss. By this operation, the data in DDC is copied into the TDC. Next, the signal DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Thereafter, the signal BLC 1 is made high temporarily, thereby copying the data in the TDC into the PDC. As a result, the data in the PDC moves to the DDC and the data in the DDC moves to the PDC ( FIG. 10B ).
(First Page Program Verify for the First Time) (S 13 )
In a first page program verify, a verify potential of “a*′” is applied to the selected word line as shown in FIG. 6B . The original verify potential “a′” is made a little higher than the read level. However, the first verify potential “a*′” for the first page program is made a little lower than the original verify potential “a′”.
Next, a voltage of Vread is supplied to the unselected word lines in the selected block and to the select line SG 1 , and the signal VPRE is set to Vdd, the signal BLPRE is set to Vdd+Vth, the signal BLCLAMP is set to, for example, 1 V+Vth in the data storage circuit of FIG. 1 , thereby precharging the bit line to, for example, 1 V. Thereafter, the select line SG 2 on the source side of the cell is made high. When the threshold voltage of the cell is higher than “a*′”, the cell turns off. Therefore, the bit line remains high. When the threshold voltage of the cell has not reached “a*′”, the cell turns on. Therefore, the bit line goes to Vss.
Thereafter, the signal BLCLAMP is set to Vss, the signal VPRE is set to Vdd, and the signal BLPRE is set to Vdd+Vth, thereby charging the TDC to Vdd. Then, the signal BLCLAMP is set to, for example, 1 V+Vth. Then, if the bit line is at the low level, the TDC goes to the low level. If the bit line is at the high level, the TDC remains high.
Here, when writing is done, the low level is stored in the DDC. When writing is not done, the high level is stored in the DDC. For this reason, when the signal VREG is set at Vdd and the signal REG is made high temporarily, if writing is not done, the TDC is forced to go to the high level. Thereafter, the signal DTG is made high temporarily, thereby copying the data stored in the PDC into the DDC. Then, with the signal BLC 1 at the high level, when the cell has reached the threshold voltage “a*′” or when writing is not done, the high level is latched in the PDC. Only when the threshold voltage of the cell has not reached “a*′”, the low level is latched in the PDC ( FIG. 10B ).
When the PDC is at the low level, the write operation is carried out again and the program operation and verify operation are repeated until the data in all of the PDCs have reached the high level (S 14 to S 12 ). At this time, the voltage Vpgm of the program is increased in steps of, for example, +0.4 V.
In this way, when the data in all of the PDCs are high, a second write operation of the first page is executed.
(First Page Data Cache Setting for the Second Time) (S 15 ) ( FIG. 11 )
In a state where the data in all of the PDCs are at the high level, the same operation as described above is executed and the data in the PDC is replaced with the data in the DDC. That is, the data stored in the DDC is transferred to the PDC. The data in the DDC is the data originally stored in the PDC. When writing is not done, the DDC holds data “1.” When writing is done, the DDC holds data “0.”
In this state, a second first-page program (S 16 ) and a second first-page program verify (S 17 ) are executed as in the above operation. Here, the verify level in the verify operation is “a′”, the original verify level ( FIG. 6C ).
Thereafter, when the PDC is at the low level, the write operation is carried out again and the program operation and verify operation are repeated until the data in all of the PDCs have reached the high level (S 18 to S 16 ) ( FIG. 11 ). At this time, an increment ΔVpgm in the voltage Vpgm of the program is made smaller than the first program operation and is increased in steps of, for example, +0.2 V.
In this way, after the data in the first page is written, the data in the second page is written.
(Second Page Write Operation)
Next, a second page write operation will be explained by reference to FIGS. 9 , 12 A, 12 B, 13 A, and 13 B.
(Second Page Data Load) (S 20 )
As in the first page program, in the second page program, writing data is externally inputted and stored in the PDCs of all of the data storage circuits 10 .
(Internal Data Load for the First Time) (S 21 ) ( FIG. 12A )
As shown in FIG. 7A , in a case where the data in the memory cell is “0” as a result of the first page write operation (or where the first page has not been written into), when the data in the second page is “0” (meaning that writing is to be done), the data in the memory cell is set to “3”; and when the data in the second page is “1” (meaning that writing is not to be done), the data in the memory cell is allowed to remain “0.” In addition, in a case where the data in the memory cell is “1” as a result of the first page write operation (or where the first page write has been written into), when the data in the second page is “0” (meaning that writing is be done), the data in the memory cell is set to “2”; and when the data in the second page is “1” (meaning that writing is not to be done), the data in the memory cell is allowed to remain “1.” Therefore, it is necessary to make a check to see if the data in the memory cell is “0” or “1”, before the data in the second page is written into the memory cell.
To do this, a potential of “a” is applied to the word line, thereby carrying out a read operation in an internal data load operation as shown in FIG. 6A . Next, the read potential Vread is supplied to the unselected word lines in the selected block and the select line SG 1 and a potential similar to that in the first page write operation is supplied to the signals VPRE, BLPRE of the data storage circuit 10 , thereby precharging the bit line. Thereafter, the select line SG 2 on the source side of the cell is made high. When the threshold voltage of the memory cell is higher than “a,” the cell turns off, with the result that the potential of the bit line remains high. On the other hand, when the threshold voltage of the memory cell is lower than “a,” the cell turns on, with the result that the potential of the bit line is at Vss. While the bit line is being discharged, the signal DTG is set to the high level temporarily, thereby copying the data in the PDC into the DDC ( FIG. 12A ).
Next, as in the first page write operation, after the TDC is charged to Vdd, the signal BLCLAMP is set to, for example, 1 V+Vth, thereby turning on the transistor 61 t. When the potential of the bit line is at the low level (or when the data in the memory cell is “0”), the TDC goes to the low level; and when the potential of the bit line is at the high level (or when the data in the memory cell is “1”), the TDC remains high.
When writing is done, the low level is latched in the DDC. When writing is not done, the high level is latched in the DDC. Therefore, when the signal VREG is set to Vss and the signal REG is made high temporarily, if writing is not done, the transistors 61 r, 61 q turn on, forcing the TDC to go to the low level. Thereafter, the DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Then, when the signal BLC 1 is made high, it is only when data “2” is written into the memory cell that the high level is latched in the PDC. When data is not written into the second page or when data “3” is written into the memory cell, the PDC goes to the low level.
Thereafter, an exchange of the data between the PDC and the DDC is made and the writing data is latched in the PDC. Only when data “2” is written into the memory cell, the high level is latched in the DDC.
(Second Page Program for the First Time) (S 23 ) ( FIG. 12B )
In a first second-page program, when the high level is latched in the PDC in the same operation as the first first-page program, data is not written into the memory cell. When the low level is latched in the PDC, data is written into the memory cell.
When the writing has been completed, the potentials of the word lines set at Vpgm and Vpass are returned to the original potentials. During the recovery operation, an exchange of the data between the PDC and the DDC is made as in the first-page program.
(First Second-page Program Verify: Verification of Data “2”) (S 24 )
In the second page program verify operation, when it is verified whether data “2” has been written into the memory cell in the same manner as in the first first-page program verify operation, the verification cannot be made correctly. Specifically, since the threshold voltage of a cell in which data “3” has been written is higher than the threshold voltage of a memory cell in which data “2” has been written, even when data “2” has been written insufficiently, the data is passed. Therefore, the data “2” is verified as described below.
Whether data “2” has been written into the memory cell is verified as follows. As shown in FIG. 7A , a verify potential of “b*′” is supplied to the selected word line. The original verify potential “b′” for data “2” is made a little higher than the read level. However, the first verify potential “b*′” in a program verify operation is a little lower than the original verify potential “b′.”
Next, the read potential Vread is supplied to the unselected word lines in the selected block and the select line SG 1 and the signal BLC 1 of the data storage circuit of FIG. 1 is set to Vdd+Vth. In addition, the transistors 61 t and 61 v or 61 w are turned on, thereby precharging the bit line. It is only the bit line to which a memory cell into which data “2” has been written is connected that is precharged. That is, when the high level has been latched in the PDC, the bit line is precharged. Thereafter, the select line SG 2 on the source side of the cell is made high. When the threshold voltage is higher than “b*′,” the cell turns off. Therefore, the potential of the bit line remains at the high level. When the threshold voltage “b*′” has not been reached, the cell turns on, with the result that the potential of the bit line goes to Vss.
Thereafter, the TDC is charged to Vdd as described above. Then, the specific voltage is supplied to the signal BLCLAMP for making transistor 61 t. When the potential of the bit line is low, the TDC goes low. When the potential of the bit line is high, the TDC remains high. As shown in FIG. 12B , when writing is done, the low level is latched in the DDC. When writing is not done, the high level is latched in the DDC. Therefore, when the signal VREG is set to Vcc and the signal REG is made high temporarily, if writing is not done, the TDC is forced to go to the high level. Thereafter, the DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Then, when the signal BLC 1 is made high, it is when the cell has reached the threshold voltage or when writing is not done that the high level is latched in the PDC. In addition, it is when data “2” has been written into the memory cell and the threshold voltage “b*′” has not been reached that the low level is latched in the PDC.
(First Second-page Program Verify: Verification of Data “3”) (S 25 )
Whether data “3” has been written into the memory cell is verified with a verify level of “c*′” as in the first first-page program verify operation. The verify level “c*′” is set a little lower than the level “c′” in the original verify read. After data “2” is verified, data indicating whether to write or not is latched in the PDC. When data “2” is written into the memory cell, the high level is latched in the DDC. Therefore, before the verification, the following operation is carried out, thereby making an exchange of the data between the PDC and the DDC.
(Exchange of Data Between PDC and DDC) First, the signal BLPRE is set to Vdd temporarily and the signal VREG is set to Vss, thereby setting the TDC to Vss. Next, the signal VREG is set to Vdd and the signal REG is made high temporarily, if the DDC is at the high level, the TDC is at Vdd. If the DDC is at the low level, the TDC remains at Vss. That is, the data in the DDC is copied into the TDC. Next, the signal DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Thereafter, the signal BLC is made high temporarily, thereby copying the data in the TDC into the PDC. As a result, the data stored in the PDC is transferred to the DDC and the data stored in the DDC is transferred to the PDC.
When the PDC is at the low level, the write operation is carried out again and the program operation and verify operation are repeated until the data in all of the PDCs has reached the high level (S 26 to S 23 ). At this time, the program voltage Vpgm is increased in steps of, for example,+ 0 . 4 V.
(Second Internal Data Load) (S 27 ) ( FIG. 13A )
As shown in FIG. 7A , in a first program, data “2” and data “3” are written into the memory cell. The threshold voltages of data “2” and data “3” are set lower than the original threshold voltage. Therefore, in a second program, data “2” and data “3” are written to the proper threshold voltage as shown in FIG. 7B . However, after the first program and program verify have been completed, the data in all of the PDCs have reached the high level, with the result that the writing data disappears. Therefore, a read operation is carried out to see if data “2” or data “3” has been written into the memory cell.
First, a read potential of “b” (“b”<“b′”) or the first verify potential “b*′” is supplied to the word line WL, thereby carrying out a read operation (S 27 ). From this, it is determined whether the memory cell is a cell into which data “2” and data “3” have been written. However, a cell into which data “2” has been written has been written only to the threshold voltage “b*′” lower than the original one. For this reason, a cell into which data “2” has been written might not be found. However, since in a cell into which data “2” has been written, the DDC is also at the high level as shown in FIG. 12B , a cell into which data “2” has been written can be recognized.
A concrete operation of a second internal data load is as follows. First, the read potential “b” is supplied to the selected word line. Then, the read potential Vread is supplied to the unselected word lines in the selected block and the select line SG 1 . The voltage in precharging the bit line is supplied to the signals VPRE, BLPRE of the data storage circuit 10 , thereby precharging the bit line. Thereafter, the select line SG 2 on the source side of the cell is made high. When the threshold voltage of the memory cell is higher than “b” or “b*,” the cell turns off. Therefore, the potential of the bit line remains high. On the other hand, when the threshold voltage of the memory cell is lower than “b” or “b*′,” the cell turns on, with the result that the potential of the bit line goes to Vss.
Next, after the TDC is charged to Vdd, the aforementioned potential is supplied to the signal BLCLAMP, thereby enabling the potential of the bit line to pass through via the transistor 61 t. When the potential of the bit line is at the low level, the TDC goes to the low level. When the potential of the bit line is at the high level (the threshold voltage of the memory cell is higher than “b” or “b*′”), the TDC goes to the high level. In a case where data “2” is written into the memory cell, the high level is latched in the DDC. In other cases, the low level is latched in the DDC ( FIG. 13A ). Therefore, when the signal VREG is set to Vdd and the signal REG is made high temporarily, if the data “2” is written into the memory cell, the TDC is forced to go high. Thereafter, when the signal BLC 1 is made high, it is only when data “2” is written into the memory cell or when data “3” is written into the memory cell that the high level is latched in the PDC.
(Second-page Data Cache Setting for the Second Time) (S 28 )
When data is written into the second page, the high level is latched in the PDC. When data is not written into the second page, the low level is latched in the PDC. Therefore, the data in the PDC must be inverted. To do this, the following operation is carried out.
(Exchange of Data Between PDC and DDC)
First, the signal BLPRE is set to Vdd temporarily and VPRE is set to Vss, thereby setting the TDC to Vss. Next, the signal VREG is set to Vdd and the signal REG is made high temporarily. When the DDC is at the high level, the TDC goes to Vdd. When the DDC is at the low level, the TDC remains at Vss. That is, the data in the DDC is copied into the TDC. Next, the signal DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Thereafter, the signal BLC 1 is made high temporarily, thereby copying the data in the TDC into the PDC.
(Exchange of Data Between PDC and DDC: Transfer of Inverted Data from DDC to PDC)
First, the signal BLPRE is set to Vdd temporarily and the signal VPRE is set to Vdd, thereby setting the TDC to Vdd. Next, the signal VREG is set to Vss and the signal REG is made high temporarily. When the DDC is at the high level, the TDC goes to Vss. When the DDC is at the low level, the TDC remains at Vdd. That is, the data in the DDC is inverted and copied into the TDC. Next, the signal DTG is made high temporarily, thereby copying the data in the PDC into the DDC. Therefore, the signal BLC 1 is made high temporarily, thereby copying the data in the TDC into the PDC. As a result, the writing data stored in the PDC is reversed and transferred to the PDC and the data stored in the DDC remains unchanged. Therefore, when the second page is written into, the low level is latched in the PDC. When the second page is not written into, the high level is latched in the PDC.
(Second Page Program for the Second Time) (S 29 ) ( FIG. 13B )
The second second-page program operates in the same manner as the first second-page program. That is, when the high level is latched in the PDC, the second page is not written into. When the low level is latched in the PDC, the second page is written into.
(Verify Operation of Data “2” and Data “3” for the Second Time) (S 30 , S 31 )
In the second page program, a second verify operation of data “2” and data “3” is the same as the first verify operation of data “2” and data “3” except for the verify potential. Specifically, in the second verify operation, the original verify potentials “b′” and “c′” are applied to the word line as shown in FIG. 7B .
When the PDC is at the low level as a result of the verify operation, the write operation is carried out again and the program operation and verify operation are repeated until the data in all of the PDCs have reached the high level (S 32 to S 29 ). At this time, an increment in the program voltage Vpgm is made smaller than the first ΔVpgm. For example, when the program voltage is increased in units of +0.4 V in the first verify operation, the program voltage is increased in units of +0.2 V in the second verify operation.
In the second write operation, the data is written into the memory cell as shown in FIG. 7B .
(Read Operation)
(Second Page Read) ( FIG. 14A )
In a second page read operation, the potential “b” in a read operation is applied to the selected word line. Next, the read potential Vread (e.g., 4.5 V) is applied to the unselected word lines in the selected block and the select line SG 1 . The signal VPRE is set to Vdd and a specific voltage is supplied to the signal BLPRE, BLCLAMP, thereby setting the TDC of the data storage circuit 10 to the high level as described above and precharging the bit line. Thereafter, the select line SG 2 on the source side of the cell is made high. When the threshold voltage of the memory cell is higher than “b,” the cell turns off, with the result that the bit line remains high. On the other hand, when the threshold voltage of the memory cell has not reached “b,” the cell turns on, with the result that the bit line goes to Vss. The data in the memory cell and the threshold voltage of the memory cell are defined as shown in FIG. 6A . Therefore, when the data in the memory cell is “0”, “1”, the TDC goes to the low level. When the data in the memory cell is “2”, “3”, the TDC remains at the high level.
Next, the potential of the TDC is transferred to the PDC. When the data in the memory cell is “0”, “1”, the low level is latched in the PDC. When the data in the memory cell is “2”, “3”, the high level is latched in the PDC ( FIG. 14A ). The data read from the PDC onto the data line IO is inverted at, for example, the data input/output buffer 4 . Therefore, when the data in the memory cell is “0”, “1”, the resulting data is data “1.” When the data in the memory cell is “2”, “3”, the resulting data is data “0.” The above operation is the same as reading from a memory that stores binary data.
(First Page Read) ( FIG. 14B )
When the data outputted in the first page read operation is “1,” as shown in FIG. 6A , the data in the memory cell lie in separate regions, “0” and “3.” Therefore, it is necessary to determine whether the data in the memory cell is “2” or less, or “3” and then determine whether the data in the memory cell is “0”, or “2” or more.
(Read Operation (1))
First, it is determined whether the data in the memory cell is “2” or less, or “3.” To do this, a read potential of “c” is applied to the word line, thereby reading the data in the memory cell onto the bit line. The read-out data is stored in the TDC and then transferred to the PDC. As a result, it is only when the data in the memory cell is “3” that the high level is latched in the PDC. In addition, it is when the data in the memory cell is “0”, “1”, “2” that the low level is latched in the PDC.
(Read Operation (2))
Next, it is determined whether the data in the memory cell is “1”, or “2” or more. To do this, a read potential of “a” is applied to the word line, thereby reading the data in the memory cell onto the bit line. As a result, when the data in the memory cell is “0,” the potential of the bit line goes to the low level. When the data in the memory cell is “1”, “2”, “3”, the potential of the bit line goes to the high level.
While the bit line is being discharged, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Then, after the potential of the bit line is transferred to the TDC, the signal VREG is set to Vss and the signal REG is made high temporarily. When the DDC is at the high level, the TDC is forced to go to the low level. As a result, when the data in the memory cell is “0”, “3”, the TDC goes to the low level. When the data in the memory cell is “1”, “2”, the TDC goes to the high level.
Next, these TDC's potentials are read into the PDC. When the data in the memory cell is “0”, “3”, the low level is latched in the PDC. When the data in the memory cell is “2”, “3”, the high level is latched in the PDC. The data read from the PDC onto the data line IO is inverted at, for example, the data input/output buffer 4 . Therefore, when the data in the memory cell is “0”, “3”, data “1” is outputted. When the data in the memory cell is “1”, “2”, data “0” is outputted.
In the first embodiment, the data storage circuit 10 has the PDC, DDC, and TDC. The externally inputted writing data is manipulated at the PDC, DDC, and TDC, which reproduces the data. As a result, a data cache for holding writing data need not be provided, which reduces the size of the circuit configuration.
Furthermore, after the writing data is loaded into the data storage circuit 10 , the same data need not be loaded again. Consequently, the write operation can be made faster.
Second Embodiment
Next, a second embodiment of the present invention will be explained.
In the first embodiment, at the time of the second-page program, two write operations have been carried out by the pass write method in each of the operation of writing data “2” and the operation of writing data “3.” However, when data “3” is written, writing may be done to the original threshold voltage “c′” in the first write operation in the second page program and only data “2” may be written by the pass write method in the second write operation.
FIG. 15 shows the second embodiment. In FIG. 15 , the same parts as those in FIG. 9 are indicated by the same reference numerals. FIG. 15 shows only the second page program operation.
A first second-page program, a program for data “2” is written to “b*′” a little lower than the original threshold voltage as in the first embodiment. In contrast, a program for data “3” is written to the original threshold voltage “c′.” Therefore, to verify data “3,” “c′” is supplied as a verify potential to the word line (S 25 ). In this way, data “3” is written to the original threshold voltage.
Since data “3” has been written to the original threshold voltage, only data “2” is written in the second second-page program. After the first program, the externally inputted writing data is not left in the data storage circuit 10 . However, when data “2” has been written, the DDC is at the high level after the first write operation ( FIG. 13A ). Therefore, the data in the DDC is reversed and transferred to the PDC, thereby enabling the data in the PDC to be used as writing data (S 28 ). Therefore, an internal data load, that is, a read operation using the read potential “b” or “b*′” in the first embodiment can be omitted.
As described above, after the data cache is set, a second program is carried out (S 29 ). This program is for setting data “2” to the original threshold voltage. Therefore, only a verify operation using the verify potential “b′” is executed. When all of the PDCs go high as a result of the program and verify operation, the write operation is completed.
In the second embodiment, since data “3” is written to the original threshold voltage in one program operation, the threshold voltage distribution of data “3” widens. However, the number of verify operations of data “3” is reduced, which enables high-speed writing.
Furthermore, after the first second-page program, the data in the DDC is inverted and transferred to the PDC, which enables the second program to be executed using the data in the PDC as writing data. Therefore, an internal load, that is, a read operation using the read potential “b” or “b*′” in the first embodiment can be omitted. Consequently, the program time can be shortened.
In the second embodiment, when data “3,” the largest one of the 4-valued data, is written, writing is done in one program. However, data written in one program is not limited to data “3.” Specifically, even when data larger than 4-valued one is written, the second embodiment may be applied to writing the largest one of the writing data items.
Third Embodiment
Next, a third embodiment of the present invention will be explained. In the first and second embodiment, 4-valued data has been written. Using the data storage circuit 10 configured as shown in FIG. 1 , data larger than 4-valued (2 bits of) data may be stored in the memory cell.
An algorithm for writing data larger than 4-valued data will be explained. The following writing method has been proposed in order to prevent the threshold voltage of the memory cell from fluctuating as a result of the data in adjacent cells being varied due to the capacitance between floating gates.
For example, in a 4-valued memory cell in which data is defined as “0”, “1”, “2”, “3” in ascending order of threshold voltage, when the first page is written into, a cell with data “0” is set to “2” with a threshold voltage of “2*′” lower than the original transistor. Then, after the first page of the adjacent cells is written into, “2*′” is returned to the original threshold voltage “2.” When the threshold voltage of the cell rises due to the capacitance between the floating gates (FG-FG) of the adjacent cells, the threshold voltage does not change much in writing to the original threshold voltage “2.” When the threshold voltage does not rise due to the FG-FG capacitance, the threshold voltage rises in writing to the original threshold voltage “2”, with the result that the threshold voltage becomes constant. In the third embodiment, an example of 8-valued data in a write operation will be explained.
A schematic configuration of a nonvolatile semiconductor memory device according to the third embodiment is the same as that of each of the first and second embodiments.
FIG. 16 shows the configuration of a memory cell array and a data storage circuit. The configuration of the memory cell array and data storage circuit is almost the same as that of FIG. 3 except that 3 bits of data are stored in each memory cell.
FIGS. 17A , 17 B, 17 C, 18 A, and 18 B show operations in the third embodiment. FIG. 19 shows the order in which the memory cells are written into. In FIG. 19 , for convenience's sake, one NAND cell is composed of four memory cells connected in series.
FIG. 18B shows the correspondence between the threshold voltage and data in a memory cell in the case of 8-valued data. In the case of 8-valued data, the data in the memory cell is set to, for example, “0”, “1”, “2,” . . . , “7” in ascending order of threshold voltage. When the data in the memory cell is erased, the data in the memory cell becomes “0.” When the first page is written into, the data in the memory cell becomes “0” or “4.” When the second page is written into, the data in the memory cell becomes “0”, “2”, “4”, “6.” Furthermore, When the third page is written into, the data in the memory cell becomes “0”, . . . , “7.”
For the sake of simplification, as shown in FIG. 17C , explanation will be given about a case where an additional one bit of data is written into a memory cell into which 4-valued or 2 bits of data have been stored.
FIG. 17A shows a state before the data in the second page is written after the data in the first page is written (after write orders 1 to 4 in FIG. 19 ). FIG. 17B shows a state after the data in the first page is written into adjacent cells. Since these write operations are the same as in the first and second embodiments, explanation of them will be omitted. In write orders 5 and 6 in FIG. 19 , after the data in the second page is written, the data in the first page is written into memory cells 5 , 6 adjacent to memory cells 3 , 4 in the bit line direction. Thereafter, the data in the second page is written into memory cells 3 , 4 (write orders 9 , 10 in FIG. 19 ). FIG. 17C shows a state after the data in the second page is written before the data in the third page is written (after write order 10 in FIG. 19 ). The following is an explanation of a method of storing an additional one bit of data in a state where 4-valued or 2 bits of data have been stored.
FIG. 20 shows a case where data is written into cells adjacent to the second page after the data in the second page is written. As in write order 11 of FIG. 19 , the data in the second page has been written into memory cell 4 as in write order 10 of FIG. 19 immediately before the data in the third page is written into memory cell 1 . After the writing is completed, the threshold voltage distribution of memory cell 1 is as shown in FIG. 18A .
In a cell into which data “2”, “4”, “6” are written, writing is done to the original verify levels of the third page, “b”, “d′”, “f′”. To do this, first, the potential of the word line is set to “a,” thereby reading the data written in the memory cell ( FIG. 20 (S 41 )). FIG. 22A shows the data read in the read operation. When the data in the memory cell takes the value other than “0,” data “1” is latched in the PDC. Thereafter, the data cache is operated, thereby setting the PDC as shown in FIG. 22B (S 42 ). As a result, when the data written into the memory cell is “2”, “4”, “6”, data “0” is latched in the PDC.
As shown in FIG. 18A , there may be a case where writing has been done to verify potentials “b*′”, “d*′”, “f*′” lower than the original verify potential in the second page write operation. Thereafter, the threshold voltage may have risen due to the adjacent cells written into. In addition, there are cells which have reached the original verify potentials “b′”, “d′”, “f′”. Therefore, first, a verify operation is carried out with the original verify potentials “b′”, “d′”, “f′” (S 43 , S 44 , S 45 ).
(Verifying a Cell with the Highest Threshold Voltage)
First, a cell with the highest threshold voltage, that is, a cell into which data “6” has been written is verified. In this case, a potential of “f” a little higher than the potential “f” in a read operation is applied to the selected word line. The read potential Vread is supplied to the unselected word lines in the selected block and the select line SG 1 and a specific voltage is supplied to the signal BLCLAMP and signal BLPRE of the data storage circuit 10 , thereby precharging the bit line. When the threshold voltage of the memory cell is higher than “f′”, the cell turns off. Therefore, the bit line remains high. When the threshold voltage of the memory cell is lower than “f′”, the cell turns on. Therefore, the bit line goes to Vss. While the bit line is being discharged, the TDC is set to Vss temporarily. Thereafter, the signal REG is made high, thereby turning on the transistor 61 q, which transfers the data in the DDC to the TDC.
Next, the signal DTG is made high temporarily, thereby turning on the transistor 61 s, which transfers the data in the PDC to the DDC. Thereafter, the signal BLC 1 is made high, thereby turning on the transistor 61 h, which transfers the data in the TDC to the PDC.
Next, the signal VPRE of the data storage circuit 10 is set to Vdd and the signal BLPRE is made high, thereby precharging the TDC to Vdd. Thereafter, the signal BLCLAMP is made high. When the bit line is at the low level, the TDC goes low. When the bit line is at the high level, the TDC goes high.
When writing is done, the low level is latched in the DDC. When writing is not done, the high level is latched in the DDC. Therefore, when the signal VREG is set to Vdd and the signal REG is made high, if writing is not done, the transistor 61 r turns on, with the result that the TDC is forced to go to the high level. Then, the data in the PDC is transferred to the DDC and the potential of TDC is transferred to the PDC. It is only when writing is not done or when data “6” has been written into the memory cell and the threshold voltage of the cell has reached the verify potential “f′” that the high level is latched in the PDC. In addition, it is only when the threshold voltage of the cell has not reached “f′” or when data “4” or “2” has been written into the memory cell that the low level is latched in the PDC.
(Verifying a Cell with an Intermediate Threshold Voltage) ( FIG. 20 (S 44 , S 45 ))
As in verifying a cell with the highest threshold voltage, it is difficult to verify a cell with an intermediate threshold voltage, that is, a cell into which data “2”, “4” have been written. The reason is that, since the threshold voltage of a cell into which a threshold voltage higher than a cell with an intermediate threshold voltage has been written is higher than the intermediate threshold voltage, the result of verifying the cell with the higher threshold voltage is also acceptable. To solve this problem, a read operation is carried out to determine whether there is any cell with a threshold voltage higher than the verify potential of the intermediate threshold voltage. If there is such a cell, the result of the verify operation must be determined to be unacceptable.
To do this, a potential of “d′” or “b′” a little higher than the potential “d” or “b” in a read operation is supplied to the selected word line. The read potential Vread is supplied to the unselected word lines in the selected block and the select line SG 1 and the specific voltage is supplied to the signal BLCLAMP and signal BLPRE of the data storage circuit 10 , thereby precharging the bit line. When the threshold voltage of the memory cell is higher than “d′” or “b′”, the cell turns off. Therefore, the bit line remains high. In addition, when the threshold voltage of the memory cell is lower than “d′” or “b′”, the cell turns on. Therefore, the bit line goes to Vss.
Next, the signal VPRE of the data storage circuit 10 is set to Vdd and the signal BLPRE is made high, thereby precharging the TDC to Vdd. Thereafter, a specific high level is supplied to the signal BLCLMP. When the bit line is at the low level, the TDC goes low. When the bit line is at the high level, the TDC goes high. Then, the data in the PDC is transferred to the DDC and the potential of the TDC is transferred to the PDC. It is when the threshold voltage of the cell is higher than “d′” or “b′”, that is, when the result of the verify operation is acceptable, or when data “6” has been written into the memory cell, or when data “4” or “6” has been written into the memory cell that the PDC goes to the high level.
Next, the potential of the word line is raised to a potential of “e” or “c” a little higher than “d′” or “b′”. The bit line goes to the high level, when the threshold voltage of the cell is equal to or higher than “d′” or “b′”. However, when the threshold voltage is lower than “e” or “c”, the cell turns on, with the result that the bit line goes to Vss. Therefore, since the cell turns on only when the threshold voltage is higher than “e” or “c”, the bit line remains high.
(Exchange of Data Between PDC and DDC)
While the bit line is being discharged, the TDC is set to Vss temporarily, the signal VREG is set to Vdd, and the signal REG is made high, thereby transferring the data in the DDC to the TDC. Then, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Thereafter, the data in the TDC is transferred to the PDC.
(Exchange of Data Between PDC and DDC: the Data in the DDC is Inverted and Transferred to the PDC)
The TDC is set to Vdd temporarily, the signal VREG is set to Vss, and the signal REG is made high, thereby inverting the data in the DDC and transferring the inverted data to the TDC. Thereafter, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Thereafter, the data in the TDC is transferred to the PDC.
(Exchange of Data Between PDC and DDC)
The TDC is set to Vss temporarily, the signal VREG is set to Vdd, and the signal REG is made high, thereby transferring the data in the DDC to the TDC. Then, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Thereafter, the data in the TDC is transferred to the PDC.
As a result of the operation, it is when the threshold voltage of the cell is lower than the potential “d′” or “b′” of the word line at the time of the discharging of the bit line that the DDC goes high. In addition, it is when the threshold voltage of the cell is higher than the potential “d′” or “b′” of the word line at the time of the discharging of the bit line that the DDC goes low. The data latched in the PDC is the data latched previously. That is, in the case of cells to be written into, data “0” is latched in them. In the case of cells not to be written into, data “1” is latched in them.
Next, the signal VPRE of the data storage circuit 10 is set to Vdd and the signal BLPRE is raised to a specific high level, thereby precharging the TDC to Vdd. Thereafter, a specific high level is supplied to the signal BLCLAMP. When the bit line is at the low level, the TDC goes low. When the bit line is at the high level, the TDC goes high. Here, when the signal VREG is set to Vdd and the signal REG is made high, if the high level is stored in the DDC, the TDC is forced to go to the high level. As a result, it is when the threshold voltage of the cell is lower than “d′” or “b′” or when the threshold voltage of the cell is higher than “e” or “c” that the TDC goes high. It is when the threshold voltage of the cell is higher than “d′” or “b′” or when the threshold voltage of the cell is lower than “e” or “c” that the TDC goes low. That is, it is when data “4” or “2” has been written into the memory cell and the result of the verify operation is acceptable that the TDC goes low. Thereafter, the data in the PDC is transferred to the DDC and the potential of the TDC is transferred to the PDC.
(Exchange of Data Between PDC and DDC)
The TDC is set to Vss temporarily, the signal VREG is set to Vdd, and the signal REG is made high, thereby transferring the data in the DDC to the TDC. Thereafter, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Then, the data in the TDC is transferred to the PDC.
(Exchange of Data Between PDC and DDC: the Data in the DDC is Inverted and Transferred to the PDC)
The TDC is set to Vdd temporarily, the signal VREG is set to Vss, and the signal REG is made high, thereby inverting the data in the DDC and transferring the inverted data to the TDC. Thereafter, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. Then, the data in the TDC is transferred to the PDC.
The TDC is set to Vss temporarily, the signal VREG is set to Vdd, and the signal REG is made high, thereby transferring the data in the DDC to the TDC. Thereafter, the signal DTG is made high temporarily, thereby transferring the data in the PDC to the DDC. The signal VREG is set to Vdd and the signal REG is made high. Then, when the high level is latched in the DDC, the TDC is forced to go to the high level. As a result, it is when data “4” or “2” has been written into the memory cell and the result of the verification is acceptable or when data “1” (writing unselected) has been latched that the TDC goes to the high level. Thereafter, the data in the TDC is transferred to the PDC.
(Program Operation) (S 47 )
A program operation is the same as the program operation in the first and second embodiments. When data “1” has been stored in the PDC, writing is not done. When data “0” has been stored, writing is done.
(Program Verify) (S 43 to S 46 , S 47 )
After the program, a verify operation is carried out with the original verify potentials “b′”, “d′”, “f′”. The program and verify operation is repeated until the data in all of the PDCs become “1”. The program and verify operation is the same as the verifying of the cell with the highest threshold voltage and the cell with the intermediate threshold voltage.
As a result of the program and verify operation, the threshold voltage distribution of data “0”, “2”, “4”, “6” in the memory cell is as shown in FIG. 18B .
(Third Page Write)
Next, the third-pate write operation will be explained by reference to FIG. 21 .
(Data Load, Read Operation, and Data Cache Setting)
Next, the writing data for the third page is externally loaded into the PDC (S 51 ). FIG.23A shows the data loaded into the PDC. After a write command is inputted, the potentials “a”, “d”, “f” in a read operation are supplied to the word line, thereby reading the data in the memory cell (S 52 to S 54 ). According to the data read out, the data cache is set (S 55 ). As a result, the data latched in the PDC is as shown in FIG. 23B . In FIG. 23B , data “1” means that writing is not selected and data “0” means that writing is selected.
(Program Operation) (S 56 )
A program operation is the same as the program operation in the first and second embodiments. When data “1” has been stored in the PDC, writing is not done. When data “0” has been stored, writing is done.
(Program Verify) (S 57 to S 60 )
After the program, a verify operation is carried out with the original verify potentials “a′”, “c′”, “e′”, “g′”. The verify operation is repeated until the data in all of the PDCs become “1” (S 61 to S 56 ). In the program verify operation, the verify operation with the verify potential “g′” is the same as the verifying of the cell with the highest threshold voltage. The verify operation with the verify potentials “a′”, “c′”, “e′” is the same as the verify operation with the intermediate threshold voltage. After those verify operations, the potential of the word line is set to the read voltages “b”, “d”, “f” and the data in the memory cell is read, thereby preventing the cells with a threshold voltage higher than the data just read from being accepted as the result of the verify operation.
With the third embodiment, a NAND flash memory storing 8-valued or three bits of data can be configured using a data storage circuit composed of three data caches. Therefore, a much larger volume of data can be stored with a smaller circuit configuration.
In the third embodiment, to simplify the operation, an additional one bit of data is stored in the state where 4-valued or two bits of data have been stored as shown in FIG. 17C , which enables 8-valued or three bits of data to be stored. In addition, the operation of the third embodiment may be applied to a case where an additional one bit of data is stored in the state where binary or one bit of data has been stored as shown in FIG. 17A , which enables 4-valued or two bits of data to be stored.
Furthermore, not only 8-valued or three bits of data but also 16-valued or more data can be written almost in the same operation as the third embodiment.
Fourth Embodiment
A fourth embodiment of the present invention is modified from the third embodiment. In the third embodiment, before the third page (the data in the third bit) is written into, the data in the memory cells in the second page and the first page (4-valued or two bits of data) has been written to the original verify potentials “b′”, “d′”, “f′”. However, this operation may be omitted, when there is room for the threshold voltage distribution. In this case, the operation shown in FIG. 20 is omitted and only the writing of data “1”, “3”, “5”, “7” in the third page shown in FIG. 21 is done.
With the fourth embodiment, it is not necessary to write the data in the memory cells in the second page and the first page to the original verify potentials “b′”, “d′”, “f′”, which enables the program operation to be carried out at higher speed.
Fifth Embodiment
In the first to fourth embodiments, the data storage circuit 10 is shared by two bit lines as shown in FIGS. 1 and 3 . The present invention is not limited to this.
FIG. 24 shows a fifth embodiment of the present invention. In the fifth embodiment, data storage circuits 10 are connected to the individual bit lines. With this configuration, the number of transistors acting as high-breakdown-voltage transistors can be halved. In the case of the configuration of FIG. 1 , high-breakdown-voltage transistors 61 x, 61 v are connected to both ends of the bit line BLo and high-breakdown-voltage transistors 61 y, 61 w are connected to both ends of the bit line BLe. The transistors 61 x , 61 y are transistors for supplying the potential of the signal BLCRL. The sizes of the transistors 61 x, 61 y , 61 v, 61 w are much larger than those of the transistors constituting the PDC and others. However, as shown in FIG. 24 , when the data storage circuits 10 are connected to the individual bit lines, the transistors 61 x, 61 y can be omitted. Therefore, even when the data storage circuits are connected to the individual lines, the chip size can be prevented from increasing. | A page mode multi-level NAND-type memory employs two different verify levels per data state and comprises a first data storage circuit which is connected to a memory cell and which stores externally inputted data of a first logic level or a second logic level, a second data storage circuit which is connected to the memory cell and which stores the data of the first logic level or second logic level read from the memory cell, and a control circuit which controls the memory cell and the first and second data storage circuits and which reproduces the externally inputted data and writing the data into the memory cell. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A COMPACT DISK APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates to laser protective eyewear for military, medical and industrial applications, and methods of manufacturing the same. The laser protective eyewear is capable of transmitting energy in the visible region and absorbing or reflecting energy at specific peak wavelengths. Furthermore, the laser protective eyewear can be manufactured by transferring or laminating one or more inorganic thin film optical coatings onto a polymeric base lens.
[0006] 2. Description of Related Art
[0007] Lasers have become important tools in industrial, medical and military applications. Applications range from laser cutting, to medical surgery, to targeting signals. Typical industrial lasers include but are not limited to Argon (operation wavelengths at 488 and 515 nm), YAG doubled KTP (operation wavelength at 532 nm), Ruby (operation wavelength at 694 nm), Alexandrite (operation wavelengths at700 to 820 nm), Diode (operation wavelength at 810 nm), Ga:As (operation wavelength at 850 to 900 nm), Ti:sapphire (operation wavelength at 680 to 1110 nm), and Nd:YAG (operation wavelength at 1064 nm).
[0008] Lasers, if operated without the use of laser protective eyewear (LPE) or a laser protective window, can cause permanent damage to the human eye. More particularly, lasers operating at certain wavelengths and energy levels can cause permanent eye damage and even blindness, depending on exposure and intensity (e.g., wavelengths from 180-315 nm can cause inflammation of the cornea, wavelengths from 315-400 nm can cause photochemical cataract, wavelengths from 400-780 nm can cause photochemical damage to the retina, and wavelengths from 780-1400 nm can cause cataract and retinal damage).
[0009] Current technology allows LPEs to be manufactured from glass or from injection molded polymer. Glass based LPEs have certain undesirable limitations, such as increased weight, reduced impact resistance and higher manufacturing costs. However, one advantage of glass eyewear is its ability to serve as a base substrate for high temperature thin film optical coatings using physical vapor deposition or ion assisted vapor deposition. Thin film optical coatings, because of their ability to have sharp optical transitions (unlike absorptive dyes), can be tuned to absorb or reflect specific narrow bands of light without significantly limiting the visible light transmission.
[0010] Polymeric laser protective eyewear is predominately manufactured using an optical thermoplastic such as nylon or polycarbonate. Polymeric LPEs have superior impact resistance, low weight, and lower manufacturing costs. However, while current polymeric laser filtering technology allows operators to be protected from harmful laser radiation, it greatly limits visible light transmission. Furthermore, with the current available technology, a user operating multiple laser types must purchase multiple pairs of LPEs to reflect the different operating wavelengths. Current polymeric LPEs that protect against multiple laser wavelengths have greatly reduced visible light transmissions.
[0011] Thus, a need still exists in the art for LPEs that are light, that provide high visible transmission, and that provide multi-wavelength rejection bands corresponding to peak laser wavelengths.
BRIEF SUMMARY OF THE INVENTION
[0012] The present disclosure is directed to a series of laser protective eyewear that transmit energy in the visible region and absorb or reflect energy at specific peak wavelengths. In one embodiment, the laser protective eyewear includes a polymeric base lens coated with one or more inorganic thin film optical coatings.
[0013] Furthermore, the present disclosure is directed to methods of manufacturing laser protective eyewear that transmit energy in the visible region and absorb or reflect energy at specific peak wavelengths. For example, in one embodiment, the laser protective eyewear is manufactured by applying one or more inorganic thin film optical coatings to a polymeric base lens. The one or more inorganic thin film optical coatings can be applied directly to the polymeric base lens, or indirectly via a transfer lens. Furthermore, in one embodiment of the present invention, the eyewear is manufactured to further include absorptive dye technology.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0014] 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, there is shown in the drawings certain embodiments of the present disclosure. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
[0015] In the drawings:
[0016] FIG. 1 illustrates a polymeric base lens.
[0017] FIG. 2 illustrates a laser protective lens manufactured in accordance with the teachings of the present invention.
[0018] FIG. 3 is a graph of the emission spectrum in accordance with an embodiment of the present invention.
[0019] FIG. 4 depicts a construction of one embodiment of the disclosed laser protective eyewear manufactured in accordance with the teachings of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] 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 to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. It should be understood that any one of the features of the invention may be used separately or in combination with other features. Other systems, methods, features, and advantages of the invention will be or become apparent to one with skill in the art upon examination of the drawings and the detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.
[0021] The present disclosure is directed to a series of laser protective eyewear (LPE) that selectively transmit energy in the visible region of the electromagnetic spectrum (e.g., between 400 and 780 nm) and that have selective absorption in the visible and near infrared regions of the electromagnetic spectrum (e.g., between 780 and 2000 nm). In one embodiment of the present invention, a series of novel polycarbonate laser eyewear have been developed that meet ANSI Z87.1 and Z136.7 for laser compliance. The eyewear is manufactured by applying on or more inorganic thin film optical coatings onto a polymeric base lens. In one embodiment, the base substrate of the polymeric lens is manufactured into an optical lens by injection molding.
[0022] In a further embodiment, as illustrated in FIG. 1 , a molded base lens 1 comprises a transparent polymer such as poly (methyl methacrylate) (PMMA), polystyrene, nylon, SAN, polyester, polyimide, polyepoxide, polyetherimide, polycarbonate or a polycarbonate copolymer. In one preferred embodiment, the base substrate of the polymeric lens is a transparent thermoplastic resin, such as, but not limited to, PMMA, polystyrene, nylon, SAN, polyester, polycarbonate or a polycarbonate copolymer.
[0023] In a preferred embodiment, as illustrated in FIG. 2 , the polymeric lens 1 is coated with an inorganic thin film optical coating 2 . FIG. 3 depicts the transmittance and absorbance of an inorganic thin film optical coating 2 that is an exemplary embodiment of the present disclosure. The thin film optical coating 2 exhibits high reflection in the red and near infrared regions of the electromagnetic spectrum. In at least one embodiment, the optical thin film coating 2 has a rejection band between approximately 532-580 nm and 700-1200 nm, and a transmission band between approximately 400-510 nm and 580-700 nm.
[0024] FIG. 4 depicts another embodiment of the disclosed laser protective eyewear manufactured in accordance with the teachings of the present invention. In this embodiment, the eyewear comprises a base polymeric lens 7 coated with an inorganic thin film optical coating 6 . The base polymeric lens 7 and inorganic thin film optical coating 6 are further coated by an optically clear encapsulant resin 5 . The optically clear encapsulant resin 5 can comprise any optically transparent polymers known in the art such as, but not limited to, transparent polyester, polyurethane, polyepoxide, poly(methyl methacrylate) (PMMA), or silicone. A second inorganic thin film optical coating 4 coats the optically clear encapsulant resin 5 . In one embodiment, the eyewear comprises multiple alternating layers of optically clear encapsulant resin and inorganic thin film optical coatings determined by a desired optical performance. Further, in some embodiments, an optically clear anti-scratch hardcoat 3 is the final coating of the LPE. The optically clear anti-scratch hardcoat 3 can comprise any optically transparent polymers known in the art such as, but not limited to, transparent polyester, polyurethane, polyepoxide, poly(methyl methacrylate) (PMMA), or silicone. In another embodiment, the resin encapsulants are cured using any method known in the art, such as thermal or ultraviolet (UV) curing.
[0025] In a further embodiment of the invention, the laser protective eyewear is manufactured by alternating optically clear encapsulant resins and inorganic thin film optical coatings until a desired optical performance is achieved. This interlayer stacking process avoids the complications associated with the internal stress and optical requirements of a multi-coating or multiple waveband optical thin film coating stack. Otherwise, a complex multiple layer thin film optical filter stack has an internal stress that is capable of bending a sheet of polymer or even glass, which can change the base curve of the resin lens. Furthermore, multiple rejection bands cannot be achieved in a single layer.
[0026] In another embodiment of the present invention, the laser protective eyewear is manufactured by laminating together multiple polymeric lenses. For example, each lens 1 is coated with an inorganic thin film optical coating 2 , as shown in FIG. 2 . The individual coated lenses are laminated together using an optically clear resin. The optically clear resin can comprise any optically transparent polymers known in the art such as, but not limited to, transparent polyester, polyurethane, polyepoxide, poly(methyl methacrylate) (PMMA), or silicone. Again, the lamination of separately coated lenses avoids the complications associated with the internal stress and optical requirements of a multi-coating or multiple waveband optical thin film coating stack.
[0027] In another embodiment of the present invention, the eyewear is manufactured by first applying the thin film optical coating 6 to a glass lens having the substantially same base curve as the base polymer lens 7 , and then transferring and bonding the inorganic thin film optical coating 6 onto the polymeric base lens 7 . Alternatively, in another embodiment of the present invention, the eyewear lens is manufactured by first applying the thin film optical coating 6 to a transfer lens having the substantially same curvature as the base polymer lens 7 , and then transferring and bonding the thin film optical coating 6 onto the polymeric base lens 7 . Furthermore, a release agent coating may be applied to the transfer lens prior to applying the inorganic thin film optical coating 6 . These transfer methods avoid the complications associated with the internal stress and optical requirements of a multi-coating or multiple waveband optical thin film coating stack.
[0028] In another embodiment of the present invention, inorganic thin film optical coatings, such as dichroic coatings, are applied via physical vapor deposition or ion assisted vapor deposition. These coatings are applied at temperatures ranging from approximately 200° C. to 300° C.; however, a standard thermoplastic polymer cannot be processed at these temperatures. Thus, first, the inorganic thin film optical coating is applied to a transfer lens. A release agent coating is applied to the transfer base lens before application of the inorganic thin film optical coating. The transfer lens acts as a temporary carrier for the coating and can be comprised of glass, ceramics, silicon wafer, or other materials with high temperature stability. Furthermore, the inorganic thin film optical coating is designed to be readily removable from the transfer lens.
[0029] After applying the inorganic thin film optical coating to the transfer lens, an optical adhesive is applied to the surface of the thin film optical coating. In one embodiment, the adhesive is partially cured, and then the optical coating and adhesive is transferred to the molded polymeric base lens. In another embodiment, the optical coating and adhesive are transferred to the polymeric base lens prior to curing, and then the adhesive is subsequently cured. Upon completion of the curing procedure, the transfer lens is easily removed and the thin film optical coating is transferred to the polymeric base lens. The transfer method can be carried out using an optical hot melt adhesive or liquid adhesive. The result is a polycarbonate LPE with at least one thin film optical coating. This method can be repeated so that the LPE comprises multiple alternating inorganic thin film optical coatings and optical adhesive layers as determined by a desired optical performance. In a further embodiment, the LPE is coated with an abrasion and chemically resistant hardcoat.
[0030] In one embodiment of the present invention, the LPE is manufactured by applying one or more inorganic thin film optical coatings directly onto the base substrate lens using physical vapor deposition or ion assisted vapor deposition. Physical vapor deposition and ion assisted vapor deposition optical coatings are applied from approximately 200° C. to 300° C.; however, a standard thermoplastic polymer cannot be processed at these temperatures. Therefore, to apply the optical coating directly onto the polymeric base lens, the polymer base lens should comprise a polymer with a vicat softening temperature above 200° C. Examples of such polymer families include polyimides, polyetherimides, polyepoxides, and polycarbonate copolymers.
[0031] In another embodiment of the present invention, the LPE is manufactured by applying one or more inorganic thin film optical coatings directly onto the base substrate lens using sputtering deposition or other coating techniques. Sputtering deposition, or other coating techniques with a sustained chamber temperature below 150° C., can be used to manufacture polymeric base lenses comprised of polymers with a vicat softening temperature below 150° C. Furthermore, using temperatures below 150° C. can allow for either a direct or transferred coating technique.
[0032] In another embodiment, inorganic or organic near IR suppressing dyes and pigments are incorporated into the polymer matrix of the thermoplastic eyewear before applying the inorganic thin film optical coating. In one embodiment of the present invention, additional visible dyes or pigments are added to absorb visible laser wavelengths, such as wavelengths at 532 nm and 690 nm. These visible dyes or pigments are added to control the chromaticity and visible radiation of the laser. Also, UV absorbers can be added so that the LPE absorbs in the ultraviolet region of the electromagnet spectrum (e.g. between 200 to 400 nm). The added dyes or pigments should exhibit a high absorbance in the radiation band of the laser and preferably low absorption in the visible region. In one embodiment of the present invention, the IR absorbers need to be purified to 99% purity to limit unwanted absorption. The absorbers are purified using recrystallization, column chromatography, or other purification techniques known to those killed in the art. Otherwise, if the purification is not fully completed, the absorbers exhibit reduced thermal stability. The final strength of the near IR absorption of the laser eyewear depends on the absorbance of the near IR dye or pigment, the purity of the absorber, the thickness of the window, and it's compatibility in the host resin. Common families of absorbers include, but are not limited to, metal dithiolenes, rylenes, porphyrins, tris amminium, phthalocyanines and naphthalocyanines. Phthalocyanines and naphthalocyanines are of particular benefit due to their thermal stability. Phthalocyanine dyes are light stable, exhibit excellent heat resistance, excel in the ability to absorb near infrared energy, and are compatible with multiple resin families. Mixtures of more than one absorber can be used to achieve broad absorption in the near infrared region. Optimization of the mixtures is known to those persons skilled in the art.
[0033] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that the invention disclosed herein is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims. | The present disclosure is directed to a thermoplastic laser protective eyewear, and methods of manufacturing said thermoplastic laser protective eyewear. In one embodiment, the laser protective eyewear transmits energy in the visible region and absorbs or reflects energy at peak wavelengths that correspond to commercially available industrial, military and medical lasers. | 6 |
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
This U.S. patent application is related to the following concurrently filed U.S. patent applications:
i) U.S. patent application Ser. No. 10/298,447, entitled USING FFT ENGINES TO PROCESS DECORRELATED GPS SIGNALS TO ESTABLISH FREQUENCIES OF RECEIVED SIGNALS, filed Nov. 18, 2002, now issued as U.S. Pat. No. 6,806,827;
ii) U.S. patent application Ser. No. 10/298,415, entitled SAVING POWER IN A GPS RECEIVER BY CONTROLLING DOMAIN CLOCKING, filed Nov. 18, 2002, currently abandoned;
iii) U.S. patent application Ser. No. 10/298,414, entitled AVOIDING INTERFERENCE TO A GPS RECEIVER FROM WIRELESS TRANSMISSIONS BY TIME MULTIPLEXING GPS RECEPTION, filed Nov. 18, 2002, now issued as U.S. Pat. No. 6,825,802; and
iv) U.S. patent application Ser. No. 10/298,444, entitled GPS RECEIVER, filed Nov. 18,2002, now issued as U.S. Pat. No. 6,778,135, wherein these related U.S. patent applications are incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
The present invention relates to a GPS receiver, and in particular to address translation logic operating to group post correlation data in memory in order to improve the efficiency of a fast Fourier transform of the data.
BACKGROUND OF THE INVENTION
The global positioning system (GPS) is based on an earth-orbiting constellation of twenty-four satellite vehicles each broadcasting its precise location and ranging information. From any location on or near the earth, a GPS receiver with an unobstructed view of the sky should be able to track at least four satellite vehicles, thereby being able to calculate the receiver's precise latitude, longitude, and elevation. Each satellite vehicle constantly transmits two signals, generally referred to as L 1 and L 2 . The L 1 signal from a satellite vehicle contains a unique pseudo-random noise code ranging signal (C/A code) with a chipping frequency of 1.023 MHz, system data with a bitrate frequency of 50 Hz, and an encrypted precise-code (y-code) with a chipping frequency of 10.23 MHz all being modulated onto a carrier frequency of 1575.42 MHz. The L 2 signal consists of the system data and y-code being modulated onto a carrier frequency of 1227.60 MHz.
In order to calculate a three-dimensional location, a receiver must determine the distance from itself to at least four satellite vehicles. This is accomplished by first determining the location of at least four satellite vehicles using ephemeris data received from the satellites. Once the locations of the satellites have been determined, the distance from the receiver to each of the satellites is calculated based upon the current estimate of receiver position. The measurement of the distance from the receiver to a satellite is based on the amount of time that elapsed between the transmission of a ranging signal from each satellite vehicle and the reception of that chip symbol by the receiver. In particular, the estimated position of the receiver is then corrected based upon a time epoch associated with the received ranging signal.
In order to acquire the L 1 or L 2 signal, the receiver must match the C/A code or y-code carried in the L 1 signal, or the y-code carried in the L 2 signal, with an internally generated code. For the C/A code, this is typically done by correlating the two signals by shifting the generated code through the 1023 possible time offsets of the C/A code until the generated code matches the C/A code carried in the L 1 signal. To improve the performance of the search, the generated code may be shifted at shorter intervals than a whole chip. For example, 2046 one-half chip positions may be searched. At the time offset when the generated code matches the C/A code carried in the L 1 signal, the two signals will cancel out, leaving only the carrier frequency and system data.
In addition to finding the time offset of the C/A code or y-code carried in the L 1 signal or the y-code carried in the L 2 signal, the frequency of the received L 1 or L 2 signal is typically determined. This may be done by generating a local L 1 or L 2 signal, and correlating this, together with the generated C/A or Y code with the received signal. Because of the movement of the satellite vehicles relative to the earth, the received frequency will experience a Doppler shift of +/−4,500 Hz from the transmitted frequency of the L 1 or L 2 signal. Another source of frequency uncertainty is the imperfection of the local oscillator, which typically can add a frequency offset of +/−20 ppm, or +/−30 kHz. However, a good part of this offset is due to variations in temperature, and may be modeled by a GPS receiver with a temperature sensor. With this modeling, the remaining temperature uncertainty could be around 10 kHz. Receiver movement may also cause a Doppler effect, however, this effect is usually insignificant when compared to the movement of the satellite vehicles in a commercial application. Due to the conventional method of the GPS signal detection, the receiver generated L 1 or L 2 signal needs to be within less that 500 Hz of the received signal for a successful search. Typically the frequency of the generated signal is incremented in 750 Hz intervals as the receiver searches for the correct code/carrier combination.
Therefore, a two-dimensional search of an approximately 30,000 Hz frequency range and the possible time offsets of the C/A code or the y-code must be made in order to acquire the L 1 or L 2 signal. Some GPS receivers have been designed to concurrently search all possible time offsets for the C/A code in the L 1 signal at a single frequency, thereby requiring an enormous number of correlators. After searching all 1023 or more time offsets at one frequency, the frequency is changed and the process is repeated until a satellite is found or the approximately 30,000 Hz frequency range has been searched. While this approach works well in most cases, new applications for GPS receivers are more likely to have access to a precise time source, narrowing the time, or code position, window that needs to be searched. At the same time, a drive to lower system cost by using cheaper oscillators with larger frequency errors maintains the need to quickly search a wide frequency range. Thus, there remains a need for a GPS receiver capable of concurrently searching the approximately 30,000 Hz range of frequencies to determine the precise frequency of the L 1 or L 2 signal, while having a modest number of correlators used to determine the time offset of the C/A code or the y-code carried in the L 1 or the y-code in carried in the L 2 signal.
SUMMARY OF THE INVENTION
The address translation logic of the present invention is incorporated in a global positioning system (GPS) receiver and operates to group data in memory based on translating the address from a direct memory access controller. The data includes post-correlated samples of the correlation of a signal with a generated frequency and a generated code having a plurality of time offsets. In general, the address translation logic organizes the data such that each element of the data associated with particular ones of the plurality of time offsets are grouped together in order to improve the efficiency of performing a fast Fourier transform of the data. In addition, the signal correlated with the generated frequency and the generated code having the plurality of time offsets may be a baseband signal that is a baseband representation of a received GPS signal.
Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention.
FIG. 1 illustrates a block diagram of a GPS receiver according to one embodiment of the present invention;
FIG. 2 illustrates a block diagram of correlation circuitry associated with a GPS receiver according to one embodiment of the present invention;
FIG. 3 illustrates a correlator associated with a GPS receiver according to one embodiment of the present invention;
FIG. 4 illustrates data from correlation circuitry during a two-dimensional search for a frequency and time offset of a received signal according to one embodiment of the present invention;
FIG. 5 illustrates the functionality of address translation logic associated with a GPS receiver according to one embodiment of the present invention;
FIG. 6 illustrates a GPS receiver incorporated in a wireless communications device according to one embodiment of the present invention;
FIG. 7 graphically illustrates the output of accumulation circuitry in response to detection of a jamming interference signal according to one embodiment of the present invention; and
FIG. 8 illustrates a clock and power management module controlling clock signals associated with exemplary domains of a GPS receiver according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.
The present invention is preferably incorporated in a GPS receiver 10 . The basic architecture of a GPS receiver 10 is represented in FIG. 1 and may include a receiver frontend 12 , an antenna 14 , and a digital application specific integrated circuit (ASIC) 16 . The receiver frontend 12 receives information previously modulated on a radio frequency carrier from one or more satellite vehicles through antenna 14 . The received signal is amplified, filtered, downconverted, and digitized by the receiver frontend 12 to produce a digital baseband signal representative of the received signal. The receiver frontend 12 also produces a clock (CLK) signal based on a signal from a local oscillator 17 . The frequency uncertainty of the local oscillator 17 is a major source of the frequency uncertainty of the received signal.
The digital ASIC 16 processes the digitized baseband signal to extract the information and data bits conveyed in the received signal. Correlation circuitry 18 communicates with a controller 20 to perform such operations as decimation, demodulation, correlation, and accumulation. The controller 20 is interfaced to memory 22 , which may include random-access memory (not shown) and read-only memory (not shown) and may alternatively be internal to the controller 20 . The memory 22 is used by the controller 20 to store GPS related information such as ephemeris data, almanac data, last known position, etc. Further, the memory 22 may store program instructions to be executed by the controller 20 .
The N parallel outputs from the correlation circuitry 18 are multiplexed by the multiplexer (MUX) 24 , which is controlled by a select signal (SEL) from the controller 20 , into a serial stream of data (DATA) and transferred to addresses in the memory 22 . The addresses where the data is stored are determined by using address translation logic (ATL) 26 to translate addresses from a direct memory access (DMA) controller 28 . Once the data is stored in the memory 22 , fast Fourier transform (FFT) circuitry 30 retrieves the data via the DMA controller 28 and produces transformed data, which is the result of the fast Fourier transform of the data. The result of the FFT process is stored in the memory 22 via the DMA controller 28 for use by the controller 20 . Additionally, the controller 20 is operatively connected to an input/output (I/O) subsystem 32 in order to communicate with external devices.
Jammer response circuitry 38 provides a control signal (CNTL) to the correlation circuitry 18 when a transmission from a nearby wireless communication device is detected. In another embodiment, the jammer response circuit 38 may be part of a wireless communication device, such as a mobile telephone, capable of asserting the control signal CNTL while transmitting. However, the jammer response circuit 38 may be any circuit or device that is capable of detecting a transmission of a jamming interference signal.
FIG. 2 illustrates the correlation circuitry 18 in more detail. The correlation circuitry 18 includes a number of correlators N having been divided into N/4 channels each having four correlators. As an example, a first channel 40 and a last channel 42 each have four correlators 44 , 46 , 48 and 50 and 52 , 54 , 56 and 58 , respectively. Each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 is capable of correlating the baseband signal from the receiver frontend 12 with a generated frequency (F) and a pseudo random noise code having a time offset (OFFSET I ) generated by the controller 20 , where I=0, 1, 2, . . . N−1. Further, each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 is controlled by the control signal CNTL from the jammer response circuit 38 such that the correlation process pauses during transmissions from the nearby wireless communication device. While only the first channel 40 and the last channel 42 are illustrated, it should be clear that the correlation circuitry 18 includes N/4 channels, each being essentially the same as the channels 40 and 42 described above.
A more detailed illustration of each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 is given in FIG. 3 . Each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 may include decimation circuitry 60 , carrier demodulation circuitry 62 , code correlation circuitry 64 , and accumulation circuitry 66 . The decimation circuitry 60 receives the baseband signal from the receiver frontend 12 and decimates a sample rate of the received signal to a decimated rate equal to or less than the sample rate. After decimation, the carrier demodulation circuitry 62 demodulates the decimated baseband signal using the generated frequency F from the controller 20 , thereby providing a demodulated baseband signal to the code correlation circuitry 64 .
The code correlation circuitry 64 correlates the demodulated baseband signal with the generated pseudo-random noise (PRN) code from the controller 20 having the time offset OFFSET I . Further, each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 may demodulate the decimated baseband signal using the same generated frequency F, but may correlate the demodulated baseband signal with the generated code having different time offsets OFFSET I . The output of the code correlation circuitry 64 is accumulated for an amount of time, which depends on the particular design of the GPS receiver 10 , and transferred to the memory 22 via the multiplexer 24 . In one embodiment, the amount of time the output of the code correlation circuitry 64 is accumulated is 32 μs, which is discussed in detail below. The accumulated output of the accumulation circuitry 66 is at a maximum when the frequency F and the time offset OFFSET I match the frequency and time offset of the baseband signal from the receiver frontend 12 .
Establishing the Frequency and Time Offset of GPS Signals
According to one embodiment, the GPS receiver 10 of the present invention is capable of concurrently searching an approximately 30,000 Hz range of frequencies for the baseband signal received from the receiver frontend 12 . Further, the GPS receiver 10 is capable of performing a two-dimensional search for both the frequency of the baseband signal and the time offset of the C/A code or the y-code carried in the received signal. For this example, the received signal includes up to twelve L 1 signals, the baseband signal is a baseband digital representation of the received signal, and the generated code from the controller 20 is the C/A code corresponding to a particular one of the L 1 signals. In addition, the number of correlators is 48 (N=48), thereby defining 12 (N/4) channels.
FIG. 4 illustrates a data set consisting of the data produced by the correlation circuitry 18 during the two-dimensional search performed by the digital ASIC 16 in the GPS receiver 10 . Each row is the output over time of one of the 48 correlators, examples of which are the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 . Each column is a partial correlation sample period S 0 . . . S M−1 . Additionally, the data elements DATA X,Y , or partial correlation samples, can be any number of bits, where the subscript X=0, 1, . . . N−1 corresponds to the time offset OFFSET I and the subscript Y=0, 1, . . . M−1 corresponds to the partial correlation sample periods S 0 , S 1 , . . . S M−1 and M is the number of points in the FFT operation.
In this example, each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 correlate the received signal with the generated frequency F and the generated PRN code having a different time offset OFFSET I for a total of 2 ms. However, the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 accumulate the results of the correlation and provide the data elements DATA X,Y , also called partial correlation samples, at 32 μs intervals, thereby defining the partial correlation sample periods. By producing 64 partial correlation samples at 32 μs intervals, the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 have effectively correlated the baseband signal with the generated frequency F and the generated PRN code having a different time offset OFFSET I for a total of 2 ms.
If each partial correlation sample DATA X,Y is a 32 μs accumulation of the results of the correlated data, 64 partial correlation samples may be processed by the FFT circuitry 30 by performing a 64-point FFT operation to accomplish a search over an approximately 30,000 Hz frequency range for each of the time offsets corresponding to each of the 48 correlators. The frequency separation, or bin width, of the results of the 64-point FFT operation is 1/(M×T), where M is the number of points in the FFT operation and T is equal to the partial correlation sample period. Therefore, the frequency separation of this 64-point FFT operation is approximately 500 Hz, and the frequency range covered by the operation is approximately 30,000 Hz (64×500 Hz=30,000 Hz). The frequency range covered by the FFT operation corresponds to the approximately 30,000 Hz range of frequencies containing the received signal. Although the two are not centered at the same frequency, the results of the FFT operation can be used to determine the location of the frequency of the received signal within the approximately 30,000 Hz range of frequencies.
In operation, the two-dimensional search begins when the controller 20 sets the generated frequency F to a nominal frequency associated with the baseband signal from the receiver frontend 12 and sends the generated code with offsets OFFSET 0 , OFFSET 1 . . . OFFSET 47 to the correlation circuitry 18 . It is to be understood that the controller 20 can set the generated frequency F to any of a plurality of frequencies. In addition, the controller 20 is capable of generating a different generated frequency F for each of the channels 40 and 42 .
Once, the generated frequency F and time offsets OFFSET I have been sent to the correlation circuitry 18 , the accumulation circuitry 66 of each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 accumulates the output of the code correlation circuitry 64 for a the partial correlation period S 0 of the C/A code, thereby producing the partial correlation samples DATA X,0 . In this example, the partial correlation period is approximately 32 μs or 33 C/A code chips. The accumulated outputs of partial correlation samples from the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 are serially transferred by the multiplexer 24 to the addresses in the memory 22 determined by the address translation logic 26 . This process is repeated 64 times for each of the partial correlation sample periods S 0 . . . S M−1 to produce the data set for the 64-point FFT operation performed by the FFT circuitry 30 . A total correlation period for the data set is 2 ms (32 μs×64).
After the partial correlation samples DATA X,Y have been stored for each of the partial correlation periods S 0 . . . S M−1 and the offsets OFFSET 0 . . . OFFSET 47 , the data is transferred to the FFT circuitry 30 from the memory 22 using the DMA controller 28 . The FFT circuitry 30 performs the 64-point FFT operation on the data from each of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 and transfers the results (FFT RESULTS) back to the memory 22 using the DMA controller 28 . This completes one iteration of the two-dimensional search, which has searched the approximately 30,000 Hz range of frequencies and the 48 time offsets. The controller may now determine if the received signal was present at any of the frequency/time/PRN combinations in the data set.
Several more iterations of the two-dimensional search can be performed to search each possible time offset of the 1023 chip C/A code. For example, if the C/A code is searched in ½ chip steps, 2046 time offsets will be searched. Each iteration searches 48 new time offsets until all time offsets have been searched. After each of the possible time offsets has been searched, the controller 20 can then determine the frequency F and time offset OFFSET I of the baseband signal from the receiver frontend 12 by processing the results from the FFT circuitry 30 for each iteration. The frequency F and time offset OFFSET I can be stored in the memory 22 to be accessed by the controller 20 .
Typically, the GPS receiver 10 will attempt the search for and acquire signals from more than one satellite, each having a different C/A code. Further, the C/A code (or PRN) of the received signals may not be known. Therefore, the GPS receiver 10 may perform more than one successive two-dimensional search. For each successive search, the two-dimensional search described above is repeated with controller 20 sending different generated codes corresponding to possible C/A codes associated with each of the received L 1 signals to the correlation circuitry 18 . Once the desired number of two-dimensional searches has been completed, each received L 1 signal is then tracked by the GPS receiver 10 using the channels, examples of which are the channels 40 and 42 , where each of the channels is capable of tracking one of the received L 1 signals.
Address Translation Logic (ATL)
If the data from only one of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 , and 58 were to be transferred to the FFT circuitry 30 , the data transfer could be fully automated with standard DMAs set up by the controller 20 . However, if the data is transferred from the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 in parallel and is multiplexed into the serial stream of data to be transferred to the memory 22 with the DMA controller 28 , the resulting data blocks will have interleaved data from all of the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 . Without the ATL 26 , the data would need to be re-grouped manually by the controller 20 , increasing the need for system throughput, or de-multiplexed into as many FFT modules as there are correlators. The address translation logic 26 allows the FFT of the data associated with the parallel correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 to be performed by the single FFT circuitry 30 rather than having numerous of FFT modules processing the data in parallel, or having the controller manually reorganize the data before it is processed by the FFT circuitry 30 . By doing so, the overall size of the GPS receiver 10 and the power consumed by the GPS receiver 10 is reduced.
The address translation logic 26 translates the addresses from the DMA controller 28 without intervention from the controller 20 such that consecutive data from each of the forty-eight correlators, examples of which are the correlators 44 , 46 , 48 , 50 , 52 , 54 , 56 and 58 , is stored in consecutive memory locations, as illustrated in FIG. 5 . By doing so, all of the data relating to a particular time offset OFFSET I are grouped together in the memory 22 , enabling efficient transfer to the FFT circuitry 30 . For example, the data elements, also referred to as the partial correlation samples, received consecutively from the correlation of the time offset OFFSET 0 are defined as DATA 0,0 , DATA 0,1 , DATA 0,2 . . . DATA 0,M−1 . The address translation logic 26 operates to store these data elements in consecutive locations in the memory 22 . Without the address translation logic 26 , the data from the correlation circuitry 18 would be stored in the order it is received by the memory 22 , which would require the controller 20 to reorganize the data before sending the data to the FFT circuitry 30 .
Using FIG. 5 as an example, the data elements DATA X,Y corresponds to the data from the accumulation of the correlation of the received signal with the PRN code having the time offset OFFSET I and the generated frequency F, where the subscript X corresponds to the time offset OFFSET I and the subscript Y corresponds to the partial correlation sample period. The data is transferred such that the data is grouped by the partial correlation sample period corresponding to the subscript Y, where Y=0, 1, 2, . . . M−1. For example, the partial correlation samples produced by the correlation of the received signal with the PRN code having each of the time offsets OFFSET I at the partial correlation sample period S 0 , DATA 0,0 , DATA 1,0 , DATA 2,0 , . . . DATA N−1,0 , are grouped together when received by the memory 22 . Using the translated address from the address translation logic 26 , the memory 22 stores the data transmitted serially from the multiplexer 24 such that the partial correlation samples are grouped by the time offset OFFSET I corresponding to the subscript X. For example, the partial correlation samples associated with the time offset OFFSET 0 corresponding to the subscript X, DATA 0,0 , DATA 0,1 , DATA 0,2 , . . . DATA 0,M−1 , are grouped together in the memory 22 .
Avoiding Interference to a GPS System from Wireless Transmissions
FIG. 6 is a simplified block diagram of the GPS receiver 10 being used in combination with a wireless communications device 68 , such as a mobile telephone. The wireless communications device 68 may include receive (RX) circuitry 70 , transmit (TX) circuitry 72 , and control and processing circuitry 74 . The receive circuitry 70 operates to receive the GPS signal and any communication signals. The transmit circuitry 72 operates to transmit communication signals from the wireless communications device 68 . The control and processing circuitry 74 operates to process the communications signals sent to the wireless communications device 68 and send communications data to the transmit circuitry 72 to be transmitted as the communications signals. The receive circuitry 70 and the transmit circuitry 72 are shown to use the antenna 14 , which is also used to receive the GPS signal. However, the receive circuitry 70 and the transmit circuitry 72 may use a separate antenna (not shown) to transmit and receive the communication signals.
When a jamming signal is strong enough, because of jammer output power and/or close proximity to a GPS receiver 10 , and close enough to the GPS L 1 or L 2 frequencies, it may pass through the receiver frontend 12 and into the digital ASIC 16 and particularly into the correlation circuitry 18 , where the jamming signal may be tracked as a valid GPS signal. This can cause the tracking loops (not shown) and navigation filters (not shown) of the correlation circuitry 18 and the controller 20 to malfunction, and because these functions incorporate relatively long time constant filters, it may take some time for the GPS receiver 10 to return to normal operation even after the jamming signal is removed.
The jammer response circuitry 38 detects, or is informed by the control and processing unit 74 , when the transmit circuitry 72 is transmitting the communication signals, which would be a jamming interference signal in the reception of the GPS signal. The communications signals are signals that are transmitted from the wireless communications device 68 under normal operating conditions. Therefore, by using the control signal CNTL from the jammer response circuitry 38 , the digital ASIC has the ability to pause the baseband processing of the very weak L 1 or L 2 signal, which is typically −133 dBm, while the much stronger communications signal is transmitted from the wireless communications device 68 . The control signal CNTL from the jammer response circuitry 38 allows the accumulation circuitry 66 in the digital ASIC 16 to pause accumulation during a transmission from the transmitter. By doing so, the GPS receiver 10 will only see a minimal performance degradation caused by the transmitted signals from the transmit circuitry 72 of the wireless communications device 68 . The GPS receiver 10 will also return to normal operation much faster once the transmit circuitry 72 of the wireless communications device 68 stops transmitting. This is because the only filters (energy storage elements) that experience the energy from the jamming interference signal are relatively wide bandwidth filters with time-constants of much less than 1 μs (1 C/A chip).
FIG. 7 illustrates the effect of the control signal CNTL from the jammer response circuitry 38 on the output of the accumulation circuitry 66 . As illustrated, the accumulation circuitry 66 temporarily stops accumulation when the control signal CNTL is asserted, thereby signifying a transmission of the jamming interference signal. Further, the output of the accumulation circuitry 66 is constant while the control signal CNTL is asserted. When the control signal CNTL signifies the end of the transmission, the accumulation circuitry 66 resumes accumulation. The ability to temporarily stop accumulation during the transmission of a jamming interference signal allows the GPS receiver 10 to maintain system performance while experiencing only a minimal drop in the signal-to-noise ratio.
Saving Power by Controlling Domain Clocking
According to one embodiment, the controller 20 includes a clock and power management (CPM) module 76 as illustrated in FIG. 8 . The clock and power management module 76 allows the controller 20 to control the power consumption of the digital ASIC 16 by controlling the clock signals used to clock the digital ASIC 16 . As an example, the digital ASIC 16 can be divided into twelve channel domains, examples of which are a channel 1 domain 78 and a channel 12 domain 80 , an integrated phase modulator (IPM) domain 82 , a data collect domain 84 , an events domain 86 , a user time logic domain 88 , a receiver circuitry domain 90 , and a FFT domain 92 being clocked by clock signals CLK 1 . . . CLK 12 , CLK 13 , CLK 14 , CLK 15 , CLK 16 , CLK 17 , and CLK 18 , respectively. Preferably, each of the domains 78 , 80 , 82 , 84 , 86 , 88 , 90 , and 92 implements complementary metal-oxide-silicon (CMOS) or similar logic such that power consumption ceases when the logic is not clocked.
The channel domains 78 and 80 include circuitry associated with the channels 40 and 42 and can be powered down when not in use by deactivating the clock signals CLK 1 and CLK 12 , respectively. The IPM domain 82 includes circuitry used by the controller 20 to produce the frequency F and the code having the time OFFSET I and can be powered down by deactivating the clock signal CLK 13 . The data collect domain 84 includes circuitry for deriving a noise floor used by the controller 20 to determine a relative magnitude of the data from the correlation circuitry 18 with respect to noise received by the receiver 10 , and can be powered down by deactivating the clock signal CLK 14 . The events domain 86 includes logic used to time stamp input or output data received from or sent to the I/O subsystem 32 , and can be powered down by deactivating the clock signal CLK 15 . The user time logic domain 88 includes logic used to keep a local clock (not shown) that is continuously corrected using the received GPS signals, and can be powered down by deactivating the clock signal CLK 16 . The receiver circuitry domain 90 includes circuitry not included in the other domains such as the controller 20 , the address translation logic 26 , and the DMA controller 28 , and can be powered down by deactivating the clock signal CLK 17 . The FFT domain 92 includes the FFT circuitry 30 and can be powered down by deactivating the clock signal CLK 18 .
The receiver 10 and in particular the digital ASIC 16 of the present invention offer substantial opportunity for variation without departing from the spirit and scope of the invention. For example, the number of correlators N has been shown to be 48 as an example. However, the number N could be any number between 1 and 2046. As another example, the frequency range covered by the 64-point FFT operation is shown to be the approximately 30,000 Hz, but the frequency range could be any range sufficient to overcome errors caused by Doppler and local oscillator imperfections. Further, the number of points in the FFT operation M used to cover the approximately 30,000 Hz range of frequencies could vary depending on particular design requirements. As yet another example, the digital ASIC 16 could be divided into any number of domains, which can be powered down by deactivating the clock signals to the domains.
The foregoing details should, in all respects, be considered as exemplary rather than as limiting. The present invention allows significant flexibility in terms of implementation and operation. Examples of such variation are discussed in some detail above; however, such examples should not be construed as limiting the range of variations falling within the scope of the present invention. The scope of the present invention is limited only by the claims appended hereto, and all embodiments falling within the meaning and equivalency of those claims are embraced herein.
Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow. | The address translation logic of the present invention is incorporated in a global positioning system (GPS) receiver and operates to group data in memory based on translating the address from a direct memory access controller. The data includes post-correlated samples of the correlation of a signal with a generated frequency and a generated code having a plurality of time offsets. In general, the address translation logic organizes the data such that each element of the data associated with particular ones of the plurality of time offsets are grouped together in order to improve the efficiency of performing a fast Fourier transform of the data. In addition, the address translation logic allows the transfer of data from correlation circuitry to memory, from the memory to an FFT module, and from the FFT module to the memory using standard DMA controllers. | 6 |
PRIORITY AND CROSS REFERENCES
This patent application claims the priority from PCT/IB2012/052490 filed on 17 May 2012 which claims priority from Italian Patent Application Number TO2011A000441 filed on 18 May 2011, the teachings of both of which are incorporated in their entirety.
BACKGROUND
It is known in the processing of ligno-cellulosic biomass to pretreat the biomass prior to hydrolysis or fermentation. This pre-treatment can be in the form of soaking the ligno-cellulosic biomass and separating the water soluble (C5) species in the liquid stream from the solids, and steam exploding the solid stream, or just steam exploding the ligno-cellulosic biomass stream.
Because the pre-treatments are aggressive, they create by-products such as acetic acid and furfural. A large amount of effort has been spent on trying to remove the acetic acid and/or furfural after pre-treatment as these chemicals inhibit and suppress further processing such as fermentation.
To date, no one has successfully managed to remove the acetic acid from a pre-treated stream of ligno-cellulosic biomass.
SUMMARY
This specification discloses a process for the removal of acetic acid from a pre-treated ligno-cellulosic biomass, which is a process for treating a ligno-cellulosic biomass feed stream comprised of solids, C5's, C6's, lignin, and water, comprising the steps of
A) Pretreating the ligno-cellulosic biomass feed stream by contacting the ligno-cellulosic biomass with water in the temperature range of 40 to 210° C. to create a pre-treated ligno-cellulosic biomass comprised of a pre-treatment ligno-cellulosic biomass liquid comprised of suspended solids, C5's, C6's, and acetic acid, wherein the ratio of the C6's to C5's is less than 0.8 to 1.0, and a pre-treated ligno-cellulosic biomass solids, B) Separating at least a portion of the pre-treatment ligno cellulosic biomass liquid from the pre-treated ligno-cellulosic biomass feed stream, C) Separating at least a portion of the suspended solids from the pre-treatment ligno-cellulosic biomass liquid using filters, centrifuge or combination thereof, to create a clarified liquid stream, D) Nano filtering at least a portion of the clarified liquid stream to create a nano-filtered permeate stream comprised of acetic acid and water and a nano-filtered retentate stream comprised of C5's, C6's, acetic acid and water, wherein the ratio of acetic acid to the total amount of C5's, C6's in the clarified liquid stream is greater than the ratio of the acetic acid to the total amount of C5's, C6's in the nano-filtered retentate.
It is further disclosed that the nano-filtered permeate stream can be dewatered by reverse osmosis to create a reverse osmosis permeate comprised of water and reverse osmosis retentate comprised of water and acetic acid.
It is also further disclosed that the reverse osmosis permeate may be further used in a hydrolysis process or reused in the pre-treatment process and that the acetic acid of the reverse osmosis retenate is further used in a hydrolysis process.
It is also disclosed that the ligno-cellulosic biomass feedstream has not been steam exploded.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic representation of the embodied process.
DETAILED DESCRIPTION
This specification discloses a process to remove the acetic acid from a pre-treated ligno-cellulosic biomass stream.
The pretreated biomass usually comes from a lignocellulosic biomass or lignocellulosic compounds which has been pretreated by means of a process where the biomass, chosen as a preferred feedstock that is usually a plant biomass with cellulose, hemicelluloses and lignin, is soaked with water and maintained for a certain time at a certain temperature to obtain the pretreated biomass with a dry content and a water portion.
Because the feedstock may use naturally occurring ligno-cellulosic biomass, the stream will have relatively young carbon materials. The following, taken from ASTM D 6866-04 describes the contemporary carbon, which is that found in bio-based hydrocarbons, as opposed to hydrocarbons derived from oil wells, which was derived from biomass thousands of years ago. “[A] direct indication of the relative contribution of fossil carbon and living biospheric carbon can be as expressed as the fraction (or percentage) of contemporary carbon, symbol f C . This is derived from f M through the use of the observed input function for atmospheric 14 C over recent decades, representing the combined effects of fossil dilution of the 14 C (minor) and nuclear testing enhancement (major). The relation between f C and f M is necessarily a function of time. By 1985, when the particulate sampling discussed in the cited reference [of ASTM D 6866-04, the teachings of which are incorporated by reference in their entirety] the f M ratio had decreased to ca. 1.2.”
Fossil carbon is carbon that contains essentially no radiocarbon because its age is very much greater than the 5730 year half life of 14 C. Modern carbon is explicitly 0.95 times the specific activity of SRM 4990b (the original oxalic acid radiocarbon standard), normalized to
δ 13 C=−19%. Functionally, the faction of modern carbon=(1/0.95) where the unit 1 is defined as the concentration of 14 C contemporaneous with 1950 [A.D.] wood (that is, pre-atmospheric nuclear testing) and 0.95 are used to correct for the post 1950 [A.D.] bomb 14 C injection into the atmosphere. As described in the analysis and interpretation section of the test method, a 100% 14 C indicates an entirely modern carbon source, such as the products derived from this process. Therefore, the percent 14 C of the product stream from the process will be at least 75%, with 85% more preferred, 95% even preferred and at least 99% even more preferred and at least 100% the most preferred. (The test method notes that the percent 14 C can be slightly greater than 100% for the reasons set forth in the method). These percentages can also be equated to the amount of contemporary carbon as well.
Therefore the amount of contemporary carbon relative to the total amount of carbon is preferred to be at least 75%, with 85% more preferred, 95% even more preferred and at least 99% even more preferred and at least 100% the most preferred. Correspondingly, each carbon containing compound in the reactor, which includes a plurality of carbon containing conversion products will have an amount of contemporary carbon relative to total amount of carbon is preferred to be at least 75%, with 85% more preferred, 95% even preferred and at least 99% even more preferred and at least 100% the most preferred.
In general, a natural or naturally occurring ligno-cellulosic biomass can be one feed stock for this process. Ligno-cellulosic materials can be described as follows:
Apart from starch, the three major constituents in plant biomass are cellulose, hemicellulose and lignin, which are commonly referred to by the generic term lignocellulose. Polysaccharide-containing biomasses as a generic term include both starch and ligno-cellulosic biomasses. Therefore, some types of feedstocks can be plant biomass, polysaccharide containing biomass, and ligno-cellulosic biomass.
Polysaccharide-containing biomasses according to the present invention include any material containing polymeric sugars e.g. in the form of starch as well as refined starch, cellulose and hemicellulose.
Relevant types of naturally occurring biomasses for deriving the claimed invention may include biomasses derived from agricultural crops selected from the group consisting of starch containing grains, refined starch; corn stover, bagasse, straw e.g. from rice, wheat, rye, oat, barley, rape, sorghum; softwood e.g. Pinus sylvestris, Pinus radiate ; hardwood e.g. Salix spp. Eucalyptus spp.; tubers e.g. beet, potato; cereals from e.g. rice, wheat, rye, oat, barley, rape, sorghum and corn; waste paper, fiber fractions from biogas processing, manure, residues from oil palm processing, municipal solid waste or the like. Although the experiments are limited to a few examples of the enumerated list above, the invention is believed applicable to all because the characterization is primarily to the unique characteristics of the lignin and surface area.
The ligno-cellulosic biomass feedstock used to derive the composition is preferably from the family usually called grasses. The proper name is the family known as Poaceae or Gramineae in the Class Liliopsida (the monocots) of the flowering plants. Plants of this family are usually called grasses, or, to distinguish them from other graminoids, true grasses. Bamboo is also included. There are about 600 genera and some 9,000-10,000 or more species of grasses (Kew Index of World Grass Species).
Poaceae includes the staple food grains and cereal crops grown around the world, lawn and forage grasses, and bamboo. Poaceae generally have hollow stems called culms, which are plugged (solid) at intervals called nodes, the points along the culm at which leaves arise. Grass leaves are usually alternate, distichous (in one plane) or rarely spiral, and parallel-veined. Each leaf is differentiated into a lower sheath which hugs the stem for a distance and a blade with margins usually entire. The leaf blades of many grasses are hardened with silica phytoliths, which helps discourage grazing animals. In some grasses (such as sword grass) this makes the edges of the grass blades sharp enough to cut human skin. A membranous appendage or fringe of hairs, called the ligule, lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath.
Grass blades grow at the base of the blade and not from elongated stem tips. This low growth point evolved in response to grazing animals and allows grasses to be grazed or mown regularly without severe damage to the plant.
Flowers of Poaceae are characteristically arranged in spikelets, each spikelet having one or more florets (the spikelets are further grouped into panicles or spikes). A spikelet consists of two (or sometimes fewer) bracts at the base, called glumes, followed by one or more florets. A floret consists of the flower surrounded by two bracts called the lemma (the external one) and the palea (the internal). The flowers are usually hermaphroditic (maize, monoecious, is an exception) and pollination is almost always anemophilous. The perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea; these are generally interpreted to be modified sepals.
The fruit of Poaceae is a caryopsis in which the seed coat is fused to the fruit wall and thus, not separable from it (as in a maize kernel).
There are three general classifications of growth habit present in grasses; bunch-type (also called caespitose), stoloniferous and rhizomatous.
The success of the grasses lies in part in their morphology and growth processes, and in part in their physiological diversity. Most of the grasses divide into two physiological groups, using the C3 and C4 photosynthetic pathways for carbon fixation. The C4 grasses have a photosynthetic pathway linked to specialized Kranz leaf anatomy that particularly adapts them to hot climates and an atmosphere low in carbon dioxide.
C3 grasses are referred to as “cool season grasses” while C4 plants are considered “warm season grasses”. Grasses may be either annual or perennial. Examples of annual cool season are wheat, rye, annual bluegrass (annual meadowgrass, Poa annua and oat). Examples of perennial cool season are orchard grass (cocksfoot, Dactylis glomerata ), fescue ( Festuca spp), Kentucky Bluegrass and perennial ryegrass ( Lolium perenne ). Examples of annual warm season are corn, sudangrass and pearl millet. Examples of Perennial Warm Season are big bluestem, indiangrass, bermuda grass and switch grass.
One classification of the grass family recognizes twelve subfamilies: These are 1) anomochlooideae, a small lineage of broad-leaved grasses that includes two genera ( Anomochloa, Streptochaeta ); 2) Pharoideae, a small lineage of grasses that includes three genera, including Pharus and Leptaspis ; 3) Puelioideae a small lineage that includes the African genus Puelia ; 4) Pooideae which includes wheat, barley, oats, brome-grass ( Bronnus ) and reed-grasses ( Calamagrostis ); 5) Bambusoideae which includes bamboo; 6) Ehrhartoideae, which includes rice, and wild rice; 7) Arundinoideae, which includes the giant reed and common reed; 8) Centothecoideae, a small subfamily of 11 genera that is sometimes included in Panicoideae; 9) Chloridoideae including the lovegrasses ( Eragrostis , ca. 350 species, including teff), dropseeds ( Sporobolus , some 160 species), finger millet ( Eleusine coracana (L.) Gaertn.), and the muhly grasses ( Muhlenbergia , ca. 175 species); 10) Panicoideae including panic grass, maize, sorghum, sugar cane, most millets, fonio and bluestem grasses; 11) Micrairoideae and 12) Danthoniodieae including pampas grass; with Poa which is a genus of about 500 species of grasses, native to the temperate regions of both hemispheres.
Agricultural grasses grown for their edible seeds are called cereals. Three common cereals are rice, wheat and maize (corn). Of all crops, 70% are grasses.
Sugarcane is the major source of sugar production. Grasses are used for construction. Scaffolding made from bamboo is able to withstand typhoon force winds that would break steel scaffolding. Larger bamboos and Arundo donax have stout culms that can be used in a manner similar to timber, and grass roots stabilize the sod of sod houses. Arundo is used to make reeds for woodwind instruments, and bamboo is used for innumerable implements.
Another naturally occurring ligno-cellulosic biomass feedstock may be woody plants or woods. A woody plant is a plant that uses wood as its structural tissue. These are typically perennial plants whose stems and larger roots are reinforced with wood produced adjacent to the vascular tissues. The main stem, larger branches, and roots of these plants are usually covered by a layer of thickened bark. Woody plants are usually either trees, shrubs, or lianas. Wood is a structural cellular adaptation that allows woody plants to grow from above ground stems year after year, thus making some woody plants the largest and tallest plants.
These plants need a vascular system to move water and nutrients from the roots to the leaves (xylem) and to move sugars from the leaves to the rest of the plant (phloem). There are two kinds of xylem: primary that is formed during primary growth from procambium and secondary xylem that is formed during secondary growth from vascular cambium.
What is usually called “wood” is the secondary xylem of such plants.
The two main groups in which secondary xylem can be found are:
1) conifers (Coniferae): there are some six hundred species of conifers. All species have secondary xylem, which is relatively uniform in structure throughout this group. Many conifers become tall trees: the secondary xylem of such trees is marketed as softwood. 2) angiosperms (Angiospermae): there are some quarter of a million to four hundred thousand species of angiosperms. Within this group secondary xylem has not been found in the monocots (e.g. Poaceae). Many non-monocot angiosperms become trees, and the secondary xylem of these is marketed as hardwood.
The term softwood is used to describe wood from trees that belong to gymnosperms. The gymnosperms are plants with naked seeds not enclosed in an ovary. These seed “fruits” are considered more primitive than hardwoods. Softwood trees are usually evergreen, bear cones, and have needles or scale like leaves. They include conifer species e.g. pine, spruces, firs, and cedars. Wood hardness varies among the conifer species.
The term hardwood is used to describe wood from trees that belong to the angiosperm family. Angiosperms are plants with ovules enclosed for protection in an ovary. When fertilized, these ovules develop into seeds. The hardwood trees are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. These leaves can be either simple (single blades) or they can be compound with leaflets attached to a leaf stem. Although variable in shape all hardwood leaves have a distinct network of fine veins. The hardwood plants include e.g. Aspen, Birch, Cherry, Maple, Oak and Teak.
Therefore a preferred naturally occurring ligno-cellulosic biomass may be selected from the group consisting of the grasses and woods. Another preferred naturally occurring ligno-cellulosic biomass can be selected from the group consisting of the plants belonging to the conifers, angiosperms, Poaceae and families. Another preferred naturally occurring ligno-cellulosic biomass may be that biomass having at least 10% by weight of it dry matter as cellulose, or more preferably at least 5% by weight of its dry matter as cellulose.
The carbohydrate(s) comprising the invention is selected from the group of carbohydrates based upon the glucose, xylose, and mannose monomers and mixtures thereof.
The water of the feedstock is usually present in the form of water absorbed into the biomass itself and in the form of free water. The term biomass and water means the dry content of the biomass plus all the water which includes the water present prior to pre-treatment and the adsorbed water and the free water which have been added during the pretreatment process.
The pre-treated biomass can be characterized on the basis of its water, C5, C6, acetic acid, formic acid and furfural. The total C5's of the composition is the sum of arabinan and xylan in the composition which includes the monomers, dimers, oligomers and polymers of arabinose and xylose in the liquid and solid of the composition. The total C6's in the composition is the glucan content which includes the monomers, dimers, oligomers and polymers of glucose that may be present in the liquid and solids of the streams.
The pretreated biomass stream undergoes a separation step where the pretreated liquid biomass stream is separated in liquid form from the pretreated biomass using filter(s), centrifuge(s), press(es) or membrane or any other procedure able to separate a liquid stream from solids. The pre-treated liquid biomass stream should have a ratio by weight of total C6's to total C5's of less than 0.8 to 1.0, with less than 0.5 to 1.0 more preferred, less than 0.25 to 1 even more preferred, less than 0.1 to 1.0 even more preferred, and 0 to 1.0 being the most preferred. This is an example of a pretreated biomass liquid stream.
During the pretreatment step other organic compounds are usually formed or extracted from the biomass. These compounds usually derive from the cellulose or from the hemicellulose or from the lignin portions. In some cases, other organic compounds are present in the pretreated biomass stream due to organic compounds like starch or extractives in the inlet biomass feedstock to the pretreated process. These organic compounds, such as furfural, formic acid, and acetic acid, or at least a portion of them can be separated and collected in the pretreated biomass liquid stream.
The process described below has been able to remove one or more organic compounds of interest like the acetic acid from the pretreated liquid biomass stream.
One pre-treated stream of interest is the liquid stream obtained by water soaking the ligno-cellulosic biomass stream and removing the liquid. This stream will comprise water, some solids, acetic acid, and water soluble C5's as described above.
The pre-treated liquid ligno-cellulosic biomass stream comprising water, solids, acetic acid and C5's first undergoes a solids separation step. While any solid separation step is believed to work, it must be efficient enough to remove the solids that would otherwise destroy the membrane filtration process downstream. The preferred separation was done by centrifugation. After centrifugation, the liquid stream is nano-filtered. The centrifugation was done on an Alfa Laval Model LAB102B, with an operating velocity of 8800 rpm, having a volume of 0.1 liter and a maximum cake volume of 0.2 liter. The tests were operated between 50 and 100 liter/h with the best separation occurring in the range of 50-75 liter/h in which the suspended solids were reduced from 1.5% volume to 0% volume. Operating at higher than 75 liter/h left traces of suspended solids in the clarified liquid.
The nanofiltration step was conducted by passing the centrifuged stream over a membrane of polyamide type thin film composite on polyester having a MgSO4 rejection of 99%. This membrane is available from Alfa-Laval under the designation of NF99HF. The centrifuged stream should have a pH in the range of 2-10, and the nanofiltration conducted under a pressure in the range of about 1-55 bar and a temperature in the range of about 0-50° C. Two streams are created, a permeate stream and a retentate stream. In this specification, the permeate of the nano-filtration step is called the nano-filtered permeate stream and is comprised primarily of acetic acid and water. The material which does not pass through, or permeate, the membrane is called the retentate and is referred to as the nano-filtered retentate. Because the acetic acid and water pass through the membrane, the concentration of the acetic acid in the nano-filtered permeate stream is greater than the acetic concentration in the nano-filtered retentate stream.
The nano-filtered permeate stream comprised primarily of water and acetic acid was then subjected to reverse osmosis to separate substantially pure water from the permeate nano-filtered stream. The reverse osmosis occurs over a member thinfilm composite on polypropylene support paper having a NaCl rejection of greater than 96%. This type of membrane is available from Alfa-Laval under the designation of RO98pHt. The pH of the nano-filtered permeate stream during reverse osmosis is preferably in the range of 2-11, with the reverse osmosis preferably occurring under a pressure in the range of about 1-60 bar and a temperature preferably in the range of about 0-60° C.
The reverse osmosis permeate will be comprised almost entirely of water with the acetic acid concentration of the reverse osmosis retentate being greater than the acetic acid concentration of the reverse osmosis permeate.
The water of the reverse osmosis permeate can then be recycled back into the process, which for a second generation biomass facility is preferably the hydrolysis step.
FIG. 1 shows a typical unit operation process as described. The liquid stream feeds the process at 0.29 tonnes/h of acetic acid. After nano-filtration, the nano-filtered permeate has 0.2 ton per hour acetic acid, and after reverse osmosis, the reverse osmosis permeate has 0 tonnes of acetic per hour which is passed onto the viscosity reduction feeder. As the nano-filtered retentate will have some acetic acid (0.08 tonnes/hour), that is the only amount passed onto the hydrolysis/fermentation step. Thus, in this single step nano-filtration process, approximately 75% of the acetic acid was removed.
The nano-filtered retentate could be further filtered by either nano-filtration or reverse osmosis to further remove the remaining acetic acid.
While the above examples are exemplary of the invention, variants exist which are within the scope of inventor's invention as set forth in the claims.
EXPERIMENTAL
The following experiment evidences the different aspects of the disclosed invention.
FIG. 1 reports a diagram showing the experimental procedure and the flows obtained in the experiment.
Raw material (wheat straw) was introduced in a continuous reactor and subjected to soaking treatment at a temperature of 155° C. for 65 minutes. The soaked mixture was separated by means of a press in a liquid stream and a soaked stream containing the soaked solid raw material. The fraction containing the solid soaked raw material was subjected to steam explosion at a temperature of 190° C. for a time of 4 minutes to produce a steam exploded stream.
The liquid from the soaking comprised of suspended and unsuspended solids was subjected to a solid separation step to remove solids, by means of centrifugation and micro-filtration (bag filter with filter size of 1 micron). Centrifugation was performed by means of a Alfa Laval CLARA 80 centrifuge at 8000 rpm. A clarified liquid was separated from suspended solids.
The clarified liquid was then subjected to a first nano-filtration step by means of a Alfa Laval 3.8″ equipment (membrane code NF3838/48), according to the following procedure.
Permeate flow stability was checked by means of flushing with de-mineralized water, at the temperature of 50° C. and 10 bar. The flow rate of the permeate was measured. An amount of 1800 liter of clarified liquid were inserted in the feed tank. Before filtration, the system was flushed for 5 minutes, without pressure, in order to remove the water. The system was set at the operating conditions (pressure: 20 bar, temperature: 45° C.). The retentate stream was recycled to the feed tank and the permeate stream was dumped. The test was run until the volume of liquid in the feed tank was reduced up to 50% of the initial soaked liquid volume, corresponding to 900 liters of permeate and 900 liters of retentate. The previous procedure produced a first nano-filtered retentate NF1-R and a first nano-filtered permeated NF1-P.
The first retentate liquid NF1-R was diluted by adding a volume of water corresponding to 50% of volume of NF1-R. The diluted NF1-R, indicated as inlet NF2, was subjected to a second first nano-filtration step, according to the same procedure used in the first nano-filtration step. In this case, an amount of 1350 liter of inlet NF2 was inserted in the feed tank and the test was run until the volume of liquid in the feed tank was reduced up to 40.0% of the initial soaked liquid volume, corresponding to 540 liters of permeate and 810 liters of retentate.
The second nano-filtration produced a second nano-filtered retentate NF2-R and a second nano-filtered permeated NF2-P.
Nano-filtered permeates NF1-P and NF2-P were mixed to form inlet RO liquid, which was subjected to reverse osmosis by means of a Alfa Laval 2.5″ equipment (membrane code RO98pHt), according to the following procedure.
Permeate flow stability was checked by means of flushing with de-mineralized water, at room temperature (25° C.) and 10 bar. The flow rate of the permeate was measured. An amount of 192 liter of inlet RO liquid was inserted in the feed tank. Liquid pH was adjusted to 6 with a KOH diluted solution. Before filtration, the system was flushed for 5 minutes, without pressure, in order to remove the water. The system was set at the operating conditions (pressure: 30 bar, temperature: 50° C.). The retentate stream was recycled to the feed tank and the permeate stream was dumped. The test was run until the volume of liquid in the feed tank was reduced up to 33.3% of the initial pre-nano-filtrated liquid volume, corresponding to 128 liters of permeate and 64 liters of retentate.
The reverse osmosis produced a retentate RO and a permeate RO.
Suspended solids, steam exploded stream, permeate RO and retentate NF2-R were mixed to form the hydrolysis inlet.
Table 1 presents the concentrations of sugars and acetic acid in the flows marked 1 to 14 in FIG. 1 . Sugars are monomeric and oligomeric sugars which were solubilized.
According to the disclosed invention, the acetic acid to sugar ratio in NF-2R is lower than the ratio in clarified liquid.
The table presents also the flows relative to a continuous process, extrapolated from the experimental data, for a clarified liquid flow of 50 t/h.
TABLE 1
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
stream
clarified
retentate
per-
dilution
inlet
retentate
per-
inlet
retentate
per-
steam
suspended
dilution
hydro-
liquid
NF1-R
meate
water
NF2
NF2-R
meate
RO
RO
meate
exploded
solids
water
lysis
NF1-P
NF2-P
RO
stream
inlet
total mass
50.0
24.9
25.0
12.5
37.4
8.9
22.4
47.4
10.5
31.6
23.3
1.2
13.7
47.0
flow (t/h)
liquid
50.0
24.9
25.0
12.5
37.4
8.9
22.4
47.4
10.5
31.6
14.0
1.0
13.7
37.6
mass
flow (t/h)
sugars
1.28
1.21
0.00
1.21
1.15
0.00
0.00
0.00
0.00
0.07
0.03
1.2
flow
(t/h)
acetic acid
0.13
0.07
0.06
0.07
0.03
0.04
0.09
0.09
0.00
0.00
0.00
0.0
flow (t/h)
sugars
25.5
48.6
0.0
32.4
129.1
0.0
0.0
0.0
0.0
5.0
25.5
26.5
concen-
tration
(g\l)
acetic acid
2.5
2.8
2.3
1.8
3.5
1.7
2.0
8.9
0.0
0.2
2.5
0.8
concen-
tration
(g\l)
acetic
0.10
0.06
0.06
0.03
0.03
acid/
sugars
ratio | The process for treating a ligno-cellulosic biomass feed stream comprised of solids, C5's, C6's, lignin, and water comprises the steps of:
pretreating the ligno-cellulosic biomass feed stream by contacting the ligno-cellulosic biomass with water in the temperature range of 40 to 210° C. to create a pre-treated ligno-cellulosic biomass comprised of a pre-treatment ligno-cellulosic biomass liquid comprised of suspended solids, C5's, C6's, and acetic acid, wherein the ratio of the C6's to C5's is less than 0.8 to 1.0, and a pre-treated ligno-cellulosic biomass solids; separating a portion of the pre-treatment ligno cellulosic biomass liquid from the pre-treated ligno-cellulosic biomass feed stream; separating a portion of the suspended solids from the pre-treatment ligno-cellulosic biomass liquid using filters, centrifuge or combination thereof, to create a clarified liquid stream, and nano filtering a portion of the clarified liquid stream to create a nano-filtered permeate stream comprised of acetic acid and water and a nano-filtered retentate stream comprised of C5's, C6's, acetic acid and water, wherein the ratio of acetic acid to the total amount of C5's, C6's in the clarified liquid stream is greater than the ratio of the acetic acid to the total amount of C5's, C6's in the nano-filtered retentate. | 8 |
BACKGROUND OF THE INVENTION
This invention relates generally to magnetic resonance imaging equipment, and more particularly to a method for reducing transient noise that interferes with the desired signal and may decrease the quality of the image that is produced.
Magnetic resonance imaging, or “MRI,” is an excellent medical diagnostic tool that has been around for several decades. The details of MRI are well-known and need not be repeated herein. In general, MRI involves placing a subject, such as a person, in a magnetic field of known strength. The hydrogen atoms in the subject, which are typically the atoms that are used for imaging in current MRI machines, will have a resonant frequency that is directly proportional to the applied magnetic field. By “shaping” the static magnetic field through the use of gradient coils, it is possible to produce a static magnetic field of known quantity at a single isolated region within the subject. This region is generally referred to as a voxel, and may be on the order of one cubic millimeter. By imaging thousands of these individual voxels, an overall image of the subject can be recreated.
The imaging of an individual voxel involves applying a radio frequency to the subject that corresponds to the resonant frequency of the voxel undergoing imaging. This resonant frequency is also known as the Larmor frequency. A certain number of hydrogen atoms in the voxel being imaged will absorb energy from the radio signal, which will cause them to switch spin states from a low energy state to a high energy state. After the radio signal is terminated, a certain number of hydrogen atoms in the high energy state will relax back to the low energy state, giving off a signal of known frequency during this relaxation process. By detecting this emitted signal, it is possible to determine the relative hydrogen content of the voxel being imaged. If the subject being imaged is a human, the different concentrations of hydrogen in the different human tissues will produce different signals for the voxels of different tissues. The different signals allow an image to be reconstructed such that it corresponds to the different tissues in the human body.
The signal emitted by the hydrogen atoms when relaxing from a high energy state to a low energy state is detected by a receiving antenna or coil that is positioned around the subject being imaged. In the case of MRI's designed for imaging humans, the receiving antenna or coil is generally cylindrically shaped with the person positioned in the center of the cylinder. The MRI machine may contain a number of different coils of different size, location, and configuration in order to image different parts of the human body. In addition to the signals emitted by the relaxing hydrogen atoms, the detector coils or antennas will sense additional noise or interference signals. These noise or interference signals are desirably removed from the detected signal in order to produce a better image.
One prior art method for reducing the noise or interference in the receiving antennas is disclosed in U.S. Pat. No. 5,525,906 issued to Crawford et al., the disclosure of which is hereby incorporated herein by reference. In this method, which is depicted in block diagram in FIG. 3 herein, the signal from the receiving antenna is split into a detect path signal 1020 and a receive path signal 1022 . The detect path 1020 passes through a band pass filter 1024 which removes broad band thermal noise from the detect path signal 1020 . The detect path signal 1020 then passes through an amplifier 1026 before being input into a notch or band reject filter 1028 . Notch filter 1028 is designed to reject all frequencies that occur within the desired signal frequency range, which has a known bandwidth. The output 1030 of filter 1028 will thus consist of unfiltered noise. The unfiltered noise 1030 is input into a comparator 1032 which compares this signal to a voltage threshold 1034 . If the unfiltered noise signal 1030 exceeds the voltage threshold 1034 , comparator 1032 outputs a signal at 1036 that causes switch SW 1 to open, thereby blanking the output 1038 . If the unfiltered noise signal 1030 does not exceed the voltage threshold 1034 , the comparator outputs signal 1036 , which leaves switch SW 1 closed such that the receive signal 1022 is passed through to output 1038 , after passing through delay filter 1040 . The purpose of delay filter 1040 is to delay the signal on the receive path 1022 from reaching switch SW 1 prior to comparator output signal 1036 reaching switch SW 1 . Such a system is described in more detail in the U.S. Pat. No. 5,525,906, particularly in reference to FIGS. 3 and 4 in the corresponding disclosure therein. While this prior art method has been successful in producing images of higher clarity, the need still exists for improved imaging techniques.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an improved method and apparatus for increasing the quality of MRI images. The present invention achieves this improved quality by providing an improved method for detecting transient noise that is generated in the MRI system.
According to one embodiment of the present invention, a method is provided for detecting interference in an MRI signal received from an MRI receiving antenna. The method comprises detecting a parameter of the MRI signal that varies as the envelope of the MRI signal varies and filtering the MRI signal to thereby produce a filtered parameter signal. The filtered parameter signal is them compared to a reference signal. The MRI signal is determined to likely include interference if the filtered parameter signal exceeds the reference signal.
According to another aspect of the invention, a method is provided for detecting transient interference in an MRI signal that comprises detecting an envelope of the MRI signal and filtering out low frequency components of the MRI signal to thereby produce a filtered envelope signal. The filtered envelope signal is compared to a reference signal and it is determined that the MRI signal includes interference if the filtered envelope signal exceeds the reference signal.
According to still another aspect of the invention, an interference detection system is provided for detecting interference in an MRI signal received from an MRI receiving antenna. The system includes a filter designed to remove low frequency components within the MRI signal, and an envelope detector that detects the envelope of the MRI signal. The filter and envelope detector produce in combination a filtered envelope signal. A comparator compares the filtered envelope signal to a reference signal and outputs an interference signal if the filtered envelope signal exceeds the reference signal.
According to yet another aspect of the invention, an interference detection system is provided for detecting interference in an MRI signal received from an MRI receiving antenna. The system comprises a filter designed to remove low frequencies within the MRI signal and a detector that detects a parameter that varies as the envelope of the MRI signal varies. The filter and detector produce in combination a filtered parameter signal. A comparator compares the filtered parameter signal to a reference signal and outputs an interference signal if said filtered parameter exceeds the reference signal.
In still other aspects of the invention, the parameter detector and/or the envelope detector may comprises a detector log video amplifier. The system may include a blanking switch controlled in a manner to blank the MRI signal if the comparator outputs the interference signal. The system may further includes a retriggerable multivibrator that is activated by the interference signal.
The methods and systems of the present invention provide improved clarity in MRI images by more accurately discerning whether or not the signal in an MRI receiving coil is corrupted by transient noise. By more accurately determining whether transient interference is present, appropriate steps can be taken from preventing these transient interference signals from being used to produce image data. These and other advantages of the present invention will be apparent to one skilled in the art in light of the following specification when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an MRI system according to one aspect of the invention;
FIG. 2 is block diagram of one embodiment of the interference detector and suppressor of FIG. 1.; and
FIG. 3 is a block diagram of a prior art interference detector and suppressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described with reference to the accompanying drawings wherein like reference numerals correspond to like elements in the several drawings. A block diagram of an MRI system 10 is depicted in FIG. 1 . MRI system 10 includes a magnet assembly 12 , the details of which are not part of the present invention. As an illustrative example, magnet assembly 12 may include a polarizing magnet 14 and a radio frequency (RF) coil or antenna 16 , both of which generally surround a patient being imaged. RF coil 16 may be used to both transmit RF signals and detect the MRI image signals, or separate coils may be used for transmission and detection. The MRI image signals that are detected by RF coil 16 are first typically passed to a low noise amplifier or pre-amplifier 18 , which may have a gain of 30 dB and a noise figure of about ½ dB, although other values can be used. From amplifier 16 , the signals are passed along line 20 to interference detector and suppressor 22 , which is part of the present invention. After passing through interference detector 22 , the signals are sent along a line 24 to a signal processing and image construction module 26 , which may comprise a number of different components such as a down converter, computers, computer terminals, monitors, and memory devices. Signal processing and image construction module 26 forms no part of the present invention, and the details of one example of such a module can be found in U.S. Pat. No. 5,525,906, the disclosure of which is incorporated herein by reference.
Interference detector and suppressor 22 determines whether the MRI signals coming in on line 20 likely contain transient interference that would improperly be interpreted as image, or desired, signals. In general overview, interference detector and suppressor 22 operates by recognizing that the transient interference, such as sparks, will virtually always have an envelope that varies at a significantly greater rate than the other signals in the system. By detecting a high rate of envelope change in the incoming signals, interference detector and suppressor 22 determines that the incoming signal is likely corrupted with transient interference, and the appropriate action is taken.
The signals coming in on line 20 are made of three different types of signals: (1) the desired signals, which are used to generate images, (2) thermal noise, which is always present, and (3) transient interference, which occurs sporadically and usually is the result of sparks, or other temporary interference events. The desired signals have a known frequency range that is narrow with respect to the other two signals. The desired signals are centered around the Larmor frequency and may have a bandwidth of approximately two-hundred to four-hundred kilohertz. The thermal noise is present at all frequency levels but is limited in MRI system 10 by the bandwidths of receiving antenna 16 and low noise amplifier 18 . Receiving antenna 16 and amplifier 18 are generally tuned to have a maximum gain over a relatively narrow bandwidth around the desired frequency range, while having substantial gain over a wider frequency range of several tens of megahertz (typically 40 MHz). The thermal noise therefore has a much wider bandwidth than the desired signals. The transient interference or noise spikes usually manifest themselves as impulse events, such as small sparks that are near enough to receiving antenna 16 to induce a voltage in antenna 16 . As such, the noise spikes have a very broad frequency component.
The voltage induced in receiving antenna 16 by the sparks will be transferred to interference detector and suppressor 22 according to the impulse response of antenna 16 and amplifier 18 . According to linear system theory, this impulse response may be described as a carrier frequency with an associated envelope wherein the envelope will have characteristics that are dominated by the bandwidth of antenna 16 and amplifier 18 . Because antenna 16 and amplifier 18 have a much wider frequency response than the desired signal's bandwidth (typically by a factor of 100 to 1000), the envelope of the noise spike will exhibit a rate of change that is much faster than the envelope of the desired signal. The envelope of the noise spike will also change much faster than the envelope of the thermal noise, which remains nearly constant.
The detailed operation of interference detector and suppressor 22 is best explained with reference to FIG. 2 . Interference detector and suppressor 22 has line 20 as its input, which is split between a detect path 28 and a signal path 30 . Signal path 30 is fed into a switch 32 which allows signal path 30 to be directly coupled to output 24 when switch 32 is closed. In this embodiment, switch 32 is closed when no interference is detected, and opened when interference is detected. The opening of switch 32 is referred to as blanking as it prevents the MRI signal on signal path 30 from being fed into signal processing and image construction module 26 . Switch 32 is controlled by an interference detector 34 placed along detect path 28 . Interference detector 34 , in the illustrated embodiment, includes a detector log video amplifier (DLVA) 36 , a high pass filter 38 , and a comparator 40 . In the current embodiment, DLVA 36 is a 0.1 GHz to 2.5 GHz, 70 dB Logarithmic Detector/Controller model AD8313 sold by Analog Devices, Inc. which has a place of business in Norwood, Mass. Other detector log video amplifiers can, of course, be used within the scope of the invention. The details of the model AD8313 can be found in the accompanying technical data sheet (revision B) published by Analog Devices, Inc., and downloadable from the web site http://www.analog.com the disclosure of which is hereby incorporated herein by reference. Although other high pass filters may be used, high pass filter 38 is a 500 KHz, three pole filter in the current embodiment. Comparator 40 may be any circuit that produces an output based upon the comparison of two inputs.
Detector log video amplifier 36 provides an output to high pass filter 38 that has a voltage corresponding to the power of the signal on detect path 28 that is input into DLVA 36 . For example, if the model AD8313 is used for DLVA 36 , it will output a voltage of approximately 0.6 volts, 0.8 volts, 1 volt, and 1.2 volts for input powers of −60 dBm, −50 dBm, −40 dBm, and −30 dBm, respectively (at approximately 900 MHz). The power of the input to DLVA 36 is a parameter that varies as the envelope of the input to DLVA 36 varies. Measuring changes in the power of the input to DLVA 36 therefore allows for changes in the envelope of the input to DLVA 36 to be detected. It will be understood by those skilled in the art that other devices could be used to detect the power of the incoming signal on detect path 28 , and that instead of measuring power, the envelope could be directly detected, or that other parameters that vary as the envelope varies could alternatively be detected. Because the envelope of interfering noise spikes will change at a much greater rate than the desired signals or the thermal noise, the output of DLVA 36 will vary greatly only when an interfering noise spike is present. High pass filter 38 distinguishes between the interfering noise spike and the desired signals and thermal noise by substantially filtering out the low frequency components of the output of DLVA 36 that are due to the desired signals and the thermal noise.
The output of high pass filter 38 is fed into a first input 44 of comparator 40 which compares its value to the value of a reference voltage 42 that is fed into a second input 46 of comparator 40 . If the value of first input 44 exceeds the value of second input 46 , comparator 40 outputs a high signal (an interference signal) at its output 48 . The output 48 of comparator 40 is optionally, though preferably, fed into a retriggerable multivibrator 50 which outputs a high signal (or blank signal) at 52 for a predetermined time period when its input receives a high signal. The purpose of multivibrator 50 is to provide a uniform blanking period when interference is detected by detector 34 . While the duration of the blanking signal output from multivibrator 50 can be varied as desired, the duration of the blanking signal is preferably equal to the sampling rate of an analog-to-digital (A/D) converter (not shown) that converts the analog signal on path 30 to a digital signal. This A/D converter is located in signal processing and image construction module 26 , and preferably converts the analog signal on path 30 to digital after the analog signal has been down-converted to lower frequencies. In the current embodiment, this sampling period is five microseconds, and multivibrator 50 outputs a five microsecond pulse every time its input goes high to thereby assure that the MRI signal on path 30 will be blanked for five microsecond increments.
Reference voltage 42 is preferably set at a value that is 6 to 10 dB above the thermal noise floor, although other values ranging from 2 to 20 dB and beyond can be used within the scope of the invention. In order to set reference voltage 42 a desired amount above the thermal noise floor, it is necessary to know the slope of the input/output characteristics of DLVA 36 . For example, if DLVA 36 has a 20 millivolt output for every one dBm of input power, then reference voltage 42 should be set at 120 millivolts (6 dBm×20 mV/dBm) to be 6 dB above the thermal noise floor. If it were desired to set reference voltage 42 at 10 dB above the thermal noise floor, it should be set at a value of 200 millivolts (10 dBm×20 mV/dBm). Setting the value of reference voltage 42 is therefore dependent only upon the slope of the input/output characteristics of DLVA 36 and the desired level above the thermal noise floor. This provides the advantage that detector 34 does not need to be re-adjusted or replaced when it is used in different temperature environments, or even when it is used with different antennas 16 that may have different thermal noise characteristics. While changing antennas or the temperature may cause a change in the average power of the thermal noise, these changes will be relatively slowly varying. As such, they will be filtered out by high pass filter 38 . For example, suppose the thermal noise floor initially presents −50 dBm of power to the input of DLVA 36 , causing DLVA 36 to output a signal of 0.8 volts. The 0.8 volt output of DLVA 36 will be generally constant (i.e. slowly changing) and therefore filtered out by high pass filter 38 . The same is true if the thermal noise floor changes to a power of −40 dBm, causing a change in the output of DLVA 36 from 0.8 to 1 volt, or some other value. Because this change is slow with respect to the envelope changes of the interference signal, it will be filtered out by high pass filter 38 . Detector 36 therefore provides the advantage that reference voltage 42 need not be changed once it is set, despite changes to the thermal noise brought about by changing temperatures or changing antennas.
Various modifications can be made to the embodiment described above without departing from the scope of the invention. One such change is reversing the order of high pass filter 38 and detector log video amplifier 36 such that detect path 28 is first fed into high pass filter 38 whose output is then fed into DLVA 36 . Another change is the addition of a delay filter in signal path 30 to create a delay in signal path 30 equal to the delay of detect path 28 . Another change is to use comparator output 48 to trigger corrective action other than blanking, such as, for example, re-scanning of the area corresponding to the corrupted signal. As still another change, a low pass filter might be inserted between the output of DLVA 36 and the input to high pass filter 38 . Such a low pass filter might be a single pole filter with a cut-off frequency of around ten megahertz. The low pass filter would help avoid false blanking due to random fluctuations in the thermal noise floor by filtering out any such high frequency random fluctuations. Further possible modifications include the use of a bandpass filter for filtering the input 20 into noise detector and suppressor 22 . Such a filter may be used to reduce thermal noise and remove inconsequential frequencies that are widely offset in frequency from the desired signals. A different type of envelope detector other than DLVA 36 may also be used.
While the present invention has been described in terms of the preferred embodiments depicted in the drawings and discussed in the above specification, along with several alternative embodiments, it will be understood by one skilled in the art that the present invention is not limited to these particular embodiments, but includes any and all such modifications that are within the spirit and the scope of the present invention as defined in the appended claims. | An improved transient interference detector and suppressor for an MRI system detects the presence of transient interference in an MRI signal by detecting the envelope of the MRI signal and comparing the rate of change of the envelope to a reference signal. When the rate of change of the envelope exceeds the reference signal, a transient interference detection is made and appropriate action may be taken. When the rate of change of the envelope is less than the reference signal, no transient interference detection is made. The reference signal is set at a level slightly above a level corresponding to the average thermal noise in order to substantially prevent the minor, random fluctuations in the thermal noise from falsely triggering the detection of a transient interference event. | 6 |
This invention was made with Government support under DOE Contract No. DE-FC05-97OR22605 awarded by the U.S. Department of Energy. The Government has certain rights to this invention.
TECHNICAL FIELD
This invention relates generally to an nozzle and more specifically to a nozzle tip for a fuel injector used with the internal combustion engine.
BACKGROUND
Manufacturers of internal combustion engines are continuously attempting to improve on the efficiency and emissions output of internal combustion engines. In diesel engines, a large amount of research has been done to reduce NOx output of an engine, through the use of improved fuel injectors and injection timing. Typically, combustion takes place over approximately 40 to 50 degrees of crankshaft rotation. A nozzle tip for a fuel injector in a typical modern diesel engine includes an end portion, the end portion includes a plurality of nozzle openings. High pressure fuel is forced into the end portion and sprayed into the combustion chamber as the piston nears top dead center. The nozzle openings are oriented to spray fuel at an angle of 60 to 80 degrees from a longitudinal axis of the injector.
Research has revealed that NOx emissions can be greatly reduced at partial load through a Homogeneous Charge Compression Ignition (HCCI). This is accomplished by injecting fuel into the cylinder at a much earlier stage in the combustion cycle. In this case, earlier, refers to the piston being farther from the cylinder head during the compression stroke of the engine, as the piston moves toward the cylinder head. The early injection permits fuel and air to more thoroughly mix, because in part there is a larger area between the top of the piston and the cylinder head. Having fuel and air more thoroughly mixed creates more complete combustion.
Using a conventional injector tip configuration to achieve Homogeneous Charge Compression Ignition operation of an internal combustion engine results in fuel being sprayed in an undesirable pattern causing inadequate mixing. For example fuel may cling to the cylinder walls and other surfaces and not properly mix with air. This is because of the direction of the nozzle openings is toward the cylinder walls and the piston is so far from the fuel injector. By changing the angle of the nozzles in relation to the longitudinal axis, fuel can be directed toward the top surface of the piston. Changing the angle of the nozzle openings creates a new problem, fatigue life of the nozzle cavity at the entrance of the nozzle opening may be reduced using conventional tip geometry.
The present invention is directed to overcoming one or more of the above identified problems.
SUMMARY OF THE INVENTION
In a one aspect of the present invention, a nozzle tip for a fuel injector is provided. The fuel injector includes a longitudinal axis. The nozzle tip includes the end portion having a inner surface and a outer surface. A plurality of nozzle openings are disposed through said end portion and have a central axis. Each of the nozzle openings at an angle between the central axis and longitudinal axis of between 5 and 10 degrees.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial sectional illustration of an engine having a fuel injector embodying one aspect of the present invention.
FIG. 2 is an enlarged partial section illustration of the nozzle assembly of FIG. 1 .
FIG. 3 is an enlarged partial sectional illustration of the nozzle tip of FIG. 2 .
FIG. 4 is an enlarged partial sectional illustration of a nozzle tip embodying another aspect of the present invention.
DETAILED DESCRIPTION
Referring to FIG. 1 an engine 10 includes a block 12 having a plurality of cylinders 14 therein, of which only one is shown, and a cylinder head 16 includes and exhaust passage 18 and an intake passage 22 . An intake valve 24 is interposed the intake passage 22 and the cylinder 14 . An exhaust valve 26 is interposed the exhaust passage 18 and the cylinder 14 . A fuel injector 28 having a body 30 , a nozzle assembly 32 , and a end portion 33 is additionally positioned within the cylinder head 16 . The fuel injector 28 is substantially of conventional construction, such as the type use with a hydraulically actuated electronically controlled unit injector system
The fuel injector 28 includes a body 30 having a longitudinal axis 34 , an upper end 36 and a lower end 38 . An electronically actuated solenoid 42 is removably attached to the upper end 36 . A nozzle assembly 44 is removably attached to the lower end 38 .
Referring now to FIG. 2, the nozzle assembly 32 includes an attachment portion 33 and a nozzle tip 60 . The attachment portion 33 is a substantially cylindrical member having an inner wall 48 , an outer wall 50 , a first end 52 and a second end 56 . The first end 52 is generally opened and adapted to engage the lower end 38 of the injector body 30 . The second end 56 is partially closed and defines an opening 58 that is adapted to receive a nozzle tip 60 in a conventional manner.
The nozzle tip 60 is a substantially cylindrical member having a first end 62 , a second end 64 , an outer surface 66 and an inner bore 68 . The inner bore 68 extends from the first end 62 toward the second end 64 . A seat 69 is defined within the inner bore 68 , preferably near the second end 64 . The inner bore 68 is adapted to receive a needle valve 70 . The needle valve 70 is moveable between a first and second position. The needle valve 70 includes a needle seat 71 that is adapted to engage the seat when in the first position. The outer surface 66 defines a shoulder portion 72 toward the first end 62 and a shank portion 74 interposed the shoulder portion 72 and the second end 64 . The second end 64 of the nozzle tip 60 includes the end portion 76 having an inner surface 78 and an outer surface 80 . A plurality of nozzle openings 86 extend through the end portion 76 and open at the inner surface 78 and the outer surface 80 . The nozzle openings 34 may be disposed about the longitudinal axis 34 .
Referring to FIG. 3, an embodiment of a end portion 76 of the present invention is shown. The inner surface 78 and outer surface 80 form a cylindrical portion 91 that is defined about the longitudinal axis 34 of the fuel injector 28 . The cylindrical portion 91 includes the end portion 76 and joins the inner bore 68 of the nozzle tip 60 opposite the end portion 76 . The end portion 76 forms a substantially large radius on the inner surface 78 and the outer surface 80 . The inner surface 78 and the outer surface 80 are spaced a predetermined distance from one and other. The nozzle openings 86 may be disposed evenly about longitudinal axis 34 . Each nozzle opening 86 includes a central axis 98 and a inside wall 100 . An intersection 99 is formed by the longitudinal axis 34 and the central axis 98 of each nozzle opening 90 . An angle α is defined between the longitudinal axis 34 and the central axis 98 . The angle α is preferably between 5 and 10 degrees. The nozzle openings 86 and each of the inner surface 78 and the outer surface 80 are substantially perpendicular to one and other. A radius 102 may additionally be formed at the intersection of the nozzle opening 86 and the inner surface 78 .
Referring to FIG. 4, another embodiment of a end portion 76 ′ is shown. The end portion 33 ′ joins the inner bore 68 of the nozzle tip 60 opposite the end portion 76 ′. The end portion 76 ′ forms a large radius on the outer surface 80 ′. A conical portion 106 is defined about the longitudinal axis 34 on the inner surface 78 ′. The nozzle openings 86 are disposed about longitudinal axis 34 . Each nozzle opening 86 includes a central axis 98 and a inside wall 100 . The central axis 98 of each nozzle opening 86 is substantially perpendicular to the conical portion 106 . An intersection 99 ′ is formed by the longitudinal axis 34 and the central axis 98 of each nozzle opening 86 . An angle α′ is defined between the longitudinal axis 34 and the central axis 98 . The angle α′ is preferably between 5 and 10 degrees. An angle β is defined between the longitudinal axis 34 and the conical portion 106 . Angle β is preferably between 100 and 110 degrees. A radius 102 may additionally be provided at the intersection of the inside wall 100 and the inner surface 86 ′.
INDUSTRIAL APPLICABILITY
In operation, a fuel injector 28 facilitates HCCI combustion by directing early injection of fuel into the cylinders 14 at a desired angle and pattern. The fuel is sprayed in a substantially downward direction, toward the piston, as the piston is moving toward the cylinder head 16 . The early injection allows a more thorough mixing of fuel and air because of a larger mixing area and more time before combustion. The more thoroughly mixed fuel and air mixture facilitates combustion at multiple sites in the cylinder 14 simultaneously resulting in more complete combustion and a reduction in NOx production.
The geometric design of the end portion 92 of and the orientation of the nozzles 90 directs a fuel spray in a substantially downward direction and appropriate pattern, preventing the fuel from clinging to the cylinder walls and promoting mixing of air and fuel. Additionally, the orientation of the nozzles 90 reduces the concentration of stresses in the end portion 76 ′, increasing the fatigue life of the nozzle tip 60 . | This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation (CIP) of application Ser. No. 11/030,682, filed Jan. 5, 2005.
FEDERALLY SPONSORED RESEARCH
Not applicable.
SEQUENCE LISTING OR PROGRAM
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to vehicle tire chains, specifically configurations and mounting methods that allow chains, as described, to be mounted onto a wheel more easily than previously possible.
2. Prior Art
Tire chains are available in many configurations, including the following: Chains are available made of steel link chain or made of multi-strand steel cable. The most common configuration of link type chains is the so called ladder type, consisting of two side members and a multiplicity of cross members arrayed on the tire tread and attached to the two side members. Other, more complex configurations made of link chain include a so called diamond pattern. Cable chain configurations include the ladder type and a so called diagonal or zig zag type pattern.
The diamond pattern is disclosed in U.S. Pat. No. 3,842,881, Oct. 22, 1974, Muller et al, and the zig zag pattern in U.S. Pat. No. 5,056,574 Oct. 15, 1991, Maresh, et al, and several earlier patents, including U.S. Pat. No. 1,486,993, Mar. 18, 1924, Stolpe. Both of these patterns utilize a distinctive mode of installation on the wheel, involving arraying the chain on the ground in front of the wheel, sweeping it to the rear of the wheel and drawing chain elements forward for fastening, including drawing lower chain portions around the tire to ground contact area. While this mode is claimed to be “easy mounting”, the step of sweeping the chain to the rear of the wheel can be quite inconvenient in soft snow or mud.
The ladder pattern and other patterns typically use the drive-over method of chain installation.
BRIEF SUMMARY OF THE INVENTION
The present invention discloses improvements in a category of vehicle tire chains which utilizes the mounting step of imposing cross chains on the tire to ground contact area. These improvements include configurations for easier mounting, improved stabilization of the chain against operating forces, and an improved method of vending the chain.
OBJECTS OF THE INVENTION
An object of this invention is to provide a vehicle tire chain which is easier to install on a wheel than the prior art.
A further objective is to provide an easy to mount tire chain, which can be fully mounted during one stop of the vehicle.
A further object is to provide an easy to mount tire chain which can be mounted during one stop of the vehicle and will be self actuating to provide adequate traction elements uniformly over the tire tread, specifically to fill in the tire to ground contact area, not covered upon initial mounting.
A further object is to provide an easy to mount tire chain which can be mounted during one stop of the vehicle and which will be fully serviceable in resisting and tolerating random operating forces significantly greater than normal, such as those from heavy braking, turning and skidding.
It is an additional objective to use the principles of this invention to enable a specific, given chain, to fit a broader range of tire sizes, to improve the marketing economics, as to manufacturing cost, inventory and parts supply.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan view of a zig zag pattern tire chain.
FIG. 2 is a schematic partial plan view of the tire chain of FIG. 1 .
FIG. 3 is a schematic elevation of the chain of FIGS. 1 and 2 , using a known art tightener configuration.
FIG. 4 is a schematic elevation of a zig zag pattern chain using a six hook elastic tightener loop and a non elastic stabilizing connector.
FIG. 5 is a schematic elevation of a zig zag pattern chain using an elastic tightener band on the lower segment of the side chain and a non elastic loop hooked to other segments.
FIG. 6 is a cross member extension device for link chains.
FIG. 7 is a cross member extension device for cable chains.
FIG. 8 is a cross member extension device fitted with a non return feature.
FIG. 9 is a schematic plan of a ladder chain fitted with two cross chain extensions.
FIG. 10 is a schematic plan of a ladder chain with two deflected cross chains oriented diagonally.
FIG. 11 is a schematic elevation of a chain with two deflected cross members fitted with extension device.
FIG. 12 is a schematic elevation of a chain with one deflected cross member fitted with extension device.
FIG. 13 is a view of equivalent tire sizes for tire chain supply.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention can only be adequately understood by noting the operating characteristics of the known art which the present invention is applied to.
A commercially popular model of tire chain is based generally on Maresh, et al, U.S. Pat. No. 5,056,574, and is shown in FIGS. 1 , 2 , and 3 . The Maresh chain utilizes a diagonal pattern, or so called zig zag pattern of cross chains. Six repetitions of the pattern are generally sufficient for a passenger car tire chain. Six repetitions leaves room for significant slack in the side chains, between attachment points of paired cross chains. The chain is stabilized by a loop of elastic band 55 , hooked into each side chain segment, using hooks 59 in FIG. 3 .
This elastic loop serves to provide both a required tensioning function and a required chain stabilizing function. The tensioning function is required because the mounting procedure involves imposing an adjacent pair of cross chains upon the contact area between the tire and the ground or roadway. This deflects the two cross chains 51 and 52 in FIGS. 1 , 2 , and 3 , causing the cross chain ends to retract from the side chain connections, thus depressing the side chains.
The cross chains must be pulled into their normal operating positions, when the wheel is turned, releasing the tire to ground contact pressure. The tension required to move the chains is quite small, on the order of a pound, but it is an important function.
The inner face side chain is inaccessible, so the tension must be applied to the outer face side chain.
The other function, that of stabilizing the chain against operating forces, is much more demanding, in terms of force levels, as the primary chain elements, cross chains and side chains, must withstand normal operating forces due to driving, turning, braking, and also higher level forces such as severe braking and skidding.
The elastic loop 55 in FIG. 3 performs the tensioning function quite well, but random operating forces can exceed the capability of the elastic loop to withstand. The present invention involves replacing the elastic loop with a combination of elastic connectors and steel, or non elastic connectors, arranged to fulfill the two necessary functions, tensioning and stabilizing.
The stabilizing function can be greatly improved by the use of steel or non elastic connectors, in conjunction with the elastic tightener. There is a myriad of possible patterns for such steel connectors. A minimum configuration would be a single strand of chain, oriented horizontally (during mounting) and hooked to the side chain segments on each side of the lateral attachment points. ( 61 in FIG. 4 ).
Some stabilization will extend to the other four attachment points, above and below. The six hook elastic band 62 , used for tensioning, will add further stabilizing to the upper and lower attachment points.
The release of the deflected cross chains upon vehicle movement allows the bottom segments of both the outer face side chain and inner face side chain to rise. The rear face action can be passed up the rear face and over the top resulting in a dropping of the outer face side chain top segment. In FIG. 5 , elastic band 71 is hooked to the lower segment of the outer face side chain and to the upper segment connections, and a non elastic connector is hooked to the other segments.
In the chain of FIG. 5 , tension is applied to the outer face top and bottom segments, to ensure proper repositioning of the deflected cross chains. An elastic tightener band will suffice.
As a matter of technique, the steel connector, or connectors, would be hooked onto the side chain, before the side chain is hooked to itself to form a loop on the wheel. That attachment will tighten the side chain into the multiplicity of hooks on the steel connector.
After the side chain is connected, the tightener band is applied, which will further integrate the assembly. The tension at each hook need not be excessive, as there is no elasticity in the steel connectors.
A no slack side chain is greatly distinguished from the above described high slack chain, in that the no slack chain is self stabilizing when fully mounted.
The present invention includes a somewhat more advanced solution to the situation described above with the high slack chain. The innovation is to provide a sliding connection of the deflected cross chains, such as 51 and 52 in FIGS. 1 , 2 , and 3 , to the outer face side chain 22 . The purpose is to allow the deflected cross chains to retract through the sliding connections, when imposed upon the tire to ground contact area. This allows the outer face side chain to be fully connected (to itself) during the initial mounting procedure, without regard to the position of the deflected cross chains.
FIG. 6 , for link chain, and 7 , for cable chain, show the cross chain extension and sliding connection to the outer face side chain 22 . Tension devices 82 , typically elastic tightener bands, are attached to the extended ends of the cross chains, to pull the deflected cross chains 81 into position, upon initial operation of the vehicle.
To prevent random operating forces from pulling the deflected cross chains back through the sliding connections, a non return device can be built into the sliding connection. There is a myriad of ways such a device could be configured. It can be as simple as a notch 85 on the side of a flat bar, as in FIG. 8 , which engages a stop bar 86 on the side chain, to prevent return movement. This device must be rugged and sturdy to withstand unusually high random operating forces, for instance a skid onto bare pavement.
FIG. 9 shows the cross chain extensions 91 and 92 applied to adjacent cross chains 93 and 94 in a ladder pattern tire chain. It is advantageous to orient the cross chains diagonally, as 95 and 96 in FIG. 10 , to shorten the distance between fully connected adjacent cross chains 97 and 98 , and to improve the support for the sliding connections.
FIG. 11 shows two deflected cross chains fitted with extensions 99 and 100 and tensioned by elastic bands 101 and 102 . FIG. 12 shows a single cross chain extension.
In the commercial marketing of tire chains, it is highly desirable that a given tire chain fit the largest possible range of fire sizes, in order to minimize the required inventory to stock chains for sale for all tire sizes. The principles of the present invention can be utilized to help meet this objective. The following discussion relates only to fire chains which have relatively long segments of the outer face side chain, such as the zig zag and diamond patterns. Excluded from this discussion would be the ladder and similar patterns. The discussion does relate to both cable and link type construction.
The chain to suit a certain tire size will have the appropriate diameter of both inner and outer face side chains, as well as the appropriate length of cross members. That chain can be used, as is, for all equivalent tire sizes, in which a decrease in tire diameter is matched by an increase in width, or an increase in tire diameter is matched by a decrease in width, as shown in FIG. 11 , so the side chains stay at the same diameter. The limit of this variation is the preferred minimum distance from each side member to the outer tire diameter.
That chain, as selected, can not be used for a larger tire size (larger than the equivalent tire sizes) as the side chain diameters are set; that is, increasing the diameter of a side chain or the length of cross chains makes it a different chain, by definition.
The selected chain can readily be used for a smaller tire size by arranging to take care of the slack in the outer face side chain segments, between the cross chain attachment points, created by moving the cross chain attachment points on the outer face to a smaller effective diameter of the side chain, as defined by the cross chain attachment points.
Examples of the elastic tensioning devices and non elastic stabilizing devices which make up the connector sets to put with the basic chain, are shown in FIGS. 4 and 5 .
Since it is impractical to change the inner face side chain diameter, it is preferable to start with the minimum practical inner face side chain diameter, leaving the greatest room to reduce tire diameter, without going below the desired minimum clearance of inner face side chain diameter and tire diameter. This discussion assumes that all size variations are taken into account at the outer face side chain.
The novel features of the present invention are entirely usable for tire chains for dual wheels.
All of the chains claimed in this application can be adapted to a mounting method of “sweeping about the bottom of the tire”, as described in Maresh, et al, or the “over the top” mounting method described in inventor's earlier application, as both employ the step of imposing cross chains onto the tire to ground contact area, which these disclosures are based on. Only the “over the top” method can be used on dual wheels, whether the chain be single or dual, as the second wheel interferes with the “sweep about the wheel”.
It will be evident to those skilled in the art that many variations can be made in the configurations, which are not herein described in detail. Such variations should be considered to be within the scope of the invention if within the encompass of the appended claims. | Configurations and installation methods for vehicle tire chains which provide tire chains especially easy to mount, and provide improvements in performance and vendor supply. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to radar level gauge (RLG) systems. In such systems, microwaves are emitted into a tank and a reflected tank signal is received. Based on signal processing of this reflected signal, a process variable such as the level of a content in the tank can be determined
BACKGROUND OF THE INVENTION
[0002] Such RLG systems typically include a signal generator, means to emit the signal into the tank, and a receiver for receiving the reflected tank signal. The received signal can for example be a time domain reflectometry (TDR) signal or a frequency domain signal, such as a frequency modulated continuous wave (FMCW) signal. The received signal typically comprises at least a surface reflection (echo) caused by an interface between different materials in the tank, typically but not necessarily a liquid surface. Normally, the received signal also includes various interfering reflections caused e.g. by the bottom and walls of the tank or the transition between the signal generator and the wave guide.
[0003] In order to improve the accuracy of the measurement result, the signal processing of the received signal can be adapted to compensate the received signal for such interfering reflections. However, the signal processing is typically optimized in terms of general precision in the entire tank, and is not necessarily optimal in all areas of the tank. Therefore, in addition to the RLG system, additional sensors are sometimes arranged in the tank, in order to provide information about conditions in specific regions of the tank.
[0004] One such region of special importance is the near zone, i.e. in a region close to the entry of microwave into the tank. In an RLG measurement process can be complicated or even made impossible, when the surface reflection occurs in this near zone, which can be in the range of 0 m to 2 m depending on the type of microwave signal used. The problems are caused by an interfering reflection caused by the transition between a signal transfer medium and the emitter/receiver in the tank, in combination with the limited bandwidth limiting the resolution. RLG systems may be provided with specific signal processing to handle such problems.
[0005] At the same time, for security reasons it is very important to have a secure indication of if and when the surface of the contents in the tank approaches the top of the tank, i.e. some kind of overfill sensing system. Therefore, one example of an additional sensor mentioned above is an overfill sensor, arranged in the top of the tank and adapted to detect when the level exceeds a certain level. Although the normal measurement processing may be adapted to provide accurate measurements also in the top of the tank (referred to as the near zone), such a redundant sensor system is required by authorities in many countries
GENERAL DISCLOSURE OF THE INVENTION
[0006] It is an object of the present invention to provide information about conditions in specific regions of the tank, without the need for additional sensors.
[0007] This and other objects are achieved by providing a radar level gauging method and system for processing a tank signal comprising consecutive tank signal portions each corresponding to a measurement cycle, wherein each portion of the received tank signal is processed in a plurality of processes, each process being adapted to determine a process variable in a specific region of the tank, each specific region corresponding to a separate predefined propagation distance range.
[0008] The term “measurement cycle” is here used to indicate the cyclic process of determining a measurement result. The cycles are not necessarily equal in length, and the content of the transmitted signal may also very between different cycles. In a pulsed RLG, a measurement cycle corresponds to the transmission of one pulse, while in a FMCW RLG a measurement cycle corresponds to one sweep of frequencies. As each portion of the tank signal corresponds to one measurement cycle, each of the plurality of processes will be performed on information from each measurement cycle.
[0009] One region may be the area closest to the signal entry into the tank (referred to as the near zone), while another region may be the area furthest away from the signal entry into the tank. In a vertically oriented tank, the regions corresponding to different propagation distance ranges will relate to vertical layers of the tank, e.g. a top region and a bottom region.
[0010] Such multi-processing of the received tank signal has the advantage that each process can be optimized to that particular region of the tank. More specifically, a process concerned with a particular region of tank only needs to treat a limited content of the tank signal. In the case of a time domain reflectometry signal, the process only needs to handle a limited time range, and in the case of a frequency domain tank signal, the process only needs to handle a limited frequency range. The processing is thus simplified, and such a regionally limited process can be made more robust.
[0011] It should be noted that the regions may overlap, so that a portion of the tank may be covered by several regions. The tank signal relating to this region will this be processed in several processes. This will be the case, for example, if one process handles essentially the entire tank, in order to obtain a measurement result, while other processes only handle smaller sub-regions, i order to provide more robust measurements of these specific regions.
[0012] Such a regionally limited process can include subtracting a compensation signal from the tank signal, which compensation signal includes background information about the region of interest, also referred to as a “signature”. Such a compensation signal can be formed using a tank signal in which the surface reflection occurs at a distance from the region of interest, and then extracting the portion of the tank signal relating to the region of interest
[0013] In a pulsed, time domain, system, the relevant portion of the tank signal may be extracted by selecting a time range of the signal.
[0014] In a frequency domain system, such as an FMCW system, the compensation signal can be formed by low pass or band pass filtering a tank signal received when no surface reflection occurred inside the region of interest.
[0015] For a bottom region of the tank, a compensation signal can be formed by saving a tank signal from a measurement cycle when the surface reflection is close to the bottom.
[0016] In any case, an updated compensation signal CS n *(t) can be formed by combining the compensation signal CS n (t) with a previous compensation signal CS n-1 (t), according to
CS n *( t )= aCS n ( t )+(1 −a ) CS n-1 ( t ),
where a is a weight factor between zero and 1.
[0017] One example of a regionally limited process can be a near zone process, especially adapted for the near zone, suitable for providing an overfill detection system. This embodiment of the invention is based on the realization that while a redundant overfill sensing system is often required, the RLG system itself is in fact capable of providing such sensing, as long as the suitable signal processing is applied. By applying such signal processing in a separate measurement process, a redundant overfill detection system is provided within the RLG system, thus eliminating the need for a separate sensor.
[0018] The near zone process can be limited to treating the signal content originating from the near zone of the tank, and does therefore not have to handle interference from other regions of the tank. This makes the processing more robust, to the degree that it meets the requirement of an overfill sensing system.
[0019] According to one embodiment, a near zone process may include: for each portion of the received tank signal, subtracting a compensation signal CS n (t) based on a near zone signature of the tank from the received tank signal, and detecting a peak with an amplitude greater than a predetermined threshold in the near zone, monitoring if a peak occurs in a predetermined number of measurement cycles, and identifying a surface reflection based on said peak.
[0020] The compensation signal here includes information about the near zone of the tank, and is referred to as a near zone signature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other aspects of the present invention will be described in more detail with reference to the appended drawings, illustrating presently preferred embodiments.
[0022] FIG. 1 shows schematically a radar level gauge system according to an embodiment of the present invention.
[0023] FIG. 2 shows a block diagram of the signal processing according to an embodiment of the present invention.
[0024] FIG. 3 shows a flowchart of two of the processes in step FIG. 2 .
[0025] FIG. 4 shows a flow chart of the detector step in FIG. 3 .
[0026] FIG. 5 shows a state model of an alternative embodiment of the detector step.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0027] FIG. 1 shows a schematic block diagram of a radar level gauge (RLG) 10 , in which the present invention has been implemented. The gauge 10 is arranged to perform measurements of a process variable in a tank, such as th level of an interface 2 between two (or more) materials 3 , 4 in the tank 5 . Typically, the first material 3 is a content stored in the tank, e.g. a liquid such as gasoline, while the second material 4 is air or some other atmosphere. In that case, the RLG will enable detection of the level of the surface of the content in the tank. Note that different tank contents have different impedance, and that the electromagnetic waves will only propagate through some materials in the tank. Typically, therefore, only the level of a first liquid surface is measured, or a second liquid surface if the first liquid is sufficiently transparent.
[0028] The RLG 10 comprises a microwave controller 11 , a microwave emitter/receiver 12 , and a signal transfer medium 13 connecting the emitter/receiver 12 to the controller 11 . The controller 11 can comprise a transmitter 14 , a receiver 15 , a circulator 16 and any control circuitry 17 required to manage these components Further, the controller 11 can comprise an A/D-converter 18 for digitizing a tank signal, i.e. a signal received from the tank.
[0029] The emitter/receiver 12 can, as shown in FIG. 1 , include a free radiating antenna 19 in the top of the tank, or alternatively the emitter/receiver 12 can include a steel pipe acting as a wave guide, or a transmission probe (e.g. coaxial probe, single probe, or twin probe) extending into the tank.
[0030] The signal transfer medium 13 can be a wire or cable, but can also include more sophisticated wave guides. In case of a explosive or otherwise dangerous content in the tank 5 , the signal transfer medium 13 may include an air tight seal passing through the tank wall. It is also possible that the controller 11 is connected directly to the emitter/receiver 12 with a suitable terminal, or that the emitter/receiver 12 is arranged on the same circuit board as the controller 11 , in which case the signal transfer medium simply may be a track on the circuit board.
[0031] The radar level gauge 10 further includes processing circuitry 20 for communicating with the microwave controller 11 and for determining a measurement result based on a relation between transmitted and received microwaves The controller 11 is connected to the processing circuitry 20 by a data bus 21 , and is adapted to generate a microwave signal in accordance with control data from the processing circuitry 20 .
[0032] In use, the processing circuitry 20 controls the microwave controller 11 to generate and transmit a measurement signal to be emitted into the tank 5 by the emitter/receiver 12 . This signal can e.g. be a pulsed signal (pulsed level gauging) or a continuous signal with a frequency varying over a certain range (Frequency Modulated Continuous Wave, FMCW). The microwave emitter 12 acts as an adapter, enabling the signal generated in the controller 11 to propagate into the tank 5 as microwaves, which can be reflected by the surface of the material 3 .
[0033] A tank signal, i.e. the emitted signal and its echo, or a mix of emitted and reflected signals, is received by the emitter/receiver 12 , and communicated to the microwave controller 11 , where it is received by receiver 15 and A/D converted by converter 18 . The digitized signal is then provided to the processing circuitry 20 via bus 21 , and the processing circuitry 20 determines a measurement result based on a relation between the emitted and received waves.
[0034] According to this embodiment of the present invention, the processing circuitry is arranged to process the received tank signal in a plurality of processes, each process being adapted to determine a process variable in a specific region of the tank. This is illustrated in FIG. 2 . It should be noted that the processes do not need to be parallel as indicated in FIG. 2 . On the contrary, they can be performed sequentially, as long as they use the same input (tank signal portion) In FIG. 2 , three different processes 31 , 32 and 33 are shown, each being adapted to determine a process variable in a specific region 51 , 52 and 53 of the tank 5 in FIG. 1 . The results from the three separate processes are evaluated in an evaluation module 34 .
[0035] In the illustrated case one process 31 corresponds essentially to the conventional measurement process, and is intended to provide a measurement result, such as a tank level, that is valid in the entire tank. The process 31 thus treats the entire tank signal, and handles various types of interference that can occur in the tank.
[0036] The two other processes 32 , 33 are adapted to provide measurement results such as a tank levels in a limited region, here the near zone 52 and the bottom zone 53 , respectively. As these processes are only intended to provide valid results under certain circumstances, they can be made more robust, and can replace additional sensor systems sometimes required by authorities.
[0037] According to a preferred embodiment, one of the processes 32 is a near zone process, intended to function as an overfill detection process. The purpose of such a process is to securely detect any surface echo in an overfill region near the top of the tank, in order to avoid an overfill situation. If a surface echo is detected in the overfill zone, the output from the overfill protection system will be received by the evaluation module 34 , and can trigger an alarm, causing a shutdown of the pumping system connected to the tank Further, the evaluation module can be adapted to let the output from the overfill detection process 32 overrule the output from the normal measurement process 31 , as the near zone process 32 is considered to be more robust in this region of the tank. In an ideal situation, the normal process 31 will detect the same surface echo as the overfill detection process 32 , but there is a risk that the normal process has been disturbed by interferences from the tank and produces an erroneous result.
[0038] An overfill detection process according to an embodiment of the present invention is illustrated in more detail in FIG. 3 , in a schematic block diagram showing examples of the processes 31 and 32 . It should be noted that this embodiment relates to a frequency modulated continuous wave (FMCW) system. However, a similar system could be implemented in a pulsed system with only minor modifications.
[0039] As is clear from FIG. 3 , the process 32 is arranged to process the same input signal (tank signal) as process 31 , and also includes many of the same steps. More specifically, process 31 includes process step S 1 , for adapting the gain of the tank signal, step S 2 , for Fourier transforming the tank signal and providing a tank signal spectrum, step S 3 for locating any peak in the spectrum, step S 4 for determining distance from tank entry and amplitude, step S 5 for tracking a surface echo, and step S 6 for identifying an echo. The near zone process 32 , on the other hand, includes process step S 7 -S 11 , of which steps S 8 -S 10 essentially correspond to steps S 2 -S 4 of process 31 .
[0040] In step S 7 , a compensation is subtracted from the tank signal. This compensation signal includes background information from the near zone, and can be deduced from an earlier tank signal, where the surface reflection was established to be well outside the near zone. Here, as the tank signal is an FMCW signal, such a near zone signature can be generated by low pass filtering the tank signal. The low pass filtering has three purposes: first of all, it eliminates the surface reflection from the signal, secondly, it allows sampling of the compensation signal, and thirdly, it avoids high frequency content having non-stable phase.
[0041] In step S 8 the tank signal is Fourier transformed to create a spectrum, just as in step S 2 in process 31 , and in step S 9 a peak is located by simply finding a local maximum (a bin larger than its neighboring bins) In step S 10 the amplitude and position of this peak is determined, which is used in the following step S 11 .
[0042] In step 511 it is determined if the peak represents a surface echo within the overfill region, and if so an output is generated.
[0043] Step S 11 is preferably designed so as to avoid unnecessary alarms, as this would result in unwanted costs. In a simple case, step S 11 monitors the occurrences of peaks in the overfill region by a counter. This is illustrated in FIG. 4 . First in step S 12 it is verified that the peak is within the overfill region. In step S 13 it is then verified that the amplitude of the peak is greater than a predefined threshold If a valid peak is detected, a counter is increased in step S 14 , but preferably only up to a specified limit If no valid peak is detected, the counter is decreased in step 515 . Thus, each measurement cycle that a valid peak is detected in the overfill region, the counter is increased, and each cycle no peak is detected the counter is decreased. In step 516 it is checked if the counter exceeds a predefined threshold, and if this is the case, the valid peak is considered as a surface echo in the overfill region, and an output is generated in step S 17 . In order to make the process more robust, an hysteresis can be introduced by providing an output until the counter falls below a second threshold, lower than the first threshold.
[0044] A more sophisticated process that can be implemented in step S 11 is shown in FIG. 5 as a state model. According to this process, a pre-region is defined immediately outside the overfill zone, and in addition to the counter for counting peak detections in the overfill zone, there is a pre-counter for counting peak detections in the pre region. The states 61 - 65 are labeled No peak, Pre-region Enter zone, inside zone and Leave zone.
[0045] The No peak state 61 is reached when both counters are equal to zero. As soon as a peak with sufficient amplitude is detected inside the pre-region the Pre-region state is reached. If, on the other hand a peak with sufficient amplitude is detected inside the overfill zone the Enter zone state is reached.
[0046] In the Pre-region state 62 , a process similar to the one in FIG. 4 is run. The pre-counter is increased for each measurement cycle for which a valid peak is detected in the pre-region, and decreased for each cycle for which no peak is detected. During periods when the pre-counter exceeds a predefined threshold, step S 11 of the overfill detection will generate an output, indicating a surface echo in the pre-region. If the pre-counter reaches zero, program control returns to the No peak state 61 . If a peak instead is detected in the overfill zone, program control proceeds to the Enter zone state 63 .
[0047] In the Enter zone state 63 , also a process similar to FIG. 4 is run. The counter is increased for each measurement cycle for which a valid peak is detected in the overfill zone, and decreased for each cycle for which no peak is detected. If the counter reaches zero, the program control returns to the Pre-region state 62 if the pre-counter is greater than zero, or to the No peak state 61 if the pre-counter is also zero. If the counter instead exceeds a predefined threshold, the program control proceeds to the Inside zone state 64 . This threshold can be different from the threshold in the Pre-region state 62 .
[0048] While in the Inside zone state 64 , step S 11 of the overfill detection process 32 will generate an output, indicating the current position of the detected peak. Program control will remain in the Inside zone state 64 as long as peaks are detected in the overfill zone, and the counter will be increased up to a predefined level, possibly equal to the threshold in the Enter zone state 63 . As soon as a measurement cycle detects no peak with sufficient amplitude in the overfill zone, program control will proceed to the Leave zone state 65 .
[0049] While in the Leave zone state 65 , step S 11 of the overfill detection process 32 will generate an output, indicating the position of the last detected peak. For each cycle without peak in the overfill zone, the counter will be decreased, and when below a predefined threshold, program control will return to the Enter zone state 63 , and no output will be generated. This threshold is preferably lower than the threshold in the Enter zone state 63 thereby creating a hysteresis effect. If a new peak is detected in the overfill zone before the counter has fallen below this threshold, program control will instead return to the Inside zone state 64 and again output the current position of the peak.
[0050] When the near zone process 32 is implemented as an overfill detection process as described above, it may be required by regulations to ensure that the process does not fail, and various checks can be implemented for this purpose. One such check is a sweep fail check, which raises an alarm if too many measurement cycles fail, e.g. due to linearization errors or tank signal clipping. A sweep fail check can be implemented by letting a counter count each failed measurement cycle and determine a ratio between the number of failed cycles and the total number of cycles. If this ratio exceeds a given threshold, an alarm is raised.
[0051] Although described mainly with reference to a FMCW system, it should be realized that the present invention can be advantageously applicable to any RLG system. More specifically, the above described overfill detection process 32 , can be adapted for a pulsed, time domain, system. Such a process will not require Fourier transformation of the tank signal, and will identify peaks in the time domain instead of in the frequency domain. The near zone signature will further not be a 1 c pass filtered tank signal, but a selected time range frc the tank signal. The overall structure of the process 32 will however remain intact.
[0052] Further, it should be noted that the number of processes is not limited to three, as shown in FIG. 2 . On the contrary, an implementation of the overfill detection system described only requires two processes, and it may be advantageous to implement more than three | A method and a system for processing a reflected microwave signal generated by a radar level a gauge system arranged to transmit microwaves towards the material in the tank, and receive a reflection of said microwave signal as a tank signal. The tank signal is processes by a plurality of processes, each process being adapted to determine a process variable in a specific region of the tank, each specific region corresponding to a predefined propagation distance range. Such multi-processing of the received tank signal has the advantage that each process can be optimized to that particular region of the tank. More specifically, a process concerned with a particular region of tank only needs to treat a portion of the tank signal. | 6 |
The present invention relates to a screw. In particular, even though not exclusively, the invention relates to a wood screw.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Wood screws belong to the most widely used fasteners in many different applications. For instance, it is often required that a wood screw be capable of fixedly holding a hardware such as a hinge wing or railway clamp. Another requirement often raised is that the specific axial pressure active under the screw head of a tightened screw be as low as possible while securing a firm hold. Another requisite Is that the screw be capable of being applied without the need for countersinking the head as this requires an extra machining of at least one of the parts being joined. By the same token, it is often required that the screw positioned in place be as unobtrusive as possible on the surface to avoid the danger of injury, for instance, to animals in zoo structures, to children and to the general user.
2. Description of the Prior Art
Various types of screws are known which are directed to satisfy one or more of the above requirements. For instance, it known from Italian Patent 475002 Manfroni! to provide a railway clamp fastening wood screw which includes a cylindric portion of the shank of the screw above the threaded portion of the shank and just below the head. The cylindric portion is closely compatible with a bore in the railway clamp through which the screw passes into the wooden tie to hold the clamp down. Viewed from the standpoint of the present invention, the screw has the drawback that the specific pressure under the screw head is relatively high and that an axially upwardly projecting portion is required for engagement with a torque applying tool, in this case a socket wrench. This type of screw therefore would be unsuitable for applications where the specific pressure must be low, the fastening force high and the surface head as flush as possible to avoid or at least substantially reduce the danger of injury to a child or an animal.
The torque tool engaging projection is known to be replaced with various cutouts compatible with tools such as screwdrivers and a variety of these exists, from plain straight grooves as in Canadian Patent 27,387 Rogers!, to more complex sockets such as shown e.g. in U.S. Pat. No. 5,249,882 Nagoshi et al.! Canadian Patent 400,454 Purtell!, Canadian Patent 1,248,374 Rockenfeller et al.! or Published Canadian Patent Application 2,094,478 Goss!.
Prior art screws are usually unsuitable for use with power tools, where the screw must withstand a relatively high torque while a low specific pressure under the head is required when the fastener is firmly in place. The screws having convexly shaped heads project above the surface of the workpiece often in obtrusive and potentially dangerous way which may cause injury.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a screw which would withstand a relatively high torque applied by a power tool, which would be capable, if required, to engage a predetermined size of a bore in a hardware such as a hinge wing, which could be applied, in case of a wood screw, without the need for pre-machining the surface of the workpiece to accommodate the screw head and which would, by the same token, exert a relatively small specific pressure under the head and would be of a configuration which projects from the workpiece surface in unobtrusive way, eliminating or at least substantially reducing the possibility of injury to the user of the particular workpiece.
In general terms, the invention provides a screw which comprises, in combination, a stem portion having a free end and a root end; a helical thread projecting from the surface of the stem portion; said root end being integral with and corresponding in diameter to a minor base end of a frustoconical portion projecting axially from and being coaxial with said root end; said frustoconical portion further including a major base end spaced from said minor base end, said major base end corresponding in diameter to and being integral and co-axial with a first end of a cylindric root portion; the other end of said cylindric root portion, in turn, merging with a flat annular underside of a washer section integral with and having a diameter which is a multiple of that of the second cylindric portion; said washer section including a flat, circular upper face section generally parallel with and turned away from said underside; and a centrally disposed shallowly convex head portion projecting centrally from said upper face section and generally coaxial therewith, said head portion being provided with centrally disposed drive tool engagement recess compatible with a predetermined tool for driving said screw.
The combination of the features defining the inventive screw may comprise further aspects. For instance, the root end of the stem is preferably cylindric. The helix usually extends over a major portion of the length of the stem portion. If the screw is a wood screw, the free end is pointed to facilitate its penetration into a wooden base.
The structure of the screw of the present invention will now be described in greater detail with reference to the accompanying drawings, by way of several embodiments of a wood screw. It being understood that the principles of the combined structure can be used in other types of screws or bolts.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a diagrammatic, enlarged side view of a wood screw including the combination of features according to the present invention;
FIG. 2 is a view similar to that of FIG. 1, in which the contour of a prior art screw of comparable size, with a hexagonal head is shown in broken lines for comparison of the contour of an applied screw;
FIG. 3 is a diagrammatic side view of a screw comprising the combination of the present invention, in which certain measurements are designated to provide examples of a number of variations in size; and
FIG. 4 is a top plan view of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The screw shown in the drawings is an integral product made from suitable steel, it being understood that certain applications may warrant or require different material, for instance nylon.
The screw shown in the drawings comprises a stem portion 10. As is known, the stem portion has a free end portion 11 which, in the embodiment shown, is pointed. The opposite end of the stem 10 is designated as a root end 12. A major part of the stem portion 10 is cylindric, the only deviation being at the pointed free end 11 where the shape is conical. A helical thread 13 projects from the surface of the stem portion 10. It extends from the pointed free end 11 and terminates at a root end portion 14 of the thread 13, which is spaced from the root end 12 of the stem 10.
The root end 12 of the stem 10 is integral with a minor base end 15 of a frustoconical portion 16. The diameter of the root end 12 is the same as that of the minor base portion 15. Thus, the frustoconical portion 16 projects axially from the root end 12 and is coaxial with the root end about a common axis 17 of the screw.
The opposite end of the frustoconical portion 16 is a major base end 18. In the embodiment shown, the major base end 18 coincides with, and thus has the same diameter as a first end 19 of a root cylindric portion 20. The portions 18, 19 are integral and co-axial with the axis 17 and with each other.
The other end 21 of the root cylindric portion 20 merges with a flat annular, downwardly facing underside 22 of a washer section 23 which is integral with the cylindric portion 20. The drawings show that the diameter B1 (FIG. 4) is a multiple of that B3 (FIG. 3) of the second cylindric portion 20.
The washer section 23 defines a flat, annular upper face section 24. It is parallel with and is turned away from the underside 22.
A centrally disposed, coaxial, shallowly convex head portion 25 projects upwardly from the upper face section 24. The head portion 25 is provided with centrally disposed drive tool engagement recess 26. The particular contour in plan of the recess is shown in FIG. 5. It is to be appreciated, however, that the specific type of the recess 26 is not a part of this invention and is optional. It has to be compatible with a predetermined tool for driving the screw into a base and preferably is suitable for use with a power tool when the screw is to be used in manufacturing furniture, wooden structures or other products where power screw driving tools are required.
Reference may now be had to the examples of different measurements of the described parts of the screws as diagrammatically shown in FIGS. 3 and 4.
While certain applications may require otherwise, it is generally preferred that the axial length A3 of the root cylindric portion 20 be smaller than its diameter B3 (FIG. 4) as this arrangement facilitates the application of the screw without the need of pre-drilling a bore in the workpiece.
Another preferred feature is that while the specific diameter B2 of the head 25 is of course, smaller than the diameter B1 of the washer section 23 it is larger than the diameter B3 of the root cylindric portion 20. The latter diameter B3 may be dictated by the size of bores in hardware with which the screw is to be used, for instance a hinge wing.
The shallowly convex shape of the head portion combines with the particular physical structure of the washer section 23 to provide a relatively smooth, graduated rising of the head portion of the screw above the surface of the workpiece without sudden high corners which might cause injury, for instance to animals in zoo structures. The term "shallowly" convex used to describe the head portion 25 designates the general condition where the ratio of the axial height A1 of the head portion 25 to its diameter B2 is in the range of about 0.2 to about 0.25, in other words, the axial height of the head portion 25 above the washer section 23 is generally less than about 1/4 of the diameter of the head portion 25 at the upper surface of the washer section 25. By the same token, it is preferred that the ratio of the thickness A2 of the washer section 23 to the axial height A1 of the head portion 25 be in the range of about 0.75 to about 0.9, in other words, the thickness A2 of the washer 23 smaller than the height A1 of the convex head portion 25.
With particular reference to FIGS. 3 and 4, the following Table 1 presents three examples of different embodiments of the screw of the present invention, having typical physical measurements of individual portions of the screw. The three embodiments shown are 6, 7 and 8 mm which roughly corresponds to 1/4"; 5/16" and 3/8" wood screws each having a total length of about 80 mm, respectively. The respective size particulars of the inventive screw, are described using reference characters of FIGS. 3 and 4.
TABLE 1______________________________________SIZE PARTICULARS OF THREE EMBODIMENTS OF THEINVENTIVE SCREW (in mm)Size of the screw 8 7 6______________________________________A1 Head 25 height 2.4 2 1.6A2 Washer 23 thickness range 1.8-1.5 1.6-1.3 1.4-1A3 Axial length of root cylinder 20 2 (max) 2 (max) 1.5 (max)A4 Axial length of frustocon, port. 16 2 (max) 2 (max) (1.5 max)B1 Diameter range of washer section 23 18.5-16 16.5-14 14-12.5B2 Diameter range of head portion 25 10.5-10 10-9.7 9-8.7B3 Diameter range of cylindric root 20 9.4-8.9 7.8-7.3 6.3-5.9B4 Outer dia. range of thread 13 8-7.5 7.2-6.7 6.2-5.7B5 Diameter range of stem portion 10 5.4-5.1 4.82-4.79 4.24-4.18______________________________________
It follows from the Table 1 that a wide range of screws according to the present invention can be produced.
The contrast between the smoothness of the head section 23-25 of the Inventive screw and an existing screw or bolt can be appreciated upon review of FIG. 2. The broken line shows diagrammatically the contour 27 of a comparable wood screw or bolt, having the same overall height and thus strength in torque. As is known, the head 27, has a relatively high side section 28 which may give rise to injuries. Another disadvantage is in that the relatively small surface area of the underside of the head 27 may result in excessive specific pressure detrimental to the surface of a wooden workpiece and also reducing the tightness of the fastening.
It has also been established that the screw of the present invention, manufactured within the above tolerances possesses torque strength which makes it suitable for use with power screw driving tools while utilizing a drive tool engagement cavity or recess 26. It is believed that this is due to an inventive feature whereby the length of the frustoconical portion 16 generally corresponds to that of the root cylindric portion 20.
Those skilled in the art will readily appreciate that various modifications can be made to the screw of the present invention departing from the structural particulars of the embodiments described, without departing from thescope of the present invention. Accordingly, we wish to protect by letters patent which may issue on this application all such embodiments as properly fall within the scope of our contribution to the art. | A screw, particularly a wood screw present a combination of a threaded cylindric stem (10) merging, over an inversely frustoconical part (16) with an enlarged diameter cylindric portion (20) which is integral with an underside of a large diameter washer section (23) which, in turn is integral with a shallowly convex head portion (25). The invention is intended for wood screws usually in the range of about 6 mm and provides a reduced chance of injury by providing a smooth merging with the flat surface on which the screw head is located. Also, the screw has an improved torque characteristics making it suitable for use with power screw driving tools. | 8 |
BACKGROUND OF THE INVENTION
The present invention concerns a composition for dispensing a toxic agent through the exhaust of an internal combustion engine, and a method for dispensing such a toxic agent. More particularly, the invention is concerned with a fuel composition containing a minor but effective amount of an insecticide or other toxic agent such as a fungicide or herbicide.
It is known to attempt to introduce an ingredient such as an insecticide into the exhaust pipe of an internal combustion engine operating a lawn mower or the like. It is also known to provide apparatus to create a fog or smog by combusting part of a mixture to provide heat to vaporize and dispense the balance of the mixture. The former concept is illustrated in U.S. Pat. Nos. 2,759,292 (Whipple et al); 2,865,671 (Jensen) and 3,205,176 (Tenney). Each of these patents provides apparatus for injecting an agent to be dispensed into the exhaust of an engine and provides means to overcome problems such as engine back pressure, control of feeding rate, etc.
The second mentioned concept, that of providing a fog, is illustrated in U.S. Pat. No. 2,402,402 (Hickman). Hickman discloses a composition including a minor amount of gasoline with a major amount of fuel oil and an insecticide, rotenone. The mixture is passed through the Hickman apparatus in which a vapor portion of it is combusted to vaporize the balance.
These prior art attempts involve the provision of separate apparatus to dispense the agent. Hickman is illustrative of a special apparatus required solely to carry out the creation and dispensing of a fog. The other patents are illustrative of the concept of providing auxiliary apparatus to inject an agent downstream of the combustion chamber of an engine for dispersal thereof by the engine exhaust.
It is an object of the present invention to provide a novel composition dispensable by an internal combustion engine of conventional design without necessity for any auxiliary equipment attached to the engine.
It is another object of the present invention to provide a novel method for dispensing a toxic agent by incorporating the agent into the fuel of an internal combustion engine and dispensing the agent as a part of the engine exhaust, the agent having passed through the combustion engine with the fuel.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a composition for dispensing a toxic agent through the exhaust of an internal combustion engine, the composition comprising a mixture of a minor amount of one or more organic toxic agents effective to control target pests with a major amount of internal combustion engine fuel. The proportion of fuel in the mixture is sufficient to enable operation of an internal combustion engine fueled thereby. The toxic agents are selected from the class consisting of insecticides, fumigants and herbicides which are soluble in the fuel and refractory to fuel combustion conditions of the fueled engine. The toxic agents are present in the mixture in an amount at least sufficient to provide, in the exhaust of the fueled engine, an amount of the toxic agent which is effective against such target pests.
Certain objects of the invention are attained when the fuel is gasoline and the toxic agent is an insecticide comprising either a halogenated hydrocarbon or an organophosphorous compound. The insecticide may be selected from aldrin, chlordane, dieldrin, DDT, heptachlor, malathion and mirex and be present in the amount of between about 21/2 % to 10% by weight of the mixture. Other objects of the invention are attained by a composition for dispensing an insecticide through the exhaust of an internal combustion engine, the composition comprising a mixture of a minor amount of one or more insecticides effective to control target insects, with a major amount of internal combustion engine fuel, the proportion of fuel in the mixture being sufficient to enable operation of an internal combustion engine fueled thereby. The insecticides are soluble in the fuel, refractory to fuel combustion conditions in the fueled engine and present in the mixture in an amount at least sufficient to provide, in the exhaust of the fueled engine, an amount of said insecticide which is effective against such target insects.
Certain objects of the invention are attained when the insecticide is malathion and is present in the amount of between about 21/2 % to 10% by weight of the mixture. The fuel may be a kerosene-gasoline mixture.
The invention also provides a method of dispensing a toxic agent over a ground area comprising supplying to an internal combustion engine operating a ground vehicle a fuel comprising a mixture of a minor amount of one or more organic toxic agents effective to control target pests with a major amount of internal combustion engine fuel. The proportion of fuel in the mixture is sufficient to enable operation of an internal combustion engine fueled thereby. The toxic agents are selected from the class consisting of insecticides, fumigants and herbicides which are soluble in the fuel and refractory to fuel combustion conditions of the fueled engine and the toxic agents are present in said mixture in an amount at least sufficient to provide in the exhaust of the fueled engine, an amount of the toxic agent which is effective against such target pests. The method includes a step of discharging engine exhaust from the fueled engine as it moves over the ground area into the atmosphere with the toxic agent depositing upon ground and foliage surfaces.
The step of supplying the mixture may comprise the step of supplying a mixture of a minor amount of an insecticide with a major amount of gasoline.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A fuel mixture for use in an internal combustion engine, in accordance with the invention, must enable operation of the engine notwithstanding the presence of a toxic agent in an amount sufficient to provide in the engine exhaust a concentration of the toxic agent which is effective against target pests.
Since the invention contemplates using a fuel composition containing a organic toxic agent, or otherwise introducing a toxic agent into the combustion chamber, i.e., the cylinders of an internal combustion engine, the toxic agent must be sufficiently refractory to survive passage through the firing chamber without being destroyed or rendered into an innocuous composition or one which is ineffective against the target pests.
Further, the toxic agent must be soluble in the fuel so as to pass through the engine, carburetor or other components without causing problems of blockage.
Generally, halogenated hydrocarbon compounds and organophosphorous compounds employed as insecticides meet the foregoing requirements when present in suitable amount in a hydrocarbon fuel for internal combustion engines.
As used herein and in the claims, the term "soluble" is intended to include liquid toxic agents which are miscible with a liquid hydrocarbon fuel, solids which are soluble in the fuel and solutions of solids or liquids in a carrier vehicle, which solutions are soluble in the fuel. Thus, for example, a liquid insecticide or a solution of an insecticide in a carrier liquid which is miscible with a gasoline fuel is deemed to be soluble in the fuel.
The fuel may be any convenient fuel for the internal combustion engine to be employed, such as a diesel fuel or gasoline. The gasoline may include other components such as the lubricating oils commonly mixed with gasoline intended for use in two-cycle gasoline engines.
"Gasoline" and "kerosene" as used herein have their usual and conventional meanings identifying hydrocarbon fuels employed as gasoline engine fuels, a lighting or heating fuel in gasoline or kerosene lanterns, stoves and the like. Gasoline is a relatively low boiling point fraction usually obtained, at least in part, by cracking of petroleum fractions. Kerosene is usually a somewhat higher boiling point fuel oil fraction of petroleum.
The toxic agent may be any suitable insecticide, fumigant or herbicide, including fungicides, etc.
Among the insecticides believed to be suitable for incorporation into a gasoline or gasoline-kerosene fuel mixture are the following halogenated hydrocarbon compounds: aldrin, chlordane, dieldrin, DDT, heptachlor, malathion and mirex.
Also suitable are organophosphorous compounds such as malathion. Other insecticides are also believed to be effective include halogenated hydrocarbons such as BHC, TDE, methoxychlor, toxaphene, CPCBS, CPBS, BPIPS, carbon tetrachloride, methyl bromide, ethylene dibromide, ethylene dichloride, tetrachloroethane and chloropicrin; and organophosphorous compounds such as TEPP, parthion, paraoxon, TPAM, schradan, dimefox, mipafox, systox and EPN.
The following table provides a chemical description of the foregoing identified insecticides:
Table I______________________________________ Common Name Chemical Name______________________________________A. Halogenated Hydrocarbon InsecticidesBHC, 1, 2, 3, 4, 5, 6 hexachlorocyclohexangamma--BHC (Benzene hexachloride), gamma-isomer thereof. Mixture ofDDT isomers of dichloro-diphenyl- trichloro ethane, usually predominantly pp'-DDT (1,1,1-Trichloro-2,2-di- (p-chlorophenyl)-ethane)TDE 1,1-Bis (p-chlorophenyl)- 2,2-dichloroethaneMirex (Dechlorane) Dodecachlorooctahydro-1, 3, 4, -metheno- 1H-cyclobuta [cd]-pentalene.Methoxychlor 1, 1, 1-Trichloro-2, 2-di-(4-methoxy- phenyl)-ethaneDieldrin Contains not less than 85% of 1, 2, 3, 4, 10, 10-hexachloro-6, 7-epoxy-1, 4, 4a, 5, 6, 7, 8, 8a-octahydro-1,4, 5, 8-dimethanonaphthalene, and not more than 15% of insecticidally active related compoundsAldrin Contains not less than 95% of 1, 2, 3, 4, 10, 10-hexachloro-1, 4, 4a, 5, 8, 8a- hexahydro-1, 4, 5, 8-dimethanonaphtha- lene, and not more than 5% of insec- ticidally active related compounds Chlorinated campheneToxaphene (67-69% chlorine)Heptachlor (Drinox) 74% 1, 4, 5, 6, 7, 8, 8a-heptachloro-3a, 4, 7a-tetrahydro-4, 7-methanoindeneChlordane 2, 3, 4, 5, 6, 7, 10, 10-Octachloro- 4, 7, 8, 9-tetrahydro-4, 7-endomethy- leneindanCPCBS 4-Chlorophenyl-4-chlorobenzene sulfonatePCPBS 4-Chlorophenylbenzene sulfonateBPIPS 2-(p-tert-Butylphenoxy)isopropyl 2- chloroethyl sulfiteCarbon tetrachloride Carbon tetrachlorideMethyl bromide Methyl bromideEthylene dibromide Ethylene dibromideEthylene dichloride Ethylene dichlorideTetrachloroethane TetrachloroethaneDD 1, 2-Dichloropropane, 1, 3-dichloro- propylene in approximately equal proportionsChloropicrin ChloropicrinB. Organophosphorus InsecticidesTEPP (HETP) Tetraethyl pyrophosphateParathion 0,0 Diethyl o, p-nitrphenyl thion phosphateParaoxon Diethyl-p-nitrophenyl phosphateTPAM Diethylthiophosphoric acid ester of 7- hydroxy-4-methylcoumarinMalathion 0,0 Dimethyl dithiophosphate of diethyl mercaptosuccinate [formerly known as S-(1, 2-dicarboxyethyl)-0,0-dimethyl dithiophosphate] Bisdimethyl-Schradan aminophosphonous anhydride or octamethylpyrophosphoramideDimefox Bis (dimethylamino) fluorophosphine oxideMipafox Bis (monoisopropylamino) fluorophosphine oxideSystox Diethylthiophosphoric ester of β-ethyl mercaptoethanol O-Ethyl o,EPN p-nitrophenyl benzene thiophosphate______________________________________
One composition in accordance with the invention successfully employed comprises a mixture of a gasoline fuel with a minor amount of the insecticide malathion. In a series of tests, mixtures containing from about 5% to 20% by volume of a 50% by weight solution of malathion in a gasoline and gasoline-kerosene fuel were employed in two different lawn mowers. The lawn mowers were operated for periods of about one and a half hours (the time necessary to empty a fuel tank) five times over a period of three months without apparent adverse effect upon the lawn mower engines.
The lawn mowers were employed at normal grass cutting intervals during the period July through September 1977 in Sarasota, Fla. The fuel compositions given in Table II below were employed in the various tests. In each case, visual observations of the effect of the exhaust from the engines on insects, including mosquitoes and other flying and crawling insects, were made. Close examination showed that insects were killed by the exhaust fumes, mosquitoes and several varieties of bugs being found dead in the treated area. Live insects were trapped and exposed to the exhaust fumes gathered in a plastic bag and were killed upon such exposure.
Operator observations comparing mowing the lawn with the same lawn mowers powered by gasoline fuels not containing a toxic agent showed that mosquitoes and bugs were not killed. This observation was reinforced by the fact that, when mowing with a conventional gasoline fuel, the operator was bitten by mosquitoes to a considerable extent but when employing a fuel mixture in accordance with the invention during similar hours and under similar conditions there was noticeably less mosquito activity, in fact, virtually none at all on the operator.
The following fuel compositions were employed in these tests in each of the following two lawn mowers, as shown in Table II.
Lawn mower A, a twenty-six inch rotary lawn mower powered by a 3.5 horsepower Briggs & Stratton four-cycle gasoline engine. Lawn mower B is a Bolens riding mower, model number 72,801, powered by a 7 horsepower four-cycle gasoline engine manufactured by Tecumseh-Lauson Engine and Power Products.
Table II______________________________________ The following mixtures were used in both -lawn mower A and lawn mowerB.Malathion Gasoline Kerosene% by Weight______________________________________10 15 7510 20 70 5 -- 9510 -- 9020 -- 80______________________________________
The fuel mixture was prepared in each case by premixing the indicated quantity of malathion with the gasoline or gasoline/kerosene fuel. The mixture was shaken and stirred thoroughly. The malathion was introduced into the mixture in the form of Malathion 50 Insect Spray sold under the trademark ORTHO by the Ortho Division of Chevron Chemical Company, San Francisco, Calif. The label gives the following ingredients:
Malathion--50% by weight;
Aromatic Petroleum Derivative Solvent--33% by weight;
Inert Ingredients--17% by weight.
The lawn mowers were operated in the normal manner without any indications of adverse effect due to the admixture of the insecticide with the fuel. While it is convenient and preferred to thus premix the toxic agent with the fuel, the method of the invention would allow for introducing the fuel and the toxic agent from separate tanks into the combustion chamber of the engine. However, since it is an advantage of the present invention to enable practice of the method without modification to existing equipment such as lawn mowers, cultivators or other agricultural combustion engine powered appliances, it is preferable to premix the toxic agent and fuel and to introduce the mixture of the invention into the conventional fuel tank of the device.
Obviously, any suitable toxic agent required for a specific purpose or purposes which is suitably soluble in the fuel and refractory may be employed. Thus, herbicides would include not only toxic agents designed to kill or control selected plants or weeds, but agents designed to kill or control fungi or other organisms which attack plants which it is desired to save. While a primary objective is to enable the dispensing of an insecticide to control insects, the invention is also applicable to dispensing fumigants or other agents to control other pests such as rodents or the like.
It is necessary that the toxic agent retain its desired qualities of effectiveness despite passing through the engine combustion chamber as mentioned previously and numerous toxic agents are capable of this despite the elevated temperature because of the very short residence time at the elevated temperature. In some cases, an advantage is derived by the intimate admixture of the toxic agent and the oil particles, etc. in the exhaust since this enhances persistence of the toxic agent. | A composition for dispensing toxic agents, such as an insecticide, comprises an internal combustion engine fuel containing a minor amount of an insecticide which is refractory to the fuel combustion conditions of the engine and soluble in the fuel. The proportion of insecticide in the mixture is low enough to enable operation of the engine to power a vehicle such as a lawn mower and high enough to be effective in the engine exhaust against target pests. In use, a gasoline fuel containing up to 10% by weight of malathion is employed to operate an internal combustion engine powering an implement such as a lawn mower and the insecticide is dispensed via the engine exhaust over the ground traversed by the implement. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation patent application of U.S. patent application Ser. No. 12/561,491 filed on Sep. 17, 2009 now U.S. Pat. No. 7,874,762, which is a continuation application of U.S. patent application Ser. No. 11/951,995 filed on Dec. 6, 2007 now abandoned, which is a divisional application of U.S. patent application Ser. No. 11/300,138 filed on Dec. 14, 2005 now abandoned, the entirety of the disclosures of which are expressly incorporated herein by reference.
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
Not Applicable
BACKGROUND
1. Technical Field
The present invention relates generally to the art of concrete construction. More particularly, the present invention relates to an apparatus for facilitating the placement of slip dowel rods within adjacent concrete slabs.
2. Related Art
In the concrete construction arts, “cold joints” between two or more poured concrete slabs are frequently used for the paving of sidewalks, driveways, roads, and flooring in buildings. Such cold joints frequently become uneven or buckled due to normal thermal expansion and contraction of the concrete and/or compaction of the aggregate caused by inadequate preparation prior to pouring of concrete. As a means of preventing bucking or angular displacement of such cold joints, it is common practice to insert smooth steel dowel rods generally known as “slip dowels” within the edge portions of adjoining concrete slabs in such a matter that the concrete slabs may slide freely along one or more of the slip dowels, permitting linear expansion and contraction of the slabs while also maintaining the slabs in a common plane and thus preventing undesirable bucking or unevenness of the cold joint.
In order to function effectively, slip dowels must be accurately positioned parallel within the adjoining concrete slabs. The non-parallel positioning of the dowels will prevent the desired slippage of the dowels and will defeat the purpose of the “slip dowel” application. Additionally, the individual dowels must be placed within one or both of the slabs in such a manner as to permit continual slippage or movement of the dowels within the cured concrete slab(s).
A number of methods of installing smooth slip dowels are popular. According to one method, a first concrete pour is made within a pre-existing form. After the first pour has cured, and edge of the form, usually a wooden stud, is stripped away. A series of holes are then drilled parallel into the first pour along the exposed edge from which the form has been removed. The depth and diameter of the individual holes varies depending on the application and the relative size of the concrete slabs to be supported. As a general rule, however, such holes are at least twelve inches deep and typically have a diameter of approximately five-eighths (⅝) of an inch.
After the parallel series of holes have been drilled into the first pour, smooth dowel rods are advanced into each hole such that one end of each dowel rod is positioned within the first pour and the remainder of each dowel rod is positioned within the first pour and the remainder of each dowel rod extends into an adjacent area where a second slab of concrete is to be poured. Thereafter, concrete is poured into such adjacent area and is permitted to set with the parallel aligned dowels extending thereto. After the second pour has cured, the slip dowels will be held firmly within the second slab, but will be permitted to slide longitudinally within the drilled holes of the first slab thereby accommodating longitudinal expansion and contraction of the two slabs while at the same time preventing buckling or angular movement therebetween.
Although the above-described “drilling method” of placing slip dowels is popular, it will be appreciated that such method is extremely labor intensive. In fact, it takes approximately ten minutes to drill a five eighths inch (⅝″) diameter by twelve inch long hole into the first pour and the drilling equipment, bits, accessories, and associated set up time tends to be very expensive. Moreover, the laborers who drill the holes and place the slip dowels must be adequately trained to ensure that the dowels are arranged perpendicular to the joint but parallel to one another so as to permit the desired slippage.
Another popular method of placing slip dowels involves the use of wax-treated cardboard sleeves positioned over one end of each individual dowel. According to such method, a series of holes are drilled through one edge of the concrete form and smooth dowels are advanced through each such hole. Thereafter, the treated cardboard sleeves are placed over one end of each dowel, with a first pour subsequently being made within the form which covers the ends of the dowels including the cardboard sleeves thereon. After the first pour has set, the previously drilled form is stripped away, leaving the individual dowels extending into a neighboring open space where the second pour is to be made. Subsequently, the second pour is made and cured. Thereafter, the slip dowels will be firmly held by the concrete of the second pour, but will be permitted to longitudinally slide against the inner surfaces of the wax treated cardboard sleeves within the first pour. Thus, the waxed cardboard sleeves facilitate longitudinal slippage of the dowels, while at the same time holding the two concrete slabs in a common plane, and preventing undesirable buckling or angular movement thereof.
This method was also associated with numerous deficiencies, namely, that after the first pour was made, the free ends of the dowels were likely to project as much as eighteen inches through the form and into the open space allowed for the second pour. Because the drilled section of the form must be advanced over those exposed sections of dowel to accomplish stripping or removal of the form, it is not infrequent for the exposed portions of the dowels to become bent and, thus, non-parallel. Additionally, the drilled section of the form became damaged or broken during the removal process, thereby precluding its reuse.
Each of the above described known methods of placing slip dowels between concrete slabs often results in the dowels being finally positioned at various angles rather than in the desired parallel array. Therefore, the necessary slippage of the dowels is impeded or prevented.
In response to such deficiencies in the art, a number of dowel placement sleeves have been developed. One such development is U.S. Pat. No. 5,005,331 to Shaw, et al., which is wholly incorporated by reference herein, teaches a slip dowel positioning device that is extractable from the first concrete slab. The device is comprised of a hollow cylindrical portion with a flange or gusset extending perpendicularly therefrom. The flange permitted the device to be attached to the form, and upon curing, the form was removed, thereby also removing the positioning device. Thereafter, a smooth dowel was inserted in the cavity formed in the space previously occupied by the positioning device, and a subsequent slab of concrete was poured. One of the deficiencies associated with the '331 device was that it was required to be removed from a cured slab of concrete, necessitating extra force during removal. Further, the configuration which enabled the positioning device to be removable resulted in a cavity which was less than ideal, in that slight discrepancies in the angular displacement of the smooth dowel are introduced. Therefore, slip dowel placement which was truly parallel to the concrete surface is not possible.
Thus, alternatively, the '331 patent and additionally U.S. Pat. No. 5,216,862 to Shaw, et al., which is also incorporated by reference wherein, contemplated a positioning device which remained in the concrete slab. The positioning device was attached to the form via staples or small nail heads, and forcibly stripped upon curing of the first slab of concrete. However, the requirement of forcibly removing the form from the positioning device remained.
Accordingly there is a need in the art for an inexpensive and readily reproducible dowel positioning device which can remain in the concrete slab after curing. Further, there is a need for a dowel positioning device which can be attached and removed from a form with minimal force and a minimum number of extraneous components. These needs and more are accomplished with the present novel and inventive device, the details of which are discussed more fully hereunder.
BRIEF SUMMARY
In light of the foregoing problems and limitations, the present invention was conceived. In accordance with one embodiment of the present invention, provided is a concrete dowel placement device for attachment to a form. More particularly, the device comprises a stud having a generally tubular body, a proximal stud end and a distal stud end, and a cover having a generally tubular body having an outer cover surface, an open proximal cover end, a closed distal cover end, and a hollow cover interior compartment extending axially therein configured to slidably receive the stud. In one embodiment, the stud is of uniform construction and has a form insertion section disposed towards the proximal stud end and encompassed by the form, and a cover insertion section disposed towards the distal stud end and encompassed by the cover. The form insertion section extends beyond the proximal cover end when the cover is placed on the stud. Furthermore, the form insertion section is tapered to a point defining the proximal stud end for ease in driving the stud into the form. Alternatively, the form insertion section is threaded and tapered to a point defined by the proximal stud end for screwing the stud into the form. In order to enable the stud to be screwed into the form, the distal stud end defines a molded surface configured to cooperate with a screwdriver head.
In accordance with another embodiment of the present invention, the distal stud end and the proximal stud end each have an opening and a hollow stud interior compartment extending axially therebetween. The stud is configured to slidably receive a nail having a length greater than that of the hollow stud interior compartment, the nail having a head in an abutting relationship with the distal stud end and a point driven into the form. In another embodiment, the stud is configured to receive a threaded screw having a length greater than that of the hollow stud interior compartment, with the screw having a head in an abutting relationship with the distal stud end and a point screwed into the form. Further, the stud may include threading disposed in the hollow stud interior compartment to cooperatively retain the threaded screw.
According to yet another aspect of the present invention, the cover includes an integrated flange on the proximal cover end. Preferably, the cover is formed of plastic, and the stud is ¼ inch in diameter. Along these lines, the hollow stud interior compartment is also ¼ in diameter.
In accordance with still another aspect of the present invention, disclosed is a method for forming a cold joint between adjoining sequentially formed slabs of concrete. The method is comprised of a) securing one or more studs to one or more forms; b) attaching a cover on to a respective one of the studs; c) forming a first enclosed area with the forms; d) pouring a first slab of concrete into the first enclosed area; e) curing the first slab of concrete; f) slidably removing the forms from the slab of concrete thereby concurrently withdrawing the studs from the covers, wherein the covers remains within the first slab of concrete; g) inserting a dowel into each of the covers remaining in the first slab of concrete; h) attaching a cover on to respective ones of the studs on the form; i) forming a second enclosed area adjacent to the first slab of concrete with the forms, wherein at least a part of the second enclosed area is defined by an edge of the first concrete slab and at least one of the dowels extend into the second enclosed area; j) pouring a second slab of concrete into the second enclosed area; and k) curing the second slab of concrete. The dowel is generally cylindrical, and may be constructed of stainless steel, while the covers are constructed of plastic.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:
FIG. 1 a is a perspective view of a first embodiment of a stud and a speed cover in accordance with an aspect of the present invention;
FIG. 1 b is a side view of a first embodiment of a speed cover attached to a stud which is inserted into a form;
FIG. 2 a is an exploded perspective view of a second embodiment of a stud having an open distal and proximal ends with a nail to be inserted therethrough and a speed cover;
FIG. 2 b is a side view of a second embodiment of a speed cover attached to a stud secured by a conventional nail which is inserted into a form;
FIG. 3 a is an exploded perspective view of a third embodiment of a stud having an open distal and proximal ends with a screw to be inserted therethrough and a speed cover;
FIG. 3 b is a side view of a third embodiment of a speed cover attached to a stud secured by a conventional screw which is inserted into a form;
FIG. 4 is a perspective view of a plurality of forms defining an enclosed area;
FIG. 5 is a perspective view of a first slab of concrete surrounded by a plurality of forms, with one form being removed from the concrete;
FIG. 6 is a perspective view of a first slab of concrete with speed covers within, and the placement of dowels;
FIG. 7 is a perspective view of a first slab of concrete with speed covers within and dowels extending into a second enclosed area defined by an edge of the first slab of concrete and a plurality of forms;
FIG. 8 is a perspective view of a first and second slab of concrete supported by a plurality of speed covers and dowels within respective concrete slabs; and
FIG. 9 is a side view of a first and second slab of concrete supported by a speed cover and a dowel within respective concrete slabs.
DETAILED DESCRIPTION
The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and the sequence of steps for developing and operating the invention in connection with the illustrated embodiment. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. It is further understood that the use of relational terms such as first and second, and the like are used solely to distinguish one from another entity without necessarily requiring or implying any actual such relationship or order between such entities.
With reference now to the figures, specifically FIG. 1 a and FIG. 1 b , a first embodiment of the present inventive dowel device with a closed end speed cover is shown. A form 30 , which by way of example only and not of limitation, is constructed of wood or any other material well known in the art capable of rigidly defining an enclosed area, and capable of receiving and retaining a fastener such as a stud 20 , a nail 140 as illustrated in FIG. 2 a or a screw 240 as illustrated in FIG. 3 a . Still referring to FIG. 1 a and FIG. 1 b , according to a first embodiment of the present invention, the stud 20 includes a tapered section 26 , which tapers to define a sharp point disposed at a proximal end 24 , a shaft portion 28 , and a distal end 22 . The proximal end 24 is inserted or driven into the form 30 , and is frictionally retained therein. As will be appreciated by one having ordinary skill in the art, the tapered section 26 enables the stud 20 to be driven into the form 30 with a lesser amount of force. The stud 20 is typically a quarter-inch (¼″) in diameter, and may he constructed of any suitable material such as steel, stainless steel, or other metals having sufficient strength to prevent deformation of the stud 20 upon driving the same into the form 30 .
After driving the stud 20 into the form 30 , a speed cover 10 is placed on the stud 20 , covering the exposed part of a shaft portion 28 , i.e., the portion not encompassed by the form 30 . The speed cover 10 is defined by a tubular body 12 , a closed distal end 14 , and an open proximal end 16 , and includes an interior compartment 18 which extends axially from an interior distal end surface 19 through a tubular body 12 to the open proximal end 16 . The diameter of the interior compartment 18 is sufficient to enable a sliding relationship between the speed cover 10 and stud 20 . While the preferred configuration is for the distal end 22 of the stud 20 to be in an abutting relationship with the interior distal end surface 19 , and the open proximal end 16 to be in an abutting relationship with the form 30 , strict adherence to this configuration is not necessary. For example, the stud 20 may be inserted further into the form 30 , leaving a slight gap between the distal end 22 of the stud 20 and the interior distal end surface 19 of the speed cover 10 when it is positioned on the stud 20 . Preferably, though not necessarily, the proximal end 16 additionally defines a flange 11 extending arcuately about the speed cover 10 . Further, the speed cover 10 may be integrally formed of a plastic material fabricated by conventional molding techniques.
In a second embodiment shown in FIGS. 2 a and 2 b , a sleeve stud 120 has an open distal end 123 , with an interior compartment 129 extending therethrough. An open proximal end 124 is in an abutting relationship with the form 30 , and a conventional nail 140 having a nail point 143 and a nail head 142 is inserted through the interior compartment 129 and driven through the form 30 . The diameter of the interior compartment 129 is larger than that of the nail 140 , thereby enabling a sliding relation between the sleeve stud 120 and the nail 140 , while smaller than that of the nail head 140 to prevent the sleeve stud 120 from being withdrawn from the nail 140 once inserted. The diameter of the sleeve stud 120 is typically quarter-inch (¼″) and may be constructed of metal or other suitable material. Like the aforementioned first embodiment, the speed cover 10 includes a tubular body 12 , an interior compartment 18 , a closed distal end 14 , and an open proximal end 16 , through which the sleeve stud 120 may be inserted. The proximal end 16 is preferably in an abutting relation to the form 30 once placed on to the stud 120 . Additionally, the proximal end 16 may also define the flange 11 .
Referring now to FIGS. 3 a and 3 b , a third embodiment of the present invention is shown, with the sleeve stud 120 having the open proximal end 124 , the open distal end 123 , and the interior compartment 129 extending therebetween. Instead of a nail as in the second embodiment, a screw 240 having a screw point 243 and a screw head 242 is provided. The screw 240 is inserted through the sleeve stud 120 , and screwed or threaded through the form 30 . The screw head 242 preferably includes molding that cooperates with a screwdriver head. Such screw heads include standard Phillips heads, flatheads, hexagonal heads, or any other like configuration well known in the art. Optionally, the screw 240 may be integrally formed with the sleeve stud 120 to eliminate the manual step of inserting the screw 240 through the sleeve stud 120 . As in the previously mentioned first and second embodiments, the speed cover 10 has the open proximal end 16 , the closed distal end 14 , and the interior compartment 18 which is in a sliding relationship with the sleeve stud 120 . Further, the speed cover 10 may be integrally formed of a molded plastic, and may include the flange 11 extending from the speed cover 10 in an arcuate fashion. In general, it is to be understood that any fastening mechanism having an elongate structure with a head or other like feature which directly or indirectly cooperates with the stud 120 to attach the same to form 30 is understood to be encompassed by the present invention.
While reference has been made to the “stud” 20 as in FIGS. 1 a and 1 b , and to the “sleeve stud” 120 as in FIGS. 2 a , 2 b , 3 a , and 3 b , it will be understood that with regard to the relationship to the speed cover 10 , both “stud” 20 and “sleeve stud” 120 include an elongate entity which interfaces with the interior compartment 18 . As used henceforth in describing the formation of a concrete structure, the two terms may be readily interchanged. Further, it is also to be understood that the diameter of studs 20 and sleeve stud 120 are substantially the same as that of a dowel to be used to rigidify the cold joint between a first pour and a second pour of concrete.
With reference now to FIG. 4 , four forms 30 are arranged in a quadrangular configuration, forming a first enclosed area 310 . While FIG. 4 illustrates a quadrangular configuration, it is to be understood that the first enclosed area 310 can be any shape capable of being formed using conventional techniques well known in the art. As will be appreciated, a desired surface is excavated and a base course 305 comprised of larger-sized aggregate is formed prior to forming the first enclosed area 310 .
As set forth above, preferably each of the forms 30 , or at least one of the forms 30 , have the stud 20 centrally attached thereto by any of the described embodiments, including a unitary stud 20 which includes a tapered section for insertion into the forms 30 , a separate screw/hollow stud combination or the nail/hollow stud combination. The number of the studs 20 attached varies according to the needs of each application, and the proper distribution and spacing will be readily determined by a person having ordinary skill in the art. Further, each of the studs 20 have attached thereto the cover 10 as set forth above. As the height of the forms 30 defines the height of the ultimate concrete structure formed thereby since concrete is poured to be flush with the upper surface of the same, preferably the studs 20 are inserted in the longitudinal center of forms 30 to maximize the compressive strength of the concrete. Typically, the forms 30 are dimensional lumber such as a two-by-four, which is nominally two inches by four inches (2″ by 4″), but can be as small as one and a half inches by three and a half inches (1½″ by 3½″).
Still referring to FIG. 4 , and now, additionally to FIG. 1 a , upon forming an enclosed area 310 on top of a base course 305 in the desired configuration, a slab of concrete 300 is poured therein. Although any well known paving material may be used, concrete comprised of Portland cement and a mineral aggregate such as gravel or sand is preferred. As is understood, concrete is liquid in form before curing, and after pouring, the cement begins to hydrate and glue the aggregate and the cement together, forming a rock-like material. Thus, the outer surface of the speed cover 10 forms a bond with the surrounding concrete slab 300 , and remains embedded therein. Since the proximal end 16 of speed cover 10 abuts the form 30 , and therefore the edge of the concrete slab 300 , the interior compartment 18 does not fill with concrete and remains exposed to the exterior of concrete slab 300 . The occupation of the interior compartment 18 by the stud 20 further reduces the tendency of concrete to flow inside speed covers 10 .
Now referring to FIG. 5 , shown is the first cured slab of concrete 300 , with the form 30 being removed. Along with the form 30 , also removed are the studs 20 previously embedded within the speed cover 10 . As a result of the sliding relation, the studs 20 are easily and quickly removed from the speed covers 10 . As illustrated, the speed covers 10 remains in the cured slab of concrete 300 , and the open proximal end 16 of the speed covers 10 forms an edge of the cured slab of concrete 300 . Further, a cavity within the cured slab of concrete 300 is effectively defined by the interior compartment 18 of the speed covers 10 .
Referring to FIG. 6 , metallic dowels 80 are inserted into the interior compartment 18 of each of the speed covers 10 embedded within the first cured concrete slab 300 . Essentially, the speed covers 10 eliminate the error-prone drilling step in previously known methods of forming cavities for inserting dowels to brace “cold joints” between two sequentially poured slabs of concrete. The metallic dowels are preferably quarter inch (¼″) in diameter, and constructed of stainless steel. As a person of ordinary skill in the art will recognize, a smaller diameter stainless steel dowel possesses the same sheer strength characteristics as that of a larger diameter mild steel dowel. For example, a quarter-inch (¼″) stainless steel dowel has the same sheer strength as that of a half-inch (½″) mild steel dowel. Preferably, the metallic dowels 80 extend fully into speed cover 10 , and extend a substantial distance out of the same.
With reference now to FIG. 7 , a second enclosed area 410 is constructed with the forms 30 , with at least one edge defined by the first concrete slab 300 with the metallic dowels 80 extending therefrom. If another slab of concrete in addition to the one formed by the second enclosed area 410 is desired, the forms 30 will again include one or more studs 20 inserted thereon, and one or more covers 10 placed on the studs 20 . A second slab of concrete 400 is poured into the second enclosed area 410 , and is allowed to cure. In this fashion, a cold joint between the first slab of concrete 300 and the second slab of concrete 400 is formed.
As illustrated in FIGS. 8 and 9 , the exposed metallic dowels 80 is embedded within the second slab of concrete 400 , and extends into the first slab of concrete 300 via the speed cover 10 . With steel having substantially the same coefficient of thermal expansion as concrete, during temperature shifts the first slab of concrete 300 is permitted to expand and contract about the second slab of concrete 400 and vice versa along axis X of the metallic dowel 80 . Further, the aforementioned molded plastic construction of the speed cover 10 enable the first and the second concrete slabs 300 and 400 , respectively, to expand and contract a limited amount along the Z and Y axes. As a person of ordinary skill in the art will recognize, however, metallic dowel 80 is configured to significantly reduce such transformations. Thus, while the flexible characteristics of the speed cover 10 enable miniscule adjustments, large expansions and contractions are diminished by the placement of the metallic dowel 80 .
The particulars shown herein are by way of example and for purposes of illustrative discussion of the 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 present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice. | Disclosed are a concrete dowel placement devices and a method of utilizing the same. A metallic stud is driven, screwed, or otherwise attached to a form. The stud may be a unitary structure, or may be a hollow tube with conventional fastening means such as nails and screws extending through and holding the hollow tube to the form. A cover having an interior compartment substantially equal in diameter to the stud is slidably placed thereon, and a first enclosed area is developed with a plurality of forms. Concrete is poured into the first enclosed area, and upon curing, the form and the stud are removed, leaving the cover embedded in the concrete. A metallic dowel is inserted into the cover, and a second enclosed area is developed with like configured forms. The metallic dowel extends into the second enclosed area. Upon pouring concrete into the second enclosed area, a cold joint is formed between the concrete of the first enclosed area and the concrete of the second enclosed area, supported and braced by the metallic dowel. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 10/926,148, filed Aug. 25, 2004 now U.S Pat. No. 7,074,890; which application is a continuation of U.S. application Ser. No. 10/226,428, filed Aug. 23, 2002 (now U.S. Pat. No. 6,979,723); which application claims the benefit of U.S. Provisional Application No. 60/314,831, filed on Aug. 24, 2001; the entire disclosures of which are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to novel processes for preparing derivatives of glycopeptide antibiotics. More specifically, this invention is directed to multi-step processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain, the first two steps being conducted in a single reaction vessel without isolation of the intermediate reaction products.
2. Background
Glycopeptides (e.g. dalbaheptides) are a well-known class of antibiotics produced by various microorganisms (see Glycopeptide Antibiotics , edited by R. Nagarajan, Marcel Dekker, Inc. New York (1994)). Many synthetic derivatives of such glycopeptides are also known in the art and these derivatives are typically reported to have improved properties relative to the naturally-occurring glycopeptides, including enhanced antibacterial activity. For example, U.S. patent application Ser. No. 09/847,042, filed May 1, 2001, describes various glycopeptide phosphonate derivatives, some of which contain an amino-containing side chain. Such phosphate derivatives are particularly useful as antibiotics for treating gram-positive infections.
Accordingly, a need exists for new efficient processes which are useful for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain.
SUMMARY OF THE INVENTION
The present invention provides novel processes for preparing phosphonate derivatives of glycopeptide antibiotics having an amino-containing side chain. Among other advantages, the first two steps of the present process are conducted in a single reaction vessel without isolation of the intermediate reaction products, thereby generating less waste and improving the overall efficiency and yield of the process compared to previous processes.
Specifically, in one of its aspects, this invention is directed to a process for preparing a compound of formula 1:
wherein
R 1 is selected from the group consisting of C 1-10 alkylene, C 2-10 alkenylene and C 2-10 alkynylene;
R 2 is selected from the group consisting of C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic, —R a -Cy 1 , —R a —Ar 1 —Ar 2 , —R a —Ar 1 —R b —Ar 2 , —R a —Ar 1 —O—R b —Ar 2 ;
R 4 is C 1-10 alkylene;
R a is selected from the group consisting of C 1-10 alkylene, C 1-10 alkenylene and C 1-10 alkynylene;
R b is selected from the group consisting of C 1-6 alkylene, C 1-6 alkenylene and C 1-6 alkynylene;
Cy 1 is selected from the group consisting of C 3-8 cycloalkyl, C 5-8 cycloalkenyl, C 6-10 aryl, C 2-9 heteroaryl, C 2-9 heterocyclic;
Ar 1 and Ar 2 are independently selected from C 6-10 aryl and C 2-9 heteroaryl;
wherein each aryl, heteroaryl and heterocyclic group is optionally substituted with 1 to 3 substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, halo, hydroxy, nitro and trifluoromethyl, and each heteroaryl and heterocyclic group contains from 1 to 3 heteroatoms selected from nitrogen, oxygen or sulfur;
or a salt thereof;
the process comprising:
(a) reacting vancomycin or a salt thereof, with a compound of formula II:
wherein R 1 and R 2 are as defined herein; and R 3 is a amine-labile protecting group; and a reducing agent to form a compound of formula III:
wherein R 1 , R 2 and R 3 are as defined herein or a salt thereof;
(b) reacting the compound of formula III with an amine to provide a compound of formula IV:
wherein R 1 and R 2 are as defined herein, or a salt thereof; wherein step (a) and step (b) are conducted in the same reaction mixture without isolation of the intermediate from step (a); and
(c) reacting the compound of formula IV with formaldehyde and a compound of formula V:
in the presence of a base to provide a compound of formula I, or a salt thereof.
In the above process, R 1 is preferably C 1-6 alkylene. More preferably, R 1 is C 1-2 alkylene. Still more preferably, R 1 is —CH 2 —.
R 2 is preferably C 6-14 alkyl. More preferably, R 2 is C 8-12 alkyl. Still more preferably, R 2 is n-decyl.
In the process of this invention, R 3 is an amino-protecting group which is removed by treatment with an amine (i.e., a nucleophilic amine). Preferably, R 3 is a group of formula (A):
W—OC(O)— (A)
wherein W is selected from the group consisting of 9-fluorenylmethyl, 3-indenylmethyl, benz[f]inden-3-ylmethyl, 17-tetrabenzo[a,c,g,i]fluorenylmethyl, 2,7-di-tert-butyl[9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanthyl)]methyl, 1,1-dioxobenzo[b]thiophene-2-ylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo.
Preferably, W is 9-fluorenylmethyl, wherein the 9-fluorenylmethyl group is optionally substituted with 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, halo, nitro and sulfo. More preferably, W is 9-fluorenylmethyl.
Preferably, R 4 is C 1-6 alkylene. More preferably, R 4 is C 1-4 alkylene. Still more preferably, R 4 is —CH 2 —.
In step (a), the reducing agent is preferably an amine/borane complex. More preferably, the reducing agent is pyridine/borane or tert-butylamine/borane; and still more preferably, the reducing agent is tert-butylamine/borane.
In a preferred embodiment of this process, step (a) comprises the steps of:
(i) combining vancomycin or a salt thereof with a compound of formula II in the presence of base to form a reaction mixture;
(ii) acidifying the reaction mixture from step (i) with an acid; and
(iii) contacting the reaction mixture from step (ii) with a reducing agent.
In this preferred embodiment, the base in step (i) is preferably a tertiary amine; more preferably, the base is diisopropylethylamine.
Preferably, the acid employed in step (ii) is trifluoroacetic acid or acetic acid.
In step (b), the amine employed is preferably ammonium hydroxide or a primary amine. More preferably, the amine is ammonium hydroxide, methylamine or tert-butylamine; and still more preferably, the amine is tert-butylamine.
In step (c), the base employed is preferably a tertiary amine. Preferably, the tertiary amine employed is diisopropylethylamine. In a preferred embodiment, the molar ratio of tertiary amine to compound of formula V is about 3:1 to about 5:1; more preferably, about 4:1.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to novel processes for preparing glycopeptide phosphonate derivatives having an amino-containing side chain. When describing such processes, the following terms have the following meanings, unless otherwise indicated.
DEFINITIONS
The term “alkyl” refers to a monovalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkyl groups typically contain from 1 to 20 carbon atoms. Representative alkyl groups include, by way of example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like.
The term “alkenyl” refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds. Unless otherwise defined, such alkenyl groups typically contain from 2 to 20 carbon atoms. Representative alkenyl groups include, by way of example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, n-hex-3-enyl and the like.
The term “alkynyl” refers to a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds. Unless otherwise defined, such alkynyl groups typically contain from 2 to 20 carbon atoms. Representative alkynyl groups include, by way of example, ethynyl, n-propynyl, n-but-2-ynyl, n-hex-3-ynyl and the like.
The term “alkylene” refers to a divalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkylene groups typically contain from 1 to 10 carbon atoms. Representative alkylene groups include, by way of example, methylene, ethane-1,2-diyl (“ethylene”), propane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and the like.
The term “alkenylene” refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds. Unless otherwise defined, such alkenylene groups typically contain from 2 to 10 carbon atoms. Representative alkenylene groups include, by way of example, ethene-1,2-diyl, prop-1-ene-1,2-diyl, prop-1-ene-1,3-diyl, but-2-ene-1,4-diyl, and the like.
The term “alkynylene” refers to a divalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds. Unless otherwise defined, such alkynylene groups typically contain from 2 to 10 carbon atoms. Representative alkynylene groups include, by way of example, ethyne-1,2-diyl, prop-1-yne-1,2-diyl, prop-1-yne-1,3-diyl, but-2-yne-1,4diyl, and the like.
The term “alkoxy” refers to a group of the formula —O—R, where R is alkyl as defined herein. Representative alkoxy groups include, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy and the like.
The term “aryl” refers to a monovalent aromatic hydrocarbon having a single ring (i.e., phenyl) or fused rings (i.e., naphthalene). Unless otherwise defined, such aryl groups typically contain from 6 to 10 carbon ring atoms. Representative aryl groups include, by way of example, phenyl and naphthalene-1-yl, naphthalene-2-yl, and the like.
The term “cycloalkyl” refers to a monovalent saturated carbocyclic hydrocarbon group. Unless otherwise defined, such cycloalkyl groups typically contain from 3 to 10 carbon atoms. Representative cycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.
The term “cycloalkenyl” refers to a monovalent unsaturated carbocyclic hydrocarbon group having at least one carbon-carbon double bond in the carbocyclic ring. Unless otherwise defined, such cycloalkenyl groups typically contain from 5 to 10 carbon atoms. Representative cycloalkenyl groups include, by way of example, cyclopent-3-en-1-yl, cyclohex-1-en-1-yl and the like.
The term “halo” refers to fluoro, chloro, bromo and iodo; preferably, chloro, bromo and iodo.
The term “heteroaryl” refers to a monovalent aromatic group having a single ring or two fused rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heteroaryl groups typically contain from 5 to 10 total ring atoms. Representative heteroaryl groups include, by way of example, monovalent species of pyrrole, imidazole, thiazole, oxazole, fur, thiophene, triazole, pyrazole, isoxazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, indole, benzofuran, benzothiophene, benzimidazole, benzthiazole, quinoline, isoquinoline, quinazoline, quinoxaline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.
The term “heterocycle” or “heterocyclic” refers to a monovalent saturated or unsaturated (non-aromatic) group having a single ring or multiple condensed rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heterocyclic groups typically contain from 2 to 9 total ring atoms. Representative heterocyclic groups include, by way of example, monovalent species of pyrrolidine, imidazolidine, pyrazolidine, piperidine, 1,4-dioxane, morpholine, thiomorpholine, piperazine, 3-pyrroline and the like, where the point of attachment is at any available carbon or nitrogen ring atom.
The term “vancomycin” is used herein in its art recognized manner to refer to the glycopeptide antibiotic known as vancomycin. See, for example, R. Nagarajan, “Glycopeptide Anitibiotics”, Marcel Dekker, Inc. (1994) and references cited therein. The designation “N van -” refers to substitution at the vancosamine nitrogen atom of vancomycin. This position is also referred to as the N3″ position of vancomycin. Additionally, using a conventional vancomycin numbering system, the designation “29-” refers to the carbon atom position between the two hydroxyl groups on the phenyl ring of amino acid 7 (AA-7). This position is also sometimes referred to as the “7d” or the “resorcinol position” of vancomycin.
The term “salt” when used in conjunction with a compound referred to herein refers to a salt of the compound derived from an inorganic or organic base or from an inorganic or organic acid. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc and the like. Particularly preferred are ammonium, calcium, magnesium, potassium and sodium salts. Salts derived from organic bases include salts of primary, secondary and tertiary amines, including substituted amines, cyclic amines, naturally occuring amines and the like, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperadine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine and the like. Salts derived from acids include acetic, ascorbic, benzenesulfonic, benzoic, camphosulfonic, citric, ethanesulfonic, fumaric, gluconic, glucoronic, glutamic, hippuric, hydrobromic, hydrochloric, isethionic, lactic, lactobionic, maleic, malic, mandelic, methanesulfonic, mucic, naphthalenesulfonic, nicotinic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric and tartaric acids.
The term “protecting group” or “blocking group” refers to a group which, when covalently attached to a function group such as an amino, hydroxyl, thiol, carboxyl, carbonyl and the like, prevents the functional group from undergoing undesired reactions but which permits the function group to be regenerated (i.e., deprotected or unblocked) upon treatment of the protecting group with a suitable reagent. Representative protecting groups are disclosed, for example, in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis” 3rd Ed., 1999, John Wiley and Sons, N.Y.
The term “amine-labile protecting group” refers to a protecting group which is removed upon treatment with a suitable amine.
Process Conditions
The process of the present invention is conducted in three steps beginning with vancomycin or a salt thereof. The first step of the process is a reductive alkylation step which involves first combining one equivalent of vancomycin or a salt thereof, with one or more equivalents of an aldehyde of formula II:
wherein R 1 , R 2 and R 3 are as defined herein to form a imine and/or hemiaminal intermediate in situ.
The aldehydes of formula II employed in the process of the present invention are well-known in the art and are either commercially available or can be prepared by conventional procedures using commercially available starting materials and conventional reagents. For example, see WO 00/39156, published on Jul. 6, 2000, which describes various methods for preparing such aldehydes.
Typically, the vancomycin or a salt thereof and the aldehyde are combined in an inert diluent in the presence of an excess amount of a suitable base to form a reaction mixture. Preferably, the inert diluent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, acetonitrile/water, and the like or mixtures thereof Preferably, from about 1 to about 2 equivalents of the aldehyde are employed; more preferably, about 1.1 to about 1.2 equivalents. In this reaction mixture, a mixture of imines and/or hemiaminals is believed to be formed between the aldehyde and the basic nitrogen atoms of vancomycin, i.e., the vancosamine nitrogen atom and the N-terminal (leucinyl) nitrogen atom.
Formation of the imine and/or hemiaminal intermediate is typically conducted at a temperature ranging from about 0° C. to about 75° C., preferably at ambient temperature (i.e., about 20-25° C.) for about 1 to about 24 hours, preferably for about 6 to 12 hours, or until formation of the imine and/or hemiaminal is substantially complete.
Any suitable base may be employed to neutralize the vancomycin salt and to facilitate formation of the imine and/or hemiaminal, including organic bases, such as amines, alkali metal carboxylate salt (ire., sodium acetate and the like) and inorganic bases, such as alkali metal carbonates (i.e., lithium carbonate, potassium carbonate and the like). Preferably, the base is a tertiary amine including, by way of illustration, triethylamine, diisopropylethylamine, N-methylmorpholine, and the like. A preferred base is diisopropylethylamine. The base is typically employed in a molar excess relative to vancomycin. Preferably, the base is used in an amount ranging from about 1.5 to about 3 equivalents based on vancomycin; more preferably, about 1.8 to 2.2 equivalents.
When formation of the imine and/or hemiaminal mixture is substantially complete, the reaction mixture is acidified with an excess of acid. Any suitable acid may be employed including, by way of illustration, carboxylic acids (e.g. acetic acid, trichloroacetic acid, citric acid, formic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid and the like), mineral acids (e.g. hydrochloric acid, sulfuric acid, or phosphoric acid), and the like. Preferably, the acid is trifluoroacetic acid or acetic acid. The acid is typically added in a molar excess relative to vancomycin (and the base). Preferably, the acid is used in an amount ranging from about 3 to about 6 equivalents based on vancomycin; more preferably, about 3.5 to 5.5 equivalents.
While not wishing to be limited by theory, it is believed that the acid selectively hydrolyzes the imine and/or hemiaminal formed at the N-terminal amine of vancomycin in preference to the imine and/or hemiaminal formed at the vancosamine nitrogen atom. Acidification of the reaction mixture is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.25 to about 2.0 hours, preferably for about 0.5 to about 1.5 hours. Preferably, a polar, protic solvent is added during this step including, by way of example, methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, and the like. Alternatively, a mixed polar protic/non-protic solvent may be used, such as methanol/tetrahydrofuran, methanol/1,2-dimethoxyethane and the like
After acidification, the reaction mixture is contacted with a reducing agent to reduce the imine and/or hemiaminal. Any suitable reducing agent can be employed which is compatible with the functionality present in the glycopeptide. For example, suitable reducing agents include sodium borohydride, sodium cyanoborohydride, zinc borohydride, sodium triacetoxyborohydride, pyridine/borane, tert-butylamine/borane, N-methylmorpholine/borane, ammonia/borane, dimethylamine/borane, triethylamine/borane, trimethylamine/borane, and the like. Preferred reducing agents are amine/borane complexes such as pyridine/borane and tert-butylamine/borane.
The reduction phase of the reaction is typically conducted at a temperature ranging from about 0° C. to about 30° C., preferably at about 25° C., for about 0.5 to about 24 hours, preferably for about 1 to about 6 hours, or until the reduction is substantially complete. Preferably, a polar, protic solvent is present during this reduction step. The polar, protic solvent is preferably added during the acidification described above.
In contrast to prior procedures, the product of the reductive alkylation process is not isolated but the reaction mixture is contacted with an amine to remove the protecting group (i.e., R 3 ) from the intermediate product. Any suitable amine may be used in this step of the process. Representative amines suitable for use include, by way of example, methylamine, ethylamine, tert-butylamine, triethylamine, piperidine, morpholine, ammonium hydroxide, 1,4-diazabicyclo[2.2.2]octane (DABCO) and the like. Preferred amines are methylamine, tert-butylamine, ammonium hydroxide and 1,4-diazabicyclo[2.2.2]octane.
This deprotection step is typically conducted at a temperature ranging from about 0° C. to about 60° C., preferably at about 40° C. to about 45° C., for about 2 to about 60 hours, preferably for about 3 to about 10 hours, or until the reaction is substantially complete. This step is typically conducted in an inert diluent, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, and the like. The resulting compound of formula IV is readily isolated and purified by conventional procedures, such as precipitation, filtration and the like.
In the next step of the process, the compound of formula IV is contacted with formaldehyde and a compound of formula V:
wherein R 4 is as defined herein; in the presence of a base to provide a compound of formula I, or a salt thereof.
This step of the process is typically conducted by contacting one equivalent of compound IV or a salt thereof with one or more equivalents, preferably with about 2 to about 10 equivalents of a compound of formula V, and with an excess, preferably with about 4 to about 5 equivalents, formaldehyde in the presence of a base.
Phosphonate compounds of formula V are either commercially available or can be prepared by conventional procedures using commercially available starting materials and reagents. See for example, Advanced Organic Chemistry , Jerry March, 4th ed, 1992, John Wiley and Sons, New York, page 959; and Frank R. Hartley (ed.) The Chemistry of Organophosphorous Compounds , vol. 1-4, John Wiley and Sons, New York (1996). Aminomethylphosphonic acid is commercially available from Aldrich Chemical Company, Milwaukee, Wis.
The formaldehyde employed in this step of the process is typically added in an aqueous solution, for example, as a 37 wt. % solution in water optionally containing about 5 to about 15 wt. % methanol (i.e., Formalin).
Any suitable base may be used in this reaction including, for example, organic bases such as tertiary amines, and inorganic bases, such as alkali metal hydroxides (i.e., sodium hydroxide). Preferably, the base is a tertiary amine including, by way of example, triethylamine, diisopropylethylamine, and the like. A preferred tertiary amine is diisopropylethylamine. Preferably, the molar ratio of tertiary amine to compound V is about 3:1 to about 5:1; more preferably, about 3.5:1 to about 4.5:1; and still more preferably, about 4:1. Preferably, the pH of the reaction mixture is preferably about 10 to about 11.
Preferably, this reaction is conducted in an inert diluent, such as water, acetonitrile/water and the like. In a preferred embodiment, this step of the process is conducted in acetonitrile/water or water having v/v ratio ranging from about 3:2 to completely water.
This step of the process is typically conducted at a temperature ranging from about −20° C. to about 20° C., preferably at about −10° C. to about −5° C., for about 6 to about 48 hours, or until the reaction is substantially complete.
The resulting compound of formula I or a salt thereof is isolated by conventional procedures including, precipitation, filtration and the like. In a preferred isolation procedure, the pH of the reaction mixture is adjusted to about 2 to about 3 by addition of a suitable acid, such as aqueous hydrochloride acid. Preferably, the temperature of the reaction mixture is maintained below about 5° C. during acidification. Acetonitrile is then added to promote precipitation of the reaction product (i.e., a compound of formula I) and the resulting precipitate is collected by filtration and optionally washed with additional acetonitrile.
If desired, the reaction product can be further purified using reverse-phase HPLC or other chromatographic methods. In a preferred embodiment, the product is purified using a resin as described in co-pending U.S. application Ser. No. 10/226,676, filed on Aug. 23, 2002; which application claims the benefit of U.S. Provisional Application No. 60/314,712, filed on Aug. 24, 2001; the disclosures of which are incorporated herein by reference in their entirety.
Among other advantages, the process of the present invention provides for improved yield, purity and selectivity, i.e., reductive alkylation at the vancosamine amino group is favored over reductive alkylation at the N-terminus (e.g., the leucinyl group) by at least 10:1, more preferably 20:1. Additionally, because the reductive alkylation and deprotection steps are conducted in a single reaction vessel without isolation of the reaction intermediates, the process of the present invention is more efficient, provides a higher yield and generates less waste then previous processes.
The glycopeptide derivatives produced by the process of this invention are useful as antibiotics. See, for example, U.S. patent application Ser. No. 09/847,042, filed May 1, 2001; the disclosure of which is incorporated herein by reference in its entirety.
Additional details of the process of this invention are described in the following Examples which are offered to illustrate this invention and are not to be construed in any way as limiting the scope of this invention.
EXAMPLES
In the examples below, the following abbreviations have the following meanings. Any abbreviations not defined have their generally accepted meaning. Unless otherwise stated, all temperatures are in degrees Celsius (° C.).
DIPEA=diisopropylethylamine
DMF=N,N-dimethylformamide
DMSO=dimethyl sulfoxide
eq.=equivalent
Fmoc=9-fluorenylmethoxycarbonyl
TFA=trifluoroacetic acid
In the following examples, vancomycin hydrochloride semi-hydrate was purchased from Alpharma, Inc. Fort Lee, N.J. 07024 (Alpharma AS, Oslo Norway). Other reagents and reactants are available from Aldrich Chemical Co., Milwaukee, Wis. 53201.
Example A
Preparation of N-Fmoc-Decylaminoacetaldehyde
Step A
Preparation of N-Fmoc-2-(n-Decylamino)ethanol
2-n-Decylamino)ethanol (2.3 g, 11 mmol, 1.1 eq) and DIPEA (2.0 mL, 11 mmol, 1.1 eq) were dissolved in methylene chloride (15 mL) and cooled in an ice bath. 9-Fluorenylmethyl chloroformate (2.6 g, 10 mmol, 1.0 eq) in methylene chloride (15 ml) was added, the mixture stirred for 30 minutes then washed with 3 N hydrochloric acid (50 mL) twice and saturated sodium bicarbonate (50 mL). The organics were dried over magnesium sulfate, and the solvents removed under reduced pressure. N-Fmoc-2-(n-decylamino)ethanol (4.6 g, 11 mmol, 108%) was used without further purification.
Step B
Preparation of N-Fmoc-2-(n-Decylamino)acetaldehyde
To a solution of oxalyl chloride (12.24 mL) and methylene chloride (50 mL) at −35 to −45° C. was added DMSO (14.75 g) in methylene chloride (25 mL) over 20 minutes. The reaction mixture was stirred for 10 minutes at −35 to −45° C. A solution of N-Fmoc-2-(n-decylamino)ethanol (20.0 g) in methylene chloride (70 mL) was added over 25 minutes and then stirred 40 minutes at −35 to −45° C. Triethylamine (21.49 g) was then added and the mixture stirred for 30 minutes at −10 to −20° C. The reaction mixture was quenched with water (120 mL) followed by concentrated sulfuric acid (20.0 g) while maintaining the internal temperature at 0-5° C. The organic layer was isolated and washed with 2% sulfuric acid (100 mL) followed by water (2×100 mL). The organic solution was distilled under vacuum at 60° C. to about 100 mL. Heptane (100 mL) was added, the temperature of the oil bath raised to 80° C. and the distillation was continued until the residual volume was 100 mL. More heptane (100 mL) was added and the distillation repeated to a volume of 100 mL. The heating bath was replaced with a cold water bath at 15° C. The bath was cooled slowly to 5° C. over 20 minutes to start the precipitation of the product. The slurry was then cooled to −5 to −10° C. and the slurry was stirred for 2 hours. The solid was then collected on a Buchner funnel and washed with cold (−5° C.) heptane (2×15 mL). The wet solid was dried in vacuo to yield the title aldehyde.
Example 1
Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride
To a stirred mixture of 20 g (13.46 mmol) of vancomycin hydrochloride and 6.526 g (15.48 mmol) of N-Fmoc-2-(n-decylamino)acetyldehyde was added 130 mL of N,N-dimethylformamide and 4.7 mL (26.92 mmol) of N,N-diisopropylethylamine. The resulting mixture was stirred at room temperature under nitrogen for 15 hours, and 75 mL of methanol and 4.15 mL of trifluoroacetic acid (53.84 mmol) were added at 0° C. successively. The mixture was stirred for 1 hour and 1.93 mL (15.48 mmol) of borane-pyridine complex was added. The resulting mixture was stirred for 4 hours at 0° C., and 80 mL (161.52 mmol) of a2 M methylamine in methanol was added. The resulting mixture was warmed to room temperature and stirred for 50 hours, cooled to 0° C., and water (350 mL) was added dropwise. The mixture was acidified to pH 3.60 by slow addition of 11 mL of concentrated hydrochloric acid, and precipitation occurred. The mixture was stirred for another 30 min and then it was filtered through a Buchner funnel. The resulting wet cake was washed with water (2×200 mL) and dried in vacuo for 16 hours to give 9.8 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride. This intermediate may then be used in step (c) of the process as described in Example 3.
Example 2
Preparation of N van -2-(n-Decylamino)ethyl Vancomycin Hydrochloride
To a 1L three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen bubbler was added 180 mL of N,N-dimethylformamide (DMF). While stirring, 6.75 g (0.0160 mol) of N-Fmoc-2-(n-decylamino)-acetyldehyde and 25 g (0.0168 mol) of vancomycin hydrochloride were added successively. The addition funnel was rinsed with 20 mL of DMF; and then 5.85 mL (0.0336 mol) of N,N-diisopropylethylamine were added. The resulting mixture was stirred at room temperature under nitrogen for 6-8 hours while maintaining the temperature at 20-25° C. Methanol (95 mL) was added in one portion and then 5.2 mL (0.0672) of trifluoroacetic acid were added within 1 minute. The mixture was stirred for 0.25 hours and then 1.39 g (0.016 mol) of borane-tert-butyl amine complex were added to the reaction mixture in one portion. The addition funnel was rinsed with 5 mL of methanol, and the resulting mixture was stirred for 2 hours at room temperature. tert-Butylamine (10.6 mL, 0.101 mol) was added in one portion and the resulting mixture was stirred at 40-42° C. for about 7 hours. The reaction mixture was then cooled to room temperature and 140 mL of 0.5 N HCl were added, followed by 600 mL of a 10% brine solution at room temperature. The resulting mixture was stirred for 2 hours at 20-25° C., and then cooled to 10° C. and stirred for 1 hour. The resulting precipitate is collected using a 12.5 cm Buchner funnel by filtering the reaction mixture over a period of about 90 min. The wet cake was washed with cold water (2×50 mL) and sucked dry for 5 hours. The resulting material was added to 200 mL of acetonitrile while stirring to 2 hours at 20-25° C. The resulting slurry was filtered through an 8 cm Buchner funnel and the collected wet cake was washed with acetonitrile (2×25 mL) and dried under house vacuum (about 25 mm Hg) for 13 hours to afford 31.1 g of crude N van -2-(n-decylamino)ethyl vancomycin hydrochloride. This intermediate may then be used in step (c) of the process as described in Example 3.
Example 3
Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin
A 250 mL of three-necked round bottom flask equipped with a mechanical stirrer, a thermometer and a nitrogen outlet was charged with 5 g of N van -2-(n-decylamino)ethyl vancomycin and 1.6 g of aminomethylphosphonic acid and 30 mL of acetonitrile. The slurry was stirred for 15 minutes to allow disperse solids at 20-30° C. and then 20 mL of water was added. The mixture was agitated for 15 minutes and 7.5 g of diisopropylethylamine was added. The resulting mixture was agitated until all solids dissolved. The reaction mixture was then cooled to −5 to −10° C. and 2.5 g of 3.7% aqueous formaldehyde was charged and the resulting mixture was agitated at −5 to −10° C. for 24 hours. The reaction was monitored by HPLC. After the reaction was complete, the reaction mixture was adjusted to pH 2-3 with 3M hydrochloric acid solution while maintaining the reaction temperature at −10 to 5° C. With moderate agitation, 125 mL of acetonitrile was added to the reaction mixture at 20 to 25° C. over 10 minutes. The resulting mixture was stirred at 20 to 25° C. for 2 hours and then filtered. The wet cake was washed with 20 mL of acetonitrile twice and dried for 18 hours in a vacuum oven at 20 to 25° C. to give 5.3 g of the title compound as a mixture of the di- and trihydrochloride salt in ˜100% yield with a purity of ca. 80% (HPLC area) (i.e., a compound of formula I where R 1 is —CH 2 CH 2 —, R 2 is n-decyl and R 4 is —CH 2 —).
Example 4
Preparation of N van -2-(n-Decylamino)ethyl 29-{[(Phosphonomethyl)amino]methyl}Vancomycin
To a 12-L jacketed three-necked flask equipped with a mechanical stirrer, nitrogen inlet and temperature probe was added 117 g (ca. 60 mmol) of N van -2-(n-decylamino)ethyl vancomycin (ca. 80% a purity). Aminomethylphosphonic acid (30 g, 320 mmol) was then added, followed by 420 mL of acetonitrile. The resulting slurry was stirred for 15 minutes and then 426 g of water was added and stirring continued for 15 minutes. Diisopropylethylamine (144 g, 1500 mmol) was added ant the mixture was stirred at room temperature for 1 hour. The resulting light pink solution was cooled to −7° C. (internal temperature) and 4.51 g (60 mmol) of 37% aqueous formaldehyde in 33 mL of acetonitrile were added. The resulting mixture was stirred at −7° C. (internal temperature) for 12 hours while monitoring the reaction by HPLC. After the reaction was complete (i.e., <1% starting material after 12 hours), the pH of the reaction mixture was adjusted from 10.4 to 2.59 by addition of 3 N aqueous hydrochloric acid solution while maintaining the internal reaction temperature at −4 to −5° C. The amount of 3 N aqueous hydrochloride acid used was 455 g. To the resulting mixture was added 3.1 kg of 95% ethanol at 5° C. and the mixture was stirred for 3 hours, and then filtered through a Buchner funnel. The resulting wet cake was washed with 500 g of ethyl acetate to give 135 g of a granular solid. This solid was dried at 30 mmHg at room temperature for 20 hours to give 116 g of the title compound as a mixture of the di- and trihydrochloride salt. Karl Fisher assay of this material showed an 11% water content; and HPLC analysis showed 1.7% unreacted glycopeptide and 3.6% bis-Mannich byproduct relative to the title compound.
While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. Additionally, all publications, patents, and patent documents cited hereinabove are incorporated by reference herein in full, as though individually incorporated by reference. | Disclosed are processes for preparing glycopeptide phosphonate derivatives having an amino-containing side chain. Several of the process steps are conducted in a single reaction vessel without isolation of intermediate reaction products, thereby generating less waste and improving the overall efficiency and yield of the process. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is related to a cushion insert for a strap. More particularly, the present invention is related to straps for a device or garment, such as a brassiere, having a cushion insert.
[0003] 2. Description of Related Art
[0004] Many items require a strap that traverses one or more shoulders of a user to aid in supporting the weight of a carried object. For example, a backpack, a piece of luggage, a briefcase, a purse, a sport equipment bag, and other items can include a strap that traverses a user's shoulder(s)
[0005] Additionally, garments such as a medical sling, a brassiere, a woman's bathing suit, a leotard, and other garments, can aid in supporting a portion of a wearer's body. In these applications, the garment can include one or more straps positioned to traverse the wearer's shoulder(s) and, thus, transfer a portion of the supported load to the shoulders.
[0006] In order to improve the comfort to the wearer, some straps have included padding, cushioning, and/or load spreading surfaces incorporated into the strap.
[0007] However, there is a continuing desire for new and better cushion straps to further increase the comfort of a wearer.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a cushion insert for a strap.
[0009] It is another object to provide a strap that is cushioned with a gel material.
[0010] It is yet another object to provide a gel cushioned strap that restrains movement of the gel material away from the body of the wearer.
[0011] These and other objects and advantages of the present invention are provided by a cushion insert having a cushion material, a support member, and a cover. The cushion material is enclosed by an upper ply and a lower ply. The support member is disposed on the upper ply. The cover secures the support member to the upper ply so that the support member restrains expansion of the cushion material toward the upper ply.
[0012] These and other objects and advantages of the present invention are also provided by a cushioned strap having a first layer facing a first direction and a second layer facing a second, opposite direction. The cushioned strap has a gelatinous cushion enclosed between a first ply and a second ply. The gelatinous cushion is positioned between the first and second layers so that the second ply is adjacent the second layer. The support member is secured on the first ply by a cover, which is adjacent the first layer. The support member restrains movement of the gelatinous cushion in the first direction upon application of a force to the cushioned strap from the second direction.
[0013] Further, the objects and advantages of the present invention are provided by a brassiere having a body-encircling portion having, a strap, and a cushion insert. The body-encircling portion has a pair of breast cups for receiving the breasts of a wearer. The strap secures the body-encircling portion across an interface region of the wearer. The cushion insert is disposed at the interface region. The cushion insert has a gel material proximate the interface region and a support member covering the gel material remote from the interface region. Thus, a force applied to the cushion insert by the interface region is restrained from expanding the gel material away from the interface region.
[0014] The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] [0015]FIG. 1 is a perspective view of an exemplary embodiment of a garment having a cushion strap according to the present invention;
[0016] [0016]FIG. 2 is top view of the cushion strap of FIG. 1;
[0017] [0017]FIG. 3 is a sectional view of the cushion strap taken along lines 3 - 3 of FIG. 2; and
[0018] [0018]FIG. 4 is an exploded view of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring to the drawings and in particular to FIG. 1, a supporting device 10 is illustrated by way of example as a garment, particularly a brassiere. Device 10 includes one or more straps 12 positioned to traverse the shoulder of a wearer at an interface region 14 .
[0020] In the illustrated embodiment where device 10 is a brassiere, the brassiere includes breast cups 16 defined in a body-encircling portion 18 . In use, portion 18 is positioned around the body so that the breasts of the wearer are received in and supported by breast cups 16 . In this position, straps 12 transfer a portion of the load supported by device 10 from portion 18 and, thus, cups 16 to interface region 14 .
[0021] It should be recognized that device 10 is illustrated by way of example as a brassiere having two straps 12 such that interface region 14 is the shoulders of the wearer. Of course, it is contemplated by the present invention for the brassiere to have a single strap 12 that traverse the back of the neck of the wearer (i.e., interface region 14 is the neck of the wearer). Moreover, it is contemplated for interface region 14 to be any support surface such as a shoulder, arm, neck, or other region of the body of the wearer.
[0022] In order to cushion the effect of straps 12 on interface region 14 , device 10 includes a cushion insert 20 according to the present invention at the interface region.
[0023] Cushion insert 20 is described with simultaneous reference to FIGS. 2-4. Insert 20 is a multi-layer structure configured to provide cushioning for region 14 , as well as to spread the load of device 10 across a larger area than possible with strap 12 alone.
[0024] Insert 20 is, preferably, disposed in strap 12 . Specifically, strap 12 has a first layer 22 and a second facing layer 24 . First and second layers 22 , 24 are, preferably, fabric layers. For example, layers 22 , 24 can be formed of fabric made of natural fibers (e.g., cotton), synthetic fibers (e.g., nylon), and any combination thereof.
[0025] First layer 22 faces the body of the wearer, while second layer 24 faces away from the body of the wearer. Insert 20 is, preferably, disposed between first and second layers 22 , 24 , respectively.
[0026] Of course, it is contemplated by the present invention for insert 20 to be secured to first layer 22 or second layer 24 of the strap. Alternately, it is contemplated for strap 12 to have only one layer and for insert 20 to be secured to either side of the single layer strap.
[0027] Insert 20 includes a cushion material 26 , which is, preferably, a gelatinous material. As used herein, “gelatinous” shall mean a semi-solid material having flowable or viscous properties. For example, cushion material 26 can be a silicone gel commercially available from Grupo Empressarial of Columbia and having a brookfield viscosity of about 4100 centipoise (cps) at 25 degrees Celsius. Of course, it is contemplated by the present invention for cushion material 26 to be other gelatinous materials having a higher or lower viscosity.
[0028] Cushion material 26 is contained between a lower ply 28 and an upper ply 30 of plastic material. For example, upper and lower plies 28 , 30 can be polyvinyl chloride (e.g., PVC).
[0029] In use, region 14 applies a force on insert 20 in the direction of arrow 32 . It has been found that force 32 causes cushion material 26 to move away from region 14 , which can limit the cushioning effects of the cushion material. For example, it has been found that force 32 causes cushion material 26 to exert pressure on upper ply 30 in a direction away from the force, which can cause the upper ply to expand outward away from region 14 .
[0030] Advantageously, insert 20 includes a support member 34 positioned at upper ply 30 . In this position, support member 34 can mitigate the occurrence of cushion material 26 expanding outward away from region 14 . Namely, support member 34 can aid in applying a restraining force to cushion material 26 in a direction opposite force 32 . Thus, support member 34 has been found to be effective at maintaining the cushioning effects of cushion material 36 to a greater degree than is possible without the support member.
[0031] Support member 34 can be formed of a rubber material, such as ethylene vinyl acetate (EVA) rubber. Preferably, support member 34 is an open or closed celled foam EVA rubber material. In addition, support member 34 is, preferably, secured to upper ply 30 with a cover 36 . Cover 36 can be the same material as upper and lower plies 28 , 30 . Alternately, cover 36 can be a different material than upper and lower plies 28 , 30 .
[0032] Accordingly, insert 20 is a multi-layer structure including cover 36 , support member 34 , upper ply 30 , cushion material 26 , and lower ply 28 . Cushion material 26 , preferably, has viscous properties to distribute and cushion force 32 across region 14 . In addition, support member 34 aids in mitigating the flow of cushion material 26 outwards away from region 14 , which has been found to increase the cushioning effect of the cushion material.
[0033] Thus, insert 20 is particularly suited for insertion into and/or securement to strap 12 to easily and quickly render the strap a cushioned strap.
[0034] It should also be noted that the terms “first”, “second”, “third”, “upper”, “lower”, and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated.
[0035] While the present invention has been described with reference to one or more exemplary embodiments, 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 present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present invention not be limited to the particular embodiment(s) 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 cushion insert having a cushion material, a support member, and a cover is provided. The cushion material is enclosed by an upper ply and a lower ply. The support member is disposed on the upper ply. The cover secures the support member to the upper ply so that the support member restrains expansion of the cushion material toward the upper ply. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lampholder.
2. Description of the Related Art
As shown in FIG. 9, a conventional lampholder includes a body 47 , a female screw shell 48 , a central contact spring 49 , a cover 50 , power terminal boards 52 a, 52 b, and lead wires 53 a, 53 b. The body 47 is made of insulating resin or ceramic and is in the form of a cylinder with the bottom. The female screw shell 48 is made of metal and connected electrically to a shell (not shown), e.g., of an E-type cap (not shown) for a lamp (not shown). Similarly, the central contact spring 49 is made of metal and connected electrically to an eyelet (not shown) of the cap. The cover 50 is made of insulating resin or ceramic and provided at the end of the body 47 . The power terminal boards 52 a, 52 b are fastened on the inner surface of the cover 50 with a pair of screws 51 (one of them is not shown). The lead wires 53 a, 53 b are connected electrically to the power terminal boards 52 a, 52 b.
The body 47 and the cover 50 are connected mechanically with two screws 54 a, 54 b. One screw 54 a mechanically connects the body 47 and the female screw shell 48 , and also electrically connects the female screw shell 48 and the power terminal board 52 a. The other screw 54 b mechanically connects the body 47 and the central contact spring 49 , and also electrically connects the central contact spring 49 and the power terminal board 52 b.
A screw 55 is used to adjust the amount of movement of the central contact spring 49 when the cap is inserted. The screw 55 prevents the contact failure between the central contact spring 49 and the eyelet resulting from unnecessary movement of the central contact spring 49 toward the cover 50 .
However, in the conventional lampholder, many screws or the like are necessary to fasten each part together, particularly, to fasten the component of resin or ceramic, such as the body 47 , and that of metal, such as the female screw shell 48 . This requires the steps of tightening those screws as well. In other words, the parts are increased and the process is complicated, which in turn increases the cost and reduces the productivity.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is an object of the present invention to provide a lampholder that can achieve the reduction of cost and the improvement of productivity by reducing the parts and simplifying the process.
A lampholder of the present invention for receiving a lamp cap includes a body, a receiving portion provided in the body and to be connected to the cap, and a lead wire connected to the receiving portion. The receiving portion is made of conductive resin.
Unlike a conventional lampholder, this configuration eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts can be reduced and the steps of tightening the screws or the like can be omitted. Thus, the reduction of cost as well as the improvement of productivity can be achieved.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional front view showing a lampholder of Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional front view showing a lampholder of Embodiment 2 of the present invention.
FIG. 3 is a cross-sectional front view showing a lampholder of Embodiment 3 of the present invention.
FIG. 4 is a cross-sectional front view showing a lampholder of Embodiment 4 of the present invention.
FIG. 5 is a cross-sectional front view showing a lampholder of Embodiment 5 of the present invention.
FIG. 6 is a cross-sectional front view showing a lampholder of Embodiment 6 of the present invention.
FIG. 7 is a cross-sectional front view showing a lampholder of Embodiment 7 of the present invention.
FIG. 8 is a cross-sectional front view showing a lampholder of Embodiment 8 of the present invention.
FIG. 9 is a cross-sectional front view showing a conventional lamp holder.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
Embodiment 1
As shown in FIG. 1, an E-type cap 2 (e.g., E26-type), e.g., for a bulb-shaped fluorescent lamp 1 is inserted in a lampholder of Embodiment 1 of the present invention.
The lampholder includes a body 3 , a receiving portion 4 , and a cover 5 . The body 3 is made of insulating resin and is in the form of a cylinder having a length of 35 mm, outer diameter of 35 mm, and inner diameter of 30 mm. The receiving portion 4 is made of conductive resin, provided on the inner surface of the body 3 , and to be connected electrically to the cap 2 . The cover 5 has a height of 15 mm and outer diameter of 35 mm, and is provided at the end of the body 3 .
The body 3 and the receiving portion 4 are formed as an integral component.
The body 3 is connected to the cover 5 by engaging a convexity 3 a at the end of the body 3 with a concavity 5 a at the end of the cover 5 .
Examples of the conductive resin used for the receiving portion 4 include a material prepared by mixing polybutylene terephthalate resin or polyphenylene sulfide resin with a conductive material, such as carbon black, metallic fiber, carbon fiber, metallic flakes, metallized glass beads, metallized glass fiber, and organic polymer.
The receiving portion 4 is provided with a first terminal 6 and a second terminal 7 . The first terminal 6 has an internal thread 6 a on the inner surface, into which a shell 2 a of the cap 2 , having an external thread, is screwed to establish the electrical connection between them. The second terminal 7 has a protruding contact portion 7 a (with a protrusion length of 1 mm to 3 mm) that is connected electrically to an eyelet 2 b at the end of the cap 2 . The ends of the lead wires 8 a, 8 b, having a cross-sectional area of 0.75 mm 2 to 1.25 mm 2 , are embedded directly in the first and the second terminals 6 , 7 , respectively, to establish the electrical connection. The length of the embedded portion of each lead wire 8 a, 8 b is 5 mm or more. The other ends of the lead wires 8 a, 8 b are drawn from a hole 5 b in the center of the cover 5 to the outside of the lampholder. An insulating member 9 is provided between the first terminal 6 and the second terminal 7 to insulate the two terminals from one another.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 1 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts can be reduced significantly and the steps of tightening the screws or the like also can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved.
In particular, since the body 3 of insulating resin and the receiving portion 4 of conductive resin are formed as an integral component, the assembly of the body 3 and the receiving portion 4 can be omitted, thus increasing the productivity further.
Embodiment 2
Next, a lampholder of Embodiment 2 of the present invention has the same configuration as that of a lampholder of Embodiment 1 of the present invention except that the structure of a receiving portion 10 and a means for connecting lead wires 8 a, 8 b and the receiving portion 10 are different, as shown in FIG. 2 .
The receiving portion 10 is provided with a first terminal 11 and a second terminal 12 . The first terminal 11 is made of conductive resin and has an internal thread 11 a on the inner surface, into which a shell (not shown) of a cap (not shown), having an external thread, is screwed to establish the electrical connection between them. The second terminal 12 is made of conductive resin and has a protruding contact portion 12 a (with a protrusion length of 1 mm to 3 mm) that is connected electrically to an eyelet (not shown) at the end of the cap. A body 3 and the receiving portion 10 are formed as an integral component.
An insulating member 9 is provided between the first terminal 11 and the second terminal 12 to insulate the two terminals from one another. Each of the first and the second terminals 11 , 12 has a through hole 14 for screws so that a fastener 13 composed, e.g., of a tapping screw is driven into the hole.
The lead wire 8 a is connected electrically to the first terminal 11 by fastening a pressure connector 15 with the fastener 13 , the pressure connector 15 being connected to the end of the lead wire 8 a.
Similarly, the lead wire 8 b is connected electrically to the second terminal 12 by fastening a pressure connector 15 with the fastener 13 , the pressure connector 15 being connected to the end of the lead wire 8 b.
In FIG. 2, reference numeral 16 indicates a washer.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 2 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, the lead wires 8 a, 8 b can be removed from the lampholder easily, which facilitates the replacement of damaged parts caused, e.g., by disconnection of the lead wires 8 a, 8 b.
Embodiment 3
Next, a lampholder of Embodiment 3 of the present invention has the same configuration as that of a lampholder of Embodiment 2 of the present invention except that screws (fasteners 17 a in FIG. 3) and nuts (fasteners 17 b in FIG. 3) are used instead of tapping screws to connect a receiving portion 10 and lead wires 8 a, 8 b electrically, as shown in FIG. 3 .
In FIG. 3, reference numeral 18 indicates a hole for screws.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 3 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together, just as in the lampholder of Embodiment 2 of the present invention. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, the lead wires 8 a, 8 b can be removed from the lampholder easily, which facilitates the replacement of damaged parts caused, e.g., by disconnection of the lead wires 8 a, 8 b.
Embodiment 4
Next, a lampholder of Embodiment 4 of the present invention includes a body 19 , a receiving portion 20 , and a cover 21 , as shown in FIG. 4 . The body 19 is made of insulating resin and is in the form of a cylinder having a length of 35 mm, outer diameter of 35 mm, and inner diameter of 30 mm. The receiving portion 20 is made of conductive resin, provided on the inner surface of the body 19 , and to be connected electrically to a cap (not shown). The cover 21 has a height of 15 mm and outer diameter of 35 mm, and is provided at the end of the body 19 .
The body 19 and the receiving portion 20 are formed as an integral component.
The receiving portion 20 is provided with a first terminal 22 and a second terminal 23 . The first terminal 22 has an internal thread 22 a on the inner surface, into which a shell (not shown) of the cap, having an external thread, is screwed to establish the electrical connection between them. The second terminal 23 has a protruding contact portion 23 a (with a protrusion length of 1 mm to 3 mm) that is connected electrically to an eyelet (not shown) at the end of the cap. Each of the first and the second terminals 22 , 23 has a through hole 25 for screws so that a fastener 24 composed, e.g., of a screw is inserted into the hole. An insulating member 9 is provided between the first terminal 22 and the second terminal 23 to insulate the two terminals from one another.
The cover 21 has power terminal boards 27 a, 27 b on the inner surface, the power terminal boards 27 a, 27 b being connected electrically to the ends of the lead wires 8 a, 8 b by a pair of screws 26 (one of them is not shown). The other ends of the lead wires 8 a, 8 b are drawn from a hole 21 a in the center of the cover 21 to the outside of the lampholder.
The first terminal 22 and the power terminal board 27 a are connected electrically via the fastener 24 . Similarly, the second terminal 23 and the power terminal board 27 b are connected electrically via the fastener 24 . Those fasteners 24 connect the body 19 and the cover 21 mechanically as well.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 4 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. In addition, the mechanical connection between the body 19 and the cover 21 and the electrical connection between the receiving portion 20 and the lead wires 8 a, 8 b can be made at the same time. Thus, the cost can be reduced and the productivity also can be increased further.
Embodiment 5
Next, a lampholder of Embodiment 5 of the present invention has the same configuration as that of a lampholder of Embodiment 1 of the present invention except that a receiving portion 4 and lead wires 8 a, 8 b are connected electrically via metallic terminals 28 , 29 that are made of copper or brass and embedded in the receiving portion 4 , as shown in FIG. 5 .
The metallic terminal 28 is in the form of a plate having a length of 27 mm, width of 5 mm to 7 mm, and thickness of 0.1 mm to 1.0 mm. The length of the embedded portion of the metallic terminal 28 in a first terminal 6 is 20 mm. On the other hand, the metallic terminal 29 is in the form of a plate having a length of 20 mm, width of 5 mm to 7 mm, and thickness of 0.1 mm to 1.0 mm and is bent to have an L shape. The length of the embedded portion of the metallic terminal 29 in a second terminal 7 is 13 mm.
The lead wires 8 a, 8 b are connected electrically to the metallic terminals 28 , 29 , respectively, by caulking.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 5 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, since the receiving portion 4 and the lead wires 8 a, 8 b are connected electrically via the metallic terminals 28 , 29 , the operation of connecting the receiving portion 4 and the lead wires 8 a, 8 b can be performed easily.
In particular, the metallic terminal 29 is bent to have an L shape, thereby preventing it from slipping off the receiving portion 4 (the second terminal 7 ).
Example 6
Next, a lampholder of Embodiment 6 of the present invention includes a body 30 , a first terminal 31 , a central contact spring 32 , and a cover 5 , as shown in FIG. 6 . The body 30 is made of insulating resin and is in the form of a cylinder with the bottom, having a total length of 35 mm, outer diameter of 35 mm, and inner diameter of 30 mm. The first terminal 31 is made of conductive resin and provided on the inner surface of the body 30 . Also, the first terminal 31 has an internal thread 31 a on the inner surface, into which a shell (not shown) of a cap (not shown), having an external thread, is screwed to establish the electrical connection between them. The central contact spring 32 is made of copper or brass, has an L shape, length of 32 mm, width of 5 mm to 7 mm, and thickness of 0.2 mm to 1.0 mm, and is connected electrically to an eyelet (not shown) at the end of the cap. The cover 5 has a height of 15 mm and outer diameter of 35 mm, and is provided on a bottom 30 a of the body 30 .
The body 30 and the first terminal 31 are formed as an integral component.
The cover 5 is connected to the body 30 by engaging a concavity 5 a at the end of the cover 5 with a convexity 30 b at the bottom 30 a of the body 30 .
A metallic terminal 28 in the form of a plate having a length of 27 mm, width of 5 mm to 7 mm, and thickness of 0.1 mm to 1.0 mm is embedded in the first terminal 31 to establish the electrical connection between them. The length of the embedded portion of the metallic terminal 28 is 20 mm. Also, the metallic terminal 28 is connected electrically to a lead wire 8 a by caulking, the lead wire 8 a being drawn from a hole 5 b in the center of the cover 5 to the outside of the lampholder. In other words, the lead wire 8 a and the first terminal 31 are connected electrically via the metallic terminal 28 .
The bottom 30 a of the body 30 holds the central contact spring 32 , which penetrates the bottom 30 a. One end of the central contact spring 32 is connected electrically to a lead wire 8 b by caulking. When a cap is inserted in the lampholder, the other end of the central contact spring 32 is pushed toward the cover 5 into contact with a projection 30 c at the center of the bottom 30 a of the body 30 and is connected electrically to the eyelet of the cap. In this case, force acts to move the other end of the central contact spring 32 back to the cap side, so that the electrical connection between the central contact spring 32 and the eyelet can be established reliably.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 6 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, the central contact spring 32 of metal is used to make the electrical connection with the eyelet, thereby decreasing contact failure and increasing reliability.
Embodiment 7
Next, a lampholder of Embodiment 7 of the present invention includes a body 33 , a first terminal 34 , a central contact spring 35 , and a cover 5 , as shown in FIG. 7 . The body 33 is made of insulating resin and is in the form of a cylinder with the bottom, having a total length of 35 mm, outer diameter of 35 mm, and inner diameter of 30 mm. The first terminal 34 is made of conductive resin and provided on the inner surface of the body 33 . Also, the first terminal 34 has an internal thread 34 a on the inner surface, into which a shell (not shown) of a cap (not shown), having an external thread, is screwed to establish the electrical connection between them. The central contact spring 35 is made of copper or brass, has an L shape, length of 25 mm, width of 5 mm to 7 mm, thickness of 0.2 mm to 1.0 mm, and is connected electrically to an eyelet (not shown) at the end of the cap. The cover 5 has a height of 15 mm and outer diameter of 35 mm, and is provided on the side of a bottom 33 a of the body 33 .
The body 33 and the first terminal 34 are formed as an integral component.
The cover 5 is connected to the body 33 by engaging a concavity 5 a at the end of the cover 5 with a convexity 33 b at the bottom 33 a of the body 33 .
A metallic terminal 36 in the form of a plate having a length of 25 mm, width of 5 mm to 7 mm, and thickness of 0.1 mm to 1.0 mm is embedded in the first terminal 34 to establish the electrical connection between them. The length of the embedded portion of the metallic terminal 36 is 18 mm. A pressure connector 37 a, connected to a lead wire 8 a, is fastened and electrically connected to the metallic terminal 36 with a fastener 38 a composed of a screw.
The bottom 33 a of the body 33 holds the central contact spring 35 , which penetrates the bottom 33 a. A pressure connector 37 b, connected to a lead wire 8 b, is fastened and electrically connected to the central contact spring 35 with a fastener 38 b composed of a screw.
In FIG. 7, reference numeral 39 indicates a hole for screws.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 7 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, the central contact spring 35 of metal is used to make the electrical connection with an eyelet, thereby decreasing contact failure and increasing reliability. Moreover, the lead wires 8 a, 8 b can be removed from the lampholder easily, which facilitates the replacement of damaged parts caused, e.g., by disconnection of the lead wires 8 a, 8 b.
Embodiment 8
Next, a lampholder of Embodiment 8 of the present invention includes a body 30 , a first terminal 31 , a central contact spring 40 , and a cover 41 , as shown in FIG. 8 . The body 30 is made of insulating resin and is in the form of a cylinder with the bottom. The first terminal 31 is made of conductive resin and provided on the inner surface of the body 30 . Also, the first terminal 31 has an internal thread 31 a on the inner surface, into which a shell (not shown) of a cap (not shown), having an external thread, is screwed to establish the electrical connection between them. The central contact spring 40 is made of copper or brass, has an L shape, length of 30 mm, width of 5 mm to 7 mm, and thickness of 0.2 mm to 1.0 mm, and is connected electrically to an eyelet (not shown) at the end of the cap. The cover 41 has a height of 15 mm and outer diameter of 30 mm, and is provided on a bottom 30 a of the body 30 .
The body 30 and the first terminal 31 are formed as an integral component.
The body 30 is connected to the cover 41 by engaging a convexity 30 b at the bottom 30 a of the body 30 with a concavity 41 a at the end of the cover 41 .
A metallic terminal 42 in the form of a plate having a length of 27 mm, width of 5 mm to 7 mm, and thickness of 0.1 mm to 1.0 mm is embedded in the first terminal 31 to establish the electrical connection between them. The length of the embedded portion of the metallic terminal 42 is 20 mm.
The bottom 30 a of the body 30 holds the central contact spring 40 , which penetrates the bottom 30 a.
Two clip terminals 43 a, 43 b are embedded in the cover 41 on the inner surface thereof. One clip terminal 43 a clips the end of the metallic terminal 42 . Similarly, the other clip terminal 43 b clips the end of the central contact spring 40 .
Each of two lead wires 8 a, 8 b, drawn from a hole 41 b in the center of the cover 41 to the outside of the lampholder, has a pressure connector 44 at the end thereof. The pressure connectors 44 are connected electrically to the clip terminals 43 a, 43 b, respectively, e.g., by screws 45 or the like.
In FIG. 8, reference numeral 46 indicates a hole for screws.
Unlike a conventional lampholder, the above configuration of a lampholder of Embodiment 8 of the present invention eliminates the need to fasten the component of resin or ceramic, such as a body, and that of metal, such as a female screw shell, together. Therefore, many screws or the like are not necessary. As a result, the parts and the steps of tightening the screws or the like can be reduced, compared with the conventional lampholder. Thus, the reduction of cost as well as the improvement of productivity can be achieved. In addition, the central contact spring 40 of metal is used to make the electrical connection with the eyelet, thereby decreasing contact failure and increasing reliability. Moreover, the first terminal 31 and the central contact spring 40 can be connected electrically to the lead wires 8 a, 8 b easily.
As described in each of the embodiments, the receiving portions 4 , 10 , and 20 to be connected to a cap, including the first terminals 6 , 11 , 22 , 31 , and 34 and the second terminals 7 , 12 , and 23 , are made of conductive resin. Thus, compared with the conventional one made of metal, various means for connecting, e.g., the receiving portion to the lead wires 8 a, 8 b can be employed. This can facilitate handling and prevent corrosion, such as rust.
In the above embodiments, the lampholder for the E-type cap 2 of the bulb-shaped fluorescent lamp 1 is described. However, the present invention can be applied to the E-type cap or B-type cap of a general incandescent lamp, a high-pressure discharge lamp, or the like.
The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. | A lampholder for receiving a cap of a lamp includes a body, a receiving portion, and lead wires: the receiving portion is provided in the body and to be connected to the cap; the lead wires are connected to the receiving portion. The receiving portion is made of conductive resin. This configuration can reduce the parts, simplify assembly, lower the cost, and improve the productivity. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to a portable room air conditioner and is more specifically directed to the assembly of the condenser fan orifice to facilitate ease of construction, avoid the need for tools or small fasteners, and ensure that the orifice is located consistently and accurately to avoid fan hitting problems.
Portable window type air conditioners have a fan orifice disposed over the condenser fan on the outdoor side of the unit. The fan orifice is a generally flat member, having a round opening with a collar that surrounds the fan circumference. In a conventional unit, the condenser fan orifice is installed using gussets, arms, or other separate members, and these are Joined to the orifice and to the main frame of the unit using screws or clips. Invariably, tools are needed to install the condenser fan orifice.
Because of the large number of parts needed to install it, problems arise relating to the condenser fan orifice. Variations in shape, size, or placement of these parts create variations in location of the orifice over the associated fan.
This makes it difficult to assure consistent orifice location when the same is installed, and can result in fan hit problems. Correction of these problems on assembly adds manufacturing steps, and hence increases cost and reduces quality assurance factors. Also, the requirement for a number of parts translates into increased tooling costs, increased parts inventory and storage costs, and increased service part costs.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of this invention to provide a condenser fan orifice assembly for a room air conditioner which avoids the drawbacks of the prior art.
It is a more specific object to provide an air conditioner assembly in which the condenser fan orifice can be installed quickly and reliably, and without use of small fasteners or other additional parts.
It is a further object to provide a room air condition assembly with a condenser fan orifice which is accurately and securely located on installation to avoid fan hit problems.
According to an aspect of this invention, the orifice member is formed of an orifice plate with at least one lower support arm and one or more upper support posts formed integrally therewith. The orifice plate has the fan orifice formed in it so that it surrounds the circumference of the fan. There is an upwardly projecting tongue integrally formed on the partition plate below the fan motor which is mounted in the partition plate. This enters a transverse slot on the lower support arm. Then the orifice member is installed by rocking it into position, pivoting on the engagement of the tongue and slot.
The ends of the upper post or posts have engaging slots formed in them, and the partition plate has integrally formed tabs or fingers that projects towards the orifice plate, i.e., perpendicular to the partition plate. These tabs engage the corresponding slots in the posts when the orifice member is rocked into position. These slots have a wide portion into which the tabs enter. The tabs have cutouts or notches on their edges which engage a narrow portion of the slot and lock the orifice member in place.
The ends or tips of the posts have projecting stop members or standoffs that bias against the partition plate and also prevent the tab from moving out of the slot.
On the lower support arm tip, distally of the transverse slot, there is a rib that slants upward and outward. A nose or lance formed in the partition plate protrudes out behind the upwardly extending tongue. This lance engages the rib when the condenser fan orifice member is rocked into position, to hold the lower support arm securely.
It can be seen that in this system no screws, clips, nuts, or other fastener devices are used. The condenser fan orifice can be installed quickly and reliably without tools. Because the assembly here involves only the two pre-formed parts, namely the condenser fan orifice and partition, the orifice locates itself accurately and reliably, avoiding any fan hitting problems.
Also, because no screws, nuts or clips are used, there are no small parts to work loose in the air conditioner or to cause rattle or vibration noise.
The above and many other objects, features, and advantages of this invention will become apparent from the ensuing description of a preferred embodiment, which should be read in conjunction with the accompanying Drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a window air conditioner unit that embodies one example of the teachings of the present invention.
FIG. 2 is a side elevation of the air conditioner unit of FIG. 1, shown partly in ghost.
FIG. 3 is a top plan view of the air conditioner unit, shown partly in ghost.
FIG. 4 is a side assembly view of the partition plate and condenser fan orifice member according to a preferred embodiment of the invention.
FIGS. 5, 6, and 7 are enlarged detail views of portions of the preferred embodiment identified at 5--5, 6--6, and 7--7, respectively, of FIG. 4.
FIG. 8 is a detail view, partly cut away, of a portion of FIG. 3 identified at 8--8 thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the Drawing and initially to FIG. 1, a portable window air conditioning unit 10 has a front cover 11 that is positioned on an indoor side of the unit and a rear cover 12 on the exterior or outdoor side of the unit. The air conditioner unit 10 is intended to be positioned on a window sill, and expandable side curtains 13 open out to fill the window opening.
As shown in FIGS. 2 and 3 a sheet metal plate or diaphragm 14 serves as a partition and separates the indoor and outdoor portions of the air conditioner unit 10, with the outdoor side being illustrated at the left in FIG. 2 or at the top in FIG. 3.
An axial flow fan 15 has a fan motor 16 supported in the partition plate 14. The fan 15 impels cooling air outward through a condenser coil 17. The motor 16 also drives an indoor or evaporator fan, which is omitted here to avoid drawing clutter. The compressor, evaporator, receiver tube, and various connecting tubing have also been omitted here, but of course would be present in practice in the unit 10.
Also shown in FIGS. 2 and 3 is a condenser fan orifice member 18 which is positioned in a plane coincident with the condenser fan 15. The member 18 has a plate portion 19 with a circular fan orifice 20 therein formed of a collar 21 which surrounds the fan 15 circumferentially. The orifice member directs the air forced by the fan 15 through the condenser coil 17. The orifice member 18 has an integrally formed lower support arm 22 below the fan orifice 20 and a pair of integrally formed posts 23, 23 at the upper edge. These extend generally perpendicular to the orifice plate 19 and are secured onto the partition plate 14.
As shown in FIG. 4, the orifice member 18 is installed by placing the lower support arm 22 onto a mating element of the partition plate 14 and then rocking the orifice member 18 until the tips of the upper posts 23 snap into place on locking structure provided on the partition plate. Details of the cooperating structure for the lower support arm is shown in FIG. 5, while details of the upper post locking structure is shown in FIGS. 6, 7, and 8.
As shown in FIG. 5, a lower edge of the partition plate 14 is provided with a transversely extending flange 24 that is turned upwards. At a position below the motor 16 the flange 24 is provided with a pair of cutouts 25 leaving an upstanding tongue 26. A transverse slot 27 at the distal end of the support arm 22 fits over this tongue 26.
The support arm 22 also has a rib member 28 that slopes distally upwards from the slot 27. When the orifice member is rotated or rocked into position, the slot 27 and tongue 26 serve as a pivot, and the rib member 28 comes to lodge against the partition plate 14, snapping into place beneath a lug 29, formed as a lance or boss on the plate 14. Here, additional reinforcing flanges 30 support the rib 28 on the end of the support arm 22.
The locking structure for the upper posts 23 is shown in FIGS. 6, 7, and 8. The distal tip of the post 23 has a flat vertical face 31 and a stop portion 32 protruding distally a short distance beneath the face 31. A slot 33 extends along a longitudinal midline of the post from a short distance back from the tip, then down through the vertical face 31 and the stop 32. The slot 33 has a wide portion, i.e., a transverse cutout 34, on the face 31 a distance spaced above the stop 32. As shown also in FIG. 7, bent-out tabs 35 are formed at corresponding positions on the partition plate 14 above the fan motor 16. These tabs are in the form of fingers having notches 36 located on their side edges at a distance from the plate 14. When the orifice member is installed, the tabs 35 penetrate the transverse cutout 34, on the vertical face 31. Then, resilience in the unitary posts urges the posts to spring upwards, and the edges of the slots 36 of the tab lodge onto the narrower portion of the slot 33. The stops 32 lodge against the underside of the tab 35. Preferably, the stops 32 protrude distally an amount sufficient to bias against the partition plate. This attached arrangement is shown in FIG. 8.
It can be seen that these parts are assembled securely and reliably without resort to conventional fastening means. That is, in the construction no screws, bolts, nuts, or clips are needed. The assembly step can be carried out swiftly and economically, while achieving the highest levels of reliability and quality.
Terms of orientation, such as upper, lower, above or below, are meant to facilitate an understanding of the described invention, and not to limit the invention in any way to a particular orientation.
While this invention has been explained in detail with reference to a single embodiment, it should be understood that this invention is not limited only to that embodiment. Rather, many variations would present themselves to those of skill in the art without departing from the scope and spirit of this invention as defined in the appended claims: | A window type portable air conditioner has a partition plate and orifice plate designed to assemble by snapping together, eliminating the need for other parts or fasteners, while ensuring accurate orifice location. The orifice plate has integrally formed lower support arm and upper support posts. The partition plate has tongue and tab structure formed thereon to engage and interlock with receiving structure formed at the distal ends of the support arm and posts. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to the field of containers, and more particularly to the area of containers with a variable height storage area adapted to retain bulk particulate matter.
[0003] 2. Description of Related Art
[0004] Solid particulate matter such as grains, pet food, chemicals are often stored in large bin containers for incremental dispensing by a subject. Pet food, for example, is commonly available in dry food forms such as cereals which is stored in relatively large bin-type containers. This type of pet food is commonly referred to as kibble.
[0005] One problem with storing kibble and other like bulk particulate matter in a bin type container is that upon removal and depletion of the particulate matter from the bin, a person must progressively reach further into the container toward its bottom to access the remaining bulk material. This can be difficult for those with physical limitations, such back problems, arthritis, and nervous system disorders, making it difficult to bend or reach for objects. Reaching further into the bin each succeeding time can only be temporarily resolved by filling the bin. However, this is only a temporary solution because as the bin is depleted over time once again the same difficulties develop in removing material from the bin.
[0006] Therefore, a device that allows a person to withdraw bulk material from a container having a design that eliminates, or at least substantially reduces a person's need to bend or reach for material located towards the bottom of the container is needed and desired. It would be particularly beneficial if the container could be used for storing a variety of bulk material such as powdered laundry detergent, pet food, grains, and other foods such as beans, and snack chips. The container should also be available in numerous sizes and shapes.
SUMMARY OF THE INVENTION
[0007] The container of the present invention allows a user to scoop bulk material there from without the need to bend over or reach into a significant portion of the container as it is emptied. The container has a material containing pan wherein the height of the pan relative to the height of the container is determined by the weight of the material resting on the pan. To effectuate the ability to alter the pan height within the container, springs are provided to respond accordingly to the weight of material on the pan which thereby provides a force for pushing upward on the pan. If the weight on the pan is relatively great, for example, 40 pounds of dog food, then the downward force from the weight on the pan is greater than the upward force from the springs. Thereby, the pan is designed to be at the bottom portion of the container so the user is able to scoop out the pet food from the top of the storage container. If using the same container and the weight on the pan is relatively small, for example 5 pounds of dog food, then the downward force from the weight on the pan is less than the upward force from the springs and the pan is essentially closer to the top portion of the container thereby enabling the user to reach and scoop out the dog food from the top of the container.
[0008] The container can be used to store a variety of bulk particulate material such as powdered laundry detergent, pet food, grains, other foods such as beans, chips, or other bulk particulate food matter and is available in numerous sizes and shapes. If, for example, the container is to be used for detergent soap, then springs with the correct compression rating are used such that when the container is full of detergent soap, the pan is at the bottom of the container and when the container is relatively empty of detergent soap, then the pan is relatively close to the top of the container.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
[0010] FIG. 1 is an exploded view of a container with lift system in accordance with the present invention;
[0011] FIG. 2 is a perspective view of the material pan of the present invention;
[0012] FIG. 3 is a perspective view of an alternate embodiment of the present invention;
[0013] FIG. 4 is a perspective cross sectional view of an alternate embodiment of the present invention; and
[0014] FIG. 5 is a perspective cross sectional view of an alternate embodiment of the present invention.
DETAILED DESCRIPTION
[0015] In the descriptions that follow, like parts are marked throughout the specification and drawings with the same numerals, respectively. The drawing figures are not necessarily drawn to scale and certain figures may be shown in exaggerated or generalized form in the interest of clarity and conciseness.
[0016] As shown in FIG. 1 , container 102 comprises front wall 104 a , back wall 104 b , side wall 106 a , side wall 106 b , floor 136 , lid 108 , retainer ring 110 , material pan 112 , rubber gasket 114 , spring insert 116 , lower spring insert 142 , and springs 118 .
[0017] Front wall 104 a and back wall 104 b may be made of metal, plastic, rubber, or other similar rigid or semi-rigid material capable of supporting container 102 . By way of example and not of limitation, front wall 104 a and back wall 104 b in FIG. 1 are approximately 21 inches high and 21 inches wide. In other embodiments, the dimensions can change and such changes are apparent to one skilled in the art. Front wall 104 a and back wall 104 b have outside edges 119 a and 119 b , respectively, and inside edges 120 a and 120 b , respectively. Front wall 104 a and back wall 104 b are connected to side walls 106 a and 106 b.
[0018] Side walls 106 a and 106 b may be made of metal, plastic, rubber, or some other similar rigid or semi-rigid material capable of supporting container 102 . In the embodiment shown in FIG. 1 , side walls 106 a and 106 b are approximately 21 inches high and 15 inches wide. In other embodiments, the dimensions can change and such changes are known to one skilled in the art. Side walls 106 a and 106 b have outside edges 122 a and 122 b , respectively, and inside edges 124 a and 124 b , respectively. Inside edges 120 a , 120 b , 124 a , and 124 b define cavity 126 .
[0019] Cavity 126 has a top portion 128 and a bottom portion 130 . In use, cavity 126 contains material pan 112 , rubber gasket 114 , spring inserts 116 , lower spring inserts 142 , and springs 118 . Top portion 128 of cavity 126 contains retainer ring 110 .
[0020] Retainer ring 110 may be made of metal, plastic, rubber, or some other similar rigid or semi-rigid material and is secured to container 102 . Retainer ring 110 extends from inside edges 120 a , 120 b , 124 a and 124 b into top portion 128 of cavity 126 and prevents material pan 112 from extending past retainer ring 110 .
[0021] Material pan 112 is made of made of metal, plastic, rubber, or some other similar rigid or semi-rigid material and, as shown in FIG. 2 , has an upper portion 202 and a lower portion 204 . By way of example and not of limitation, in the embodiment shown in FIG. 2 , upper portion 202 is approximately 20 inches wide, 14 inches long and fits inside cavity 126 ( FIG. 1 ). In other embodiments, the dimensions can change and such changes are known to one skilled in the art. Upper portion 202 contains rubber gasket 114 .
[0022] Rubber gasket 114 surrounds upper portion 202 of material pan 112 such that a seal is made between inside edges 120 a , 120 b , 124 a and 124 b and upper portion 202 of material pan 112 . The seal may be a waterproof seal but is at least such that the contents in material pan 112 are prevented from spilling outside material pan 112 and into bottom portion 130 of cavity 126 .
[0023] Lower portion 204 of material pan 112 contains spring insert 116 . Spring insert 116 contains a cavity for housing spring 118 .
[0024] Spring 118 is a compression helical spring with about 39 active coils and a spring rate of approximately 1.125 lbs/sq inch such that the spring forces material pan 112 to contact retainer ring 110 when material pan 112 does not contain any bulk material. Spring 118 has a top 138 and a bottom 140 . Top 138 can fit inside spring insert 116 and is secured to lower portion 204 of material pan 112 by spring insert 116 . Spring 118 may be secured to material pan 112 by means other than spring insert 116 such as a groove, indention, or notch in material pan 112 or by the pressure spring 118 exerts on material pan 112 . Such other means to secure spring 118 to material pan 112 would be obvious to one skilled in the art.
[0025] Bottom 140 of spring 118 is secured to floor 136 by lower spring insert 142 . Spring 118 may be secured to floor 136 by means other than lower spring insert 142 such as a groove, indention, or notch in floor 136 or by the pressure spring 118 exerts on floor 136 . Such other means to secure spring 118 to floor 136 would be obvious to one skilled in the art. Floor 136 forms the base of container 102 and is attached to front wall 104 a , back wall 104 b , and side walls 106 a and 106 b.
[0026] In use 40 pounds of commercially available dog food is inserted into container 102 . The weight of the dog food compresses spring 118 such that material pan 112 is lowered into bottom portion 130 of cavity 126 . Rubber gasket 114 prevents any of the dog food from spilling into bottom portion 130 of cavity 126 .
[0027] Removable lid 108 may be secured to container 102 to prevent unwanted material and moisture from contacting the dog food. Removable lid 108 has lip 134 and may be placed on top portion 128 of cavity 126 such that lip 134 is in contact with outside edges 119 a , 119 b , 122 a , and 122 b . Removable lid 108 may be made of metal, plastic, rubber, or some other similar rigid or semi-rigid material and may be secured to container 102 by a snap closure or some other lid locking mechanism known in the art to secure a removable lid on a container and prevent unwanted substances from entering cavity 126 .
[0028] When dog food is removed from container 102 , the weight of the dog food contained within material pan 112 is reduced and spring 118 pushes material pan 112 towards top portion 128 of cavity 126 . Because material pan 112 is raised by spring 118 relative to the amount of dog food removed from container 102 , the dog food is always at the top of container 102 . When all or almost all of the dog food has been removed from container 102 , material pan 112 is in contact with retainer ring 110 and retainer ring 110 prevents compression spring 118 from pushing material pan 112 outside of cavity 126 .
[0029] FIG. 3 is an alternate embodiment of the present invention wherein the springs are attached to the top portion of the container instead of the bottom portion and shows container 402 , front wall 410 , back wall 404 , side wall 406 , material pan 412 , and channel 430 . Container 402 has a top portion 426 and a bottom portion 428 . FIG. 4 is a perspective cutaway view of container 402 cut along plane 302 shown in FIG. 3 .
[0030] As shown in FIG. 4 , container 402 has a top portion 426 and a bottom portion 428 , comprises front wall 410 , back wall 404 , side wall 406 , floor 408 , material pan 412 , and spring 414 . Spring 414 has an upper section 416 and a lower section 418 . Front wall 410 , back wall 404 , side wall 406 , floor 408 , and material pan 412 may be made of metal, plastic, rubber, or some other similar rigid or semi-rigid material.
[0031] Side wall 406 comprises outside wall 420 and inside wall 422 . Outside wall 420 and inside wall 422 define spring cavity 424 . Spring cavity 424 houses spring 414 . Upper section 416 of spring 414 is attached to top portion 426 of container 402 . Lower section 418 of spring 414 is attached to material pan 412 . Inside wall 422 contains channel 430 which is wide enough to accommodate at least a portion of material pan 412 so material pan can extend from one spring cavity 424 , to the spring cavity on the opposite side of container 402 .
[0032] Spring 414 is of sufficient strength to lift material pan 412 to the top portion 426 of container 402 when material pan 412 is relatively empty. However, when bulk material is added to material pan 412 , the weight causes spring 414 to stretch and material pan 412 to be lowered into bottom portion 428 of container 402 such that the bulk material is contained within and does not spill outside of container 402 . As shown in FIG. 4 , more than one spring 414 may be used.
[0033] FIG. 5 shows a perspective cutaway view of an alternate embodiment of the present invention. Container 602 is a drum container, such as a common 55 gallon drum container, and comprises wall 604 , floor 606 , removable lid 608 , retainer ring 610 , material pan 612 , rubber gasket 614 , spring inserts 616 , lower spring inserts 618 , and spring 620 .
[0034] Wall 604 is made of metal, plastic, rubber, or some other similar rigid or semi-rigid material and provides support for container 602 . Wall 604 has an outside edge 622 and an inside edge 624 . Inside edge 624 defines cavity 626 .
[0035] Cavity 626 has a top portion 628 and a bottom portion 630 . Cavity 626 contains material pan 612 , rubber gasket 614 , spring inserts 616 , lower spring inserts 618 , and springs 620 . Top portion 628 contains retainer ring 610 .
[0036] Retainer ring 610 may be made of metal, plastic, rubber, or some other similar rigid or semi-rigid material. Retainer ring 610 extends from inside edge 624 into top portion 628 of cavity 626 and prevents material pan 612 from extending past retainer ring 610 .
[0037] Material pan 612 may be made of metal, plastic, rubber, or some other similar semi-rigid material and has an upper portion 632 and a lower portion 634 . Rubber gasket 614 surrounds upper portion 632 of material pan 612 such that a seal is made between inside edge 624 and upper portion 632 of material pan 612 . The seal may be a waterproof seal but is at least such that the contents in material pan 612 are prevented from spilling outside material pan 612 and into bottom portion 630 of cavity 626 .
[0038] Lower portion 634 of material pan 612 contains spring insert 616 . Spring insert 616 houses spring 620 . Spring 620 is a compression helical spring with about 39 active coils and a spring rate of approximately 1.125 lbs/sq inch such that the spring forces material pan 612 to contact retainer ring 610 , when material pan 612 does not contain any bulk material. Spring 620 has a top 638 and a bottom 640 . Top 638 is secured to lower portion 634 of material pan 612 by spring insert 616 . Spring 620 may be secured to material pan 612 by means other than spring insert 616 such as a groove, indention, or notch in material pan 612 or by the pressure spring 620 exerts on material pan 612 . Such other means to secure spring 620 to material pan 612 would be obvious to one skilled in the art.
[0039] Bottom 640 is secured to floor 606 by lower spring insert 618 . Spring 620 may be secured to floor 606 by means other than lower spring insert 618 such as a groove, indention, or notch in floor 606 or by the pressure spring 620 exerts on floor 606 . Such other means to secure spring 620 to floor 606 would be obvious to one skilled in the art. Floor 606 forms the base of container 602 and is attached to wall 604 .
[0040] In use 40 pounds of commercially available dog food is inserted into container 602 . The weight of the dog food compresses spring 620 such that material pan 612 is lowered into bottom portion 630 of cavity 626 . Rubber gasket 614 prevents any of the dog food from spilling into bottom portion 630 of cavity 626 .
[0041] Removable lid 608 may be secured to container 602 to prevent unwanted material and moisture from contacting the dog food. Removable lid 608 is made of made of metal, plastic, rubber, or some other similar rigid or semi-rigid material and may be secured to container 602 by a snap closure or some other lid locking mechanism known in the art to secure a removable lid on a container and prevent unwanted substances from entering cavity 626 .
[0042] When dog food is removed from container 602 , the weight of the dog food contained within material pan 612 is reduced and spring 620 pushes material pan 612 towards top portion 628 of cavity 626 . Because material pan 612 is raised by spring 620 relative to the amount of dog food removed from container 602 , the dog food is always at the top of continuer 602 . When all or almost all of the dog food has been removed from the container, material pan 612 is in contact with retainer ring 610 and retainer ring 610 prevents spring 620 from pushing material 612 outside of cavity 626 .
[0043] While springs 118 , 418 , and 620 are shown as helical springs, it is understood by those skilled in the art that a suitable substitution may be made for the springs. One such embodiment (not shown) may use hydraulic chambers connected to a mechanical or electrical controlling device for effecting changes of height of the material pans 112 , 412 , and 612 within their respective containers.
[0044] Although the invention has been described with reference to one or more preferred embodiments, this description is not to be construed in a limiting sense. There is modification of the disclosed embodiments, as well as alternative embodiments of this invention, which will be apparent to persons of ordinary skill in the art, and the invention shall be viewed as limited only by reference to the following claims. For example, material other than dog food may be used in the container. If other material is used, then the spring ratio of the spring may have to be adjusted. Any necessary adjustments would be known to those skilled in the art. Also, the container does not have to be rectangular in shape, it may be square, oval, or any other shape. | The present invention allows a user to scoop material from a container without having to bend over when the container is empty. The container has a material containing pan wherein the height of the pan is determined by springs which respond to the weight of material on the pan. If the weight on the pan is relatively great, for example, 40 pounds of pet food, then the pan is at the bottom portion of the container and the user is able to scoop out the pet food from the top of the container. If the weight on the pan is relatively small, for example 5 pounds of pet food, then the pan is at the top portion of the container and the user is able to scoop out the dog food from the top of the container. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to apparatus for treating liquids and slurries by the use of a pulsed spark discharge between electrodes in a treatment vessel and, more particularly, to the purification of domestics, agricultural and industrial waters; sewage waste waters; industrial, chemical food processing and other toxic waste products; and the separation of dissolved sales and minerals, metals and other elements from liquids and slurries.
The increasing awareness of the need to treat liquid-like substances such as sewage, chemical and food-processing waste and other toxic waste products prior to their release into the surrounding environment has created a strong present interest in effective methods and apparatus for efficiently carrying out a purification process. One process described in U.S. Pat. No. 4,458,153 utilized the effects of a spark discharge produced between electrodes in combination with a localized magnetic field to alter the characteristics of confined liquid substances. Other investigations have resulted in limited volumes of liquid-waste being treated in a small confinement chamber, typically one liter or less, in which a spark discharge is established for a brief period. In this apparatus, a pair of electrodes are provided in the chamber with the pulsed energy from an external power source applied therebetween. The investigations have demonstrated that increased radiated power, shock waves and pressures in the vessel can be used to destroy micro-organisms in the liquid and effect purification thereof.
Results from spark discharge studies have been obtained using laboratory-size vessels to provide batch purification processing of small quantities of liquid waste. Primarily because of the energy requirements, the limited capacity of the treatment vessel and the use of batch treatment techniques, the spark discharge treatment method has not been commercially developed. Due consideration has not been given to the overall design of the confinement chamber so as to render it capable of use on a continuing basis for relatively large quantities of liquid waste. Furthermore, the energy consumption of known systems using a small confinement vessel is relatively large per unit of treated material. This characteristic is due in part to the lack of efficiency in the transfer of energy from the power source to the region between the exposed ends of the electrodes within the chamber.
In the confining vessel, the region between the electrode ends is the location of the spark discharge which generates the initial plasma channel. The transfer of energy to establish and expand the plasma channel is an important factor in generating the ultraviolet radiation, shock waves, electrohydraulic pressure and cavitation in the treatment vessel which produce the purification of the liquid waste. The amount of energy transferred to the plasma channel determines the amount of liquid waste that can be effectively treated in a single spark discharge for a particular designed chamber. Prior devices have been limited due to inefficient energy transfer and inadequate chamber design to the batch treatment of small quantities of liquid waste.
Accordingly, the present invention is directed to apparatus for treating liquid waste on a continuing basis wherein the efficiency of the energy transfer between power source and electrodes is improved. In addition, the treatment vessel of the apparatus is constructed to promote the effects produced by the spark discharge throughout the volume of liquid in the vessel. The combination of the features of the novel treatment vessel along with improvements in energy transfer permits treatment vessels of relatively large volume to be employed in the spark discharge treatment of liquid waste. Also, the present invention provides apparatus for continuing treatment of liquid waste without requiring lengthy interruptions in the movement of liquid waste material from a larger reservoir.
SUMMARY OF THE INVENTION
This invention is concerned with apparatus for treating liquid-like waste products by the use of a spark discharge occurring within a treatment vessel. The vessel is configured so that the liquid receives the benefits of the multiple effects of the spark discharge throughout a relatively large volume treatment vessel.
The apparatus includes a treatment vessel provided with input and output ports. Sealing means are located at the input and output ports and operate based on pressure differentials to permit a repetitive sequence of steps in the continuous operation of the apparatus. The treatment vessel has an inner surface which bounds the liquid treatment region and communicates with the input and output ports. The inner surface of the vessel includes a reflector section and a concentrator section. The reflector section is configured to distribute the produced effects to the concentrator section which promotes the treatment of the contents of the vessel.
Electrodes extend into the vessel with the tips thereof spaced adjacent the reflection section. All external pulse forming circuit is coupled to the electrodes for providing a series of voltage pulses between the electrodes. The spark discharge repetitively occurs between the electrodes in response to the application of voltage pulses therebetween. The discharge establishes a plasma in the liquid between the electrodes thereby creating a number of different effects throughout the treatment vessel. The effects include a plasma generated shock wave, short wavelength ultraviolet radiation and an electrohydraulic pressurization of the treatment vessel. These three produced effects combine to alter the characteristics of the liquid material within the treatment vessel to provide a purified liquid product.
The treatment vessel is provided with input and output ports with each port containing a sealing means for controlling the passage of liquid therethrough. The input port is normally coupled to a large volume reservoir which stores the untreated material. When the operation of the apparatus is initiated, material from the reservoir is urged under pressure into the treatment vessel through the input port. Control means is provided for regulating the supply of fluid to the input port and also for establishing the timing of the voltage pulses supplied to the electrodes. When the spark discharge occurs within the treatment vessel, the generation of the plasma between the electrodes produces multiple effects including a rapid increase in electrohydraulic pressure. The sealing means at the input and output ports are pressure responsive so that they seal the input and output ports during the time of treatment. When the increased pressure dissipates following treatment, the control means urges a new supply of untreated liquid into the treatment vessel through the input port and the treated material departs through the output port. The control means initiates the sequence of steps used in the repetitive process so that continual treatment of materials from the supply reservoir occurs.
The electrical conductivity of the plasma is a known constant established by ionization of the liquid adjacent the electrode tips. The average diameter of the plasma when first established can be measured so that for a particular electrode spacing, the average plasma impedance fails within a calculable range. The pulse forming network is provided with an impedance which is within the range of the impedance of the plasma channel so that energy is efficiently pumped into the plasma channel between the electrodes during the spark discharge. Thus, the matching of the impedances increases the peak power delivered to the plasma thereby enhancing the radiation from the plasma and the electrohydraulic pressuring of the liquid. The reflector section serves to direct the radiation and the shock wave produced into the concentrating section which distributes these treatment effects throughout the confinement chamber. As a result, it is possible to treat the liquid confined in a larger treatment vessel than heretofore possible and to affect this treatment with an increased energy efficiency.
Further features and advantages of the invention will become more readily apparent from the following detailed description of preferred embodiments thereof when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block schematic diagram showing the liquid flow path in partial section of a preferred embodiment of the invention.
FIG. 2 is an electrical schematic diagram of the pulse forming network of the embodiment of FIG. 1.
FIG. 3 is a series of wave forms showing the multiple effects generated within the treatment vessel of the embodiment of FIG. 1.
FIG. 4 is a cross-sectional view of a second embodiment of a treatment vessel suitable for use in connection with the embodiment of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, the apparatus includes a high strength treatment vessel 20 of approximately four liter capacity defining the volumetric region for receiving the liquid-like substance to be treated. The capacity of the vessel may be varied in accordance with the particular application without departing from the operating characteristics described herein. The term high strength is used herein to mean a high tensile, non-fatiguing metal alloy. The treatment vessel includes a reflector section 21 having a curved parabolic inner surface 23 which bounds and defines the upper portion of the liquid treatment region. While the preferred embodiment utilizes a parabolic curved surface 23 as a reflector, it is to be noted that a hemispherical inner surface may be utilized in other embodiments. Also, a mating concentrating section 22 is sealingly affixed thereto to form a unitary vessel and complete the volumetric treatment region. The inner surface 24 of the concentrator section which bounds the lower portion of the liquid treatment region is shown inwardly tapered. The volume available for liquid containment decreases in the concentrator with increasing distance from the reflector section. The concentrator section terminates at input port 31. An output port 35 laterally spaced from the electrode tips 30 is provided in the reflector section 21. In the embodiment shown, the tips were constructed of a metallic carbide for the high melting point and high impact resistance.
The treatment vessel 20 includes a central opening which receives an insulator plug 26 through which extend a pair of spaced electrodes 28, formed from a high temperature steel alloy. Each electrode 28 terminates in an electrode tip 30 separated by a spacing distance 29. As will later be explained, the spark discharge takes place across the spacing 29 between the ends of electrode tips 30. The external portions of the electrodes 28 are electrically coupled through switch means 16 to pulse forming network 14. The pulse forming network is coupled to the external power supply 11. A clock circuit 12 is provided to synchronize the operation of the circuit and its output is coupled to control circuit 15 which operates switch means 16 and gas valve 17.
The liquid-like substance 40 to be treated is shown in FIG. 1 as flowing from conduit 41 into reservoir 42. The substance is drawn from the reservoir 42 by pump means 43 connected to the bottom region of the reservoir and is transferred into a gas pressurizing chamber 45. While not necessary for all applications of the apparatus, the embodiment shown permits the liquid-like material contained in chamber 45 to have its dissolved gas content either increased or decreased by mechanical pumping means (not shown) coupled to valve 17. A gas supply 48 is connected to valve 17 so that compressed air or other gas contained therein at a higher pressure than the material in chamber 45 can be introduced into the chamber through the valve. A level sensor 49 is contained in the wall of chamber 45 with its output supplied back to a control circuit 15. If the level of liquid-like material in chamber 45 rises above the level sensor position 49, the valve 17 can be actuated to supply additional gas under pressure from supply 48 so that a nearly constant level of material can be maintained in chamber 45. Since the gas-liquid interface in chamber 45 is at a higher than ambient atmospheric pressure, additional gas is caused to be dissolved in the substance. When the material is transferred to the treatment vessel, the additional gas dissolved therein can be used to enhance one or more of the generated effects from the plasma discharge occurring in the treatment vessel. The liquid-like material is transferred under pressure from the chamber 45 through conduit 46 to input port 31 located at the base of the treatment vessel 20.
In the embodiment shown in FIG. 1, the treatment vessel generally comprises a lower concentrator section 22 having the input port 31 located therein and an upper reflector section 21 containing the output port 35. The input port 31 includes a valving mechanism shown as comprising seat 32 and ball 33. In the absence of internally generated pressure within the treatment vessel through the spark discharge between electrodes, the increased pressure of the liquid-like material in chamber 45 causes the ball 33 to be dislodged from seat 32 and the material of chamber 45 flows into and fills the treatment vessel 20. The output port 35 contains a normally biased open valve so that material in the chamber which has been previously subjected to the effects of a spark discharge is urged outwardly through the output port 35 into a retaining vessel 47. An output flow control valve 54 is shown located in the fluid line between output port 35 and vessel 47 to permit regulation of the output flow rate throughout a wide range of pressures established in chamber 45. As mentioned previously, valve 17 is used to vastly the pressure in the pressurizing chamber 45 in accordance with a signal from control circuit 15. In the embodiment shown, the control circuit provides a corresponding signal to valve 54 to regulate the flow rate from the treatment vessel.
The treated output flow from the vessel is shown as liquid 50 in vessel 47. The output port 35 contains a threaded valve seat 36, spring 37 and ball 39. A communicating channel 34 extends into the treatment volume of the vessel. When the liquid-like material is contained within the treatment vessel, the effects of the spark discharge between the electrodes includes an increase in pressure which drives the ball 33 down against seat 32 of the input port and also overcomes the bias of spring 37 to cause ball 39 to rest against seat 36 of the output port. Thus, the internal pressure during treatment is used to momentarily interrupt the regulated flow of fluid through the treatment vessel 20. While the particular valves shown are a gravity-fed valve at the input port of this concentrator section and a biased check valve at the output port, it is recognized that other types responsive to internally generated pressure can be employed if desired.
The treatment vessel 20 of FIG. 1 is machined in two parts, the reflector and concentrator sections, from a metal slug or rod. In the preferred embodiment, the reflector section 21 contains an inner surface which is paraboloid and of a diameter that is equal to the diameter of the adjacent portion of the treatment volume of the concentrator section 22. The insulator 26 with the electrodes 28 extending therethrough is centrally located in the reflector section with electrode tips 30 located at the focus of the parabolic curve. The concentrator section contains an inwardly tapered surface that extends 360° around the inner portion of the concentrator. The inner surface 24 which bounds the lower portion of the treatment volume is a surface of revolution about a vertical axis which provides a decrease in the cross-sectional area of the treatment volume with increasing distance from the electrode tips 30. The establishment of a spark discharge between the electrode tips 30 creates multiple effects through the creation of a plasma in a channel therebetween. It is important that these effects be transmitted throughout the bounded treatment volume and that all of the liquid-like material contained therein be subjected to the intense shock waves and pressure produced by the plasma as well as the radiation generated thereby. The failure to expose the entire volume of liquid to the full effects produced by the plasma may result in all output liquid 50 of generally unpredictable quality being passed from the treatment vessel.
The spark discharge generates a plasma in the channel between electrode tips. The plasma expands and launches a high velocity shock wave into the liquid-like substance contained within vessel 20. Also, at the same time the channel of plasma is established between the electrodes, an intense burst of high energy radiation is transmitted from the plasma channel throughout the entire treatment volume. This effect occurs due to the fact that the radiation generated is characterized by wavelengths short enough to penetrate both the liquid and the small particles contained in the liquid-like substances. Since the apparatus is effective with opaque liquid, the frequency of a substantial part of radiation transmitted is well-above the low energy portion of the ultraviolet spectrum. In the present case, these wavelengths approach the size of the wavelengths of radiation at the edge of the X-ray portion of the spectrum as a consequence of the plasma channel reaching a temperature of approximately 100,000 degrees K several microseconds after initiation of the spark discharge. As the plasma channel expands. The liquid-like material is further compressed and the electrohydraulic pressure increases substantially. In many cases, the pressure reaches 1,000 atmospheres in about 500 microseconds. The time required and pressure reached upon maximum expansion of the plasma channel is dependent on the amount of energy discharged into the plasma channel and the volume and configuration of the treatment region in the vessel. The self-actuating valves at the input and output ports immediately close in response to this electrohydraulic pressuring of the material to limit the pressure effects to only that liquid which is contained at that time within the treatment vessel. While this preferred embodiment uses check valves, other embodiment may be operated using either mechanical or electrical means synchronized to the flow rate through the treatment vessel to seal the input and output ports.
The spark discharge is generated from the output of a pulse generator which includes switch means 16, pulse forming network 14 and power supply 11. The pulse generator provides a high voltage, high current pulse of short duration to the pair of electrodes 28 thereby causing a breakdown in the liquid-like material residing in the volume between the electrode tips 30. The spark discharge occurs from one electrode tip to the other with a resultant plasma being formed in the volume therebetween. The plasma channel so formed generates multiple effects which are transmitted throughout the volume to alter the characteristics of the liquid-like material contained in the treatment vessel. The power supply 11 may include a step up transformer with a high voltage, three phase bridge rectifier to supply a charging current to the pulse forming network 14. Alternatively, a solid-state, high frequency inverter which can maintain unity power factor during the supplying of current to the pulse forming network can be employed. A variety of conventional transformer-rectifier charging means for network 14 are well known in the art.
The pulse forming network is charged to a preset voltage level by the charging current from the power supply and stores sufficient energy so that when the switch means 16 is closed, a pulse of electrical energy is provided to the electrodes 28 thereby causing the spark discharge therebetween. As shown in FIG. 1, control circuit 15 is provided to monitor the voltage level in the pulse forming network 14 and actuate switch means 16 only when the desired voltage level has been achieved. In addition, the control circuit receives the output signal from the fluid level sensing circuit and provides a corrective signal to valve 17 should there need to be a correction in the fluid level within the chamber 45. The clock signal from circuit 12 determines the rate of sampling of the voltage in the pulse forming network and can be used 10 synchronize sampling of other sensors utilized in this system as needed. The establishment of data sample rates for additional sensors if employed can be accomplished by conventional techniques.
The pulse forming network 14 is shown in further detail in the electrical schematic diagram of FIG. 2 along with switch means 16, the electrodes 28 and the power rail connection 51 thereto. The spark discharge and the plasma arc created thereby is shown as variable resistor 52 between electrodes 28. The pulse forming network 14 includes a number of capacitors 57 and inductors 59 with the inductors being coupled in series with the electrodes 28 and the capacitors 57 being coupled in parallel. The unidirectional current from the power supply 11 charges the capacitors 57 until the switch means 16 is actuated by a signal from the control circuit 15. At this moment, the energy stored in the capacitors is transferred to the electrodes through the switch means 16 and its internal inductance and resistance 61 and 62 respectively and the low inductance power rail connection 51 with its internal impedance. As a result, a spark discharge is developed between the electrode tips 30 creating a plasma channel in the liquid material between the electrodes. The transfer of energy occurs in the form of a pulse shown as the power pulse in FIG. 3. In the embodiment shown, the peak power level provided to the electrode circuit is in excess of one gigawatt during a period of 5 to 10 microseconds. The energy transfer must occur during this relatively short interval because the plasma channel expands and increases in volume and the high energy densities necessary to produce the effects relied upon for treatment of the liquid are difficult to obtain over longer periods.
The internal inductance 61 and resistance 62 of the switch means are minimized to reduce losses of power delivered to the electrodes. Similar care should be taken to minimize the inductive and resistive losses in the power rail connection 51. Maximum pulse power is attained in the plasma channel between the electrodes when the impedance of the pulse forming network is substantially matched to the average resistance 52 presented to the network 14 by the plasma established between the tips 30 of electrodes 28 during the power pulse period. The impedance during an interval of two to five microseconds after actuation of the switch 16 is used to determine the desired match. In the embodiment shown, the switch means 16 is preferably a triggered mercury-pool gas tube. The inductance 61 and resistance 62 associated therewith provide less than five percent of the corresponding value of inductance and resistance for the equivalent electrical circuit seen looking back from the electrodes 28. The contribution of the resistive effect of the power rail connection is minimal. In the case of the inductance associated therewith, its value may include a significant portion of the output inductance 59' of pulse forming network 14. Thus, the inductance 59' can be reduced in value by the computed amount of the inductance of the power interconnect if a substantial line length is necessary to provide power to the apparatus.
The characteristic impedance of the pulse forming network is a function of the square root of the network inductance divided by the network capacitance. The impedance of the plasma generated between the electrodes 28 is shown as variable resistor 52 and is a function of the electrode spacing which is 2.5 centimeters in the preferred embodiment, along with the diameter of the plasma channel established and the resistivity constant of a plasma. The constant is typically of the order of 12 milliohms per centimeter. The diameter of the plasma channel established increases as a function of the square root of the time taken from the initiation of the plasma. During the early formation of the plasma, in the first microsecond, its resistance decreases from several ohms into the 25 to 75 milliohm range which is the impedance range to be used in designing the pulse forming network. In operation, the pulse forming network acts as a higher impedance network during the initiation of the plasma. In order to provide the energy of between 10 to 100 kilojoules for the successful operation of the embodiment of FIG. 1, a power pulse width of approximately 10 microseconds is required. The equation for the pulse width of the discharge from the pulse forming network determines the acceptable values for the inductors 59 and the capacitors 57. The equation is T=2(L×C) 0 .5. The value of capacitance in the embodiment shown calculates to be about 135 microfarads. Thus, each paralleled capacitor 57 would have a value of one third that quantity. The inductance 59 is approximately 150 nanohenries so that each series inductor 59, 59' would be 50 nanohenries. This provides a characteristic impedance of the pulse forming network of about 34 milliohms. A pulse forming network 14 of the type shown in FIG. 1 when providing a 10,000 volt pulse stores in excess of 25 kilojoules.
In operation, the establishment of the plasma in the treatment vessel exposes the material contained therein to multiple effects as shown by the wave forms of FIG. 3. The waveforms are plotted in two distinct time domains. The first domain is from the initiation of the spark discharge and the creation of the plasma up to 25 microseconds. The second time domain is from 200 to 1,000 microseconds. During the first time domain, the effects generated are occurring simultaneously with the initiation of the plasma channel, or lag it slightly. The immediate direct effect generated by the plasma is a high intensity burst of radiation lasting somewhat than the duration of the pulse from the pulse forming network 14. The radiation occurs as a burst due to the highly ionized state of the material forming the plasma. The wavelength of the radiation resides in the near X-ray region. Radiation of this wavelength has the capability to penetrate the entire volume of the treatment vessel to cause oxidation of the liquid-like material contained therein. For the embodiment of FIG. 1, the radiation is equivalent to a black body radiating temperature of over 100,000 degrees K.
A second direct effect produced by the expanding plasma channel is that of the launching of a shock wave having an initial pressure peak of nearly one million atmospheres as it breaks away from the expanding plasma channel during the first few microseconds. The channel initially is formed with a diameter of 1 to 3 mm and expands to about 5 cm. As this supersonic wavefront propagates outward from the plasma channel, it is reflected and deflected by the treatment region boundaries as it propagates therethrough in a few hundreds of microseconds. During this period of shock wave propagation, an extremely high compressive component resides in its leading edge region. A comparable tensile component develops in its trailing edge region. This tensile strain produces a cavitation effect in the liquid-like substance which is found to be useful in the generation of free radicals and electrons from the material. The compressive component of the shock wave results in a fracturing of any suspended solids. In operation of the embodiment of FIG. 1, solid particles within the range of 0.1 to 1 millimeter in diameter have been converted into nearly micron size. Another effect of the shock wave is in the tearing apart or breaking down of large molecules and microorganisms. Also, the shock wave changes the solubility product of dissolved solids by means of the extreme pressure gradient travelling through the treatment vessel. Material experiencing the shock wave is first compressed then quickly decompressed with the extreme pressure collapse causing a change in the solubility product thereby promoting precipitation of dissolved solids and facilitating recovery from the treated material.
A further effect of the high pressure pulse plasma established within the treatment vessel is the development of an electrohydraulic compression of the entire contents of the treatment vessel. As the plasma channel expands into a bubble with time, its volume increases thereby compressing the liquid within the vessel. The kinetic energy of the expanding plasma channel or bubble is expended in cooling from the induction of liquid into the plasma bubble during expansion until a pressure equalization is reached between the plasma bubble and the electrohydraulic pressure developed within the reaction vessel. A typical pressure balance of 1,000 atmospheres is reached in approximately 500 microseconds from the initiation of the plasma. Any dissolved gasses in the liquid-like material during this period are reduced in volume causing their temperature to increase to the point where ionization occurs thereby resulting in further free radical and electron production. When the plasma bubble ultimately collapses due to a massive loss of energy through its large surface area, the potential energy stored in the pressurized liquid causes the liquid to rush in to fill the volume formerly occupied by the plasma bubble. As the hydraulic pressure rapidly collapses, a tensile force is induced on the liquid in the wake of this collapse producing further cavitation with its associated free radical and electron generation. As can be seen in FIG. 3, the production of free electron and free radicals occurs at several intervals and for significant lengths of time during the one millisecond interval shown.
The significance of the extensive production of free radicals and electrons can be described as follows. Free electrons are absorbed by cations, especially metallic cations low on the electromotive force series, thereby reducing the cations to their elemental or nascent state. This process has applicability in both mineral extraction and toxic waste extraction operations. Free radicals such as the hydroxyl (OH) - produced in large populations throughout the treatment vessel act as a very powerful oxidizing agent to convert molecules such as hydrocarbons, fluorocarbons and the like to chemically inert components. Furthermore, the biochemical oxygen demand (BOD) of waste water and contaminated waters is significantly reduced by this advanced oxidation.
In operation, the embodiment of FIG. 1 has been successfully employed to treat a variety of different waste materials. Results obtained with the treatment of a slaughterhouse effluent showed that the biochemical oxygen demand (BOD) was reduced greater than 99%, the chemical oxygen demand (COD) was reduced greater than 95% and the reduction of fecal coliform bacteria was greater than 99.9%,. Tests performed on trailer park sewage showed a BOD reduction greater than 73%, a COD reduction of greater than 38% and a fecal coliform reduction greater than 99.9%. Similar operation using municipal sewage showed a BOD reduction of 82%, and a fecal coliform reduction greater than 99.95%. These results point out the ability of the present apparatus to render inactive contained microorganisms, oxidize bioactive content and reduce metallic cations in liquid materials. In addition, tests of the present apparatus have shown that metals can be extracted from solution and recovered by settling in the output reservoir.
An additional embodiment of the treatment vessel used in the practice of the present invention is shown in FIG. 4. The reflector section 21 of the treatment vessel is similar in all respects to its counterpart shown in FIG. 1. The concentrator section 72 in FIG. 4 differs significantly from the embodiment of FIG. 1 in that it has a straight external wall section. As mentioned previously, the treatment vessel of FIG. 1 is machined from a metal slug or rod. However, the concentrator section of FIG. 4 is formed from large diameter straight walled tube stock which results in a substantial cost saving in construction. A separate shock wave deflection member 73 is centrally located in the treatment vessel to ensure that the shock wave generated by the establishment of the plasma propagates throughout the material contained in the vessel. The curvature of insert 73 accomplishes the same result as the curved or inwardly tapered walls of the concentrated section 22 in that the liquid treatment region decreases in cross-sectional area and unit volume with increasing distance from the electrode tips 30. The deflector is tapered in cross section as shown in FIG. 4. The bottom surface 75 of the deflector 73 is affixed to the base plate 78. Lateral communicating channels 74 are formed in the deflector above the bottom surface 75. The channels 74 communicate with and extend laterally from the input port 31 into the treatment region of the vessel. The valve seat 32 receives ball 33 to effect closure of the input port 31 when the pressure increases due to treatment of the contained material. A receiving depression 76 is formed in the adjacent portion of the insert to permit the ball 33 to clear the communicating channels 74 during the input of material into the vessel. The discussion of the effects produced by the high pressure pulse from the plasma established in the reflector section and transmitted downwardly throughout the concentrator section applies to both the embodiments of FIG. 1 and FIG. 4. The tendency for the effects to dissipate as the distance from the electrode tips increases is countered by the compensation provided by the inwardly tapered wall 24 of the embodiment of FIG. 1 and the generally conical shape of the deflector insert 73 of the embodiment of FIG. 4. The treatment of the liquid-like material contained in the vessels of both embodiments is the same and the wave forms of the effects shown in FIG. 3 apply to the effects occurring in both forms of treatment vessel.
While the above description has referred to particular embodiments of the invention, it is to be noted that many modifications and variations may be made therein without departing from the scope of the invention as claimed. | Apparatus for purifying confined liquids and slurries by means of a spark discharge wherein the inner surface of the treatment vessel is designed to include a reflector section adjacent to a pair of electrodes and a concentrating section for intensifying the shock wave generated by the discharge between the electrodes. An external power source is coupled through a pulse forming network to the electrodes. The network is impedance matched to the impedance of the plasma arc generated between the electrodes to provide a high power pulse to the electrodes. The establishment of the plasma produces an extremely high pressure shock wave, u.v. radiation fringing on X-ray and electrohydraulic pressurization to alter the characteristics of the liquid therein. | 2 |
The present application claims the benefit of U.S. Provisional Application Ser. No. 60/312,704, filed Aug. 16, 2001, pending.
FIELD OF THE INVENTION
The invention relates to methods of making microcapsules and microcapsules comprising a core material and a shell material with substantially different dielectric constants and dissipation factors. Exposure to appropriate electromagnetic energy selectively (a) heats the core material with the higher dielectric constant and dissipation factor, directly or indirectly fusing the shell material and forming microcapsules, or (b) hardens polymerized shell material, which has a high dielectric constant and dissipation factor.
BACKGROUND
Most current microencapsulation methods are used to produce a uniform coating on an irregular shaped particle. Such methods typically require relatively complex equipment and/or a substantial input of labor. Such methods typically are very expensive. Simpler, less expensive microencapsulation methods are needed for encapsulating core materials having relatively non-uniform shapes.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a method of microencapsulation comprising:
providing core material effective to absorb electromagnetic energy at a given wavelength and frequency; providing shell material ineffective to absorb electromagnetic energy at said given wavelength and frequency; forming a precursor mixture comprising said core material and said shell material; and exposing said precursor mixture to said electromagnetic energy at a power and for a time effective to microencapsulate said core material with said shell material.
In another aspect, the invention provides a method of microencapsulation comprising:
providing a core material having a first dielectric constant and a first dissipation factor; providing a shell material having a second dielectric constant that is substantially different than said first dielectric constant and having a second dissipation factor that is substantially different than said first dissipation factor; forming a precursor mixture comprising said core material and said shell material; exposing said precursor mixture to electromagnetic energy under conditions effective to microencapsulate said core material with said shell material.
In a preferred embodiment, the second dielectric constant is a magnitude or more different than the first dielectric constant, and the second dissipation factor is a magnitude or more different than the first dissipation factor.
In one embodiment, the second dielectric constant is substantially less than the first dielectric constant and the second dissipation factor is substantially less than the first dissipation factor. Preferably, “substantially less than” is a magnitude or more less than. In this embodiment, said “exposing” heats the core material and causes fusing of the shell material immediately adjacent to the heated core material. The core material preferably comprises particles having an average diameter x. The shell materials preferably have an average diameter of about 0.1x, more preferably 0.01x.
In another embodiment, the second dielectric constant is substantially greater than the first dielectric constant and the second dissipation factor is substantially greater than the first dissipation factor. Preferably, “substantially greater than” is a magnitude or more greater than. In this embodiment, exposing the precursor mixture to electromagnetic energy preferably induces polymerization of the shell material.
In another aspect, the invention provides microcapsules comprising a core material effective to absorb electromagnetic energy at a given wavelength and frequency and a shell material that is ineffective to absorb said electromagnetic energy.
In another aspect, the invention provides microcapsules comprising a core material having a first dielectric constant and a first dissipation factor encapsulated by a shell material having a second dielectric constant and a second dissipation factor. The first dielectric constant and the first dissipation factor are substantially different than, preferably at least a magnitude different than, the second dielectric constant and the second dissipation factor, respectively.
In another aspect, the invention provides microcapsules comprising a core material having a first dielectric constant and a first dissipation factor encapsulated by a shell material. The shell material has a second dielectric constant and a second dissipation factor less than said first dielectric constant and said first dissipation factor, respectively.
In yet another aspect, the invention provides microcapsules comprising a core material having a first dielectric constant and a first dissipation factor encapsulated by a shell material having a second dielectric constant and a second dissipation factor. The second dielectric constant and the second dissipation factor are greater than the first dielectric constant and the first dissipation factor, respectively.
DETAILED DESCRIPTION OF THE FIGURES
FIG. 1 is an optical micrograph of the microcapsules formed in Example 1 after two minutes of microwave exposure in a 600 W microwave oven.
FIG. 2 is an optical micrograph of the sharp edges of the microcapsules of FIG. 1 showing efficient coating of the sharp edges of the TPP/carbon black particle.
FIG. 3 is a graph of the temperature versus time during electromagnetic heating at 2.45 GHz of pure H 2 O, pure hydroxyethylmethacrylate, pure acrylic acid, and pure methacrylic acid, respectively.
FIG. 4 is a graph of temperature versus time during electromagnetic heating at 2.45 GHz of aqueous solutions of acrylic acid, hydroxyethylmethacrylate, and methacrylic acid, respectively.
FIG. 5 is an optical micrograph of the microcapsules formed in Example 4.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides simple, efficient, and relatively inexpensive methods for forming microcapsules. The methods of the present invention use electromagnetic energy to form microcapsules from a core material having a “first” dielectric constant and a “first” dissipation factor, and a shell material having a “second” dielectric constant and a “second” dissipation factor. The first dielectric constant is “substantially different” than the second dielectric constant and the first dissipation factor is “substantially different” than the second dissipation factor. As used herein, the term “substantially different” is defined as a difference sufficiently great to permit microcapsules to form under the conditions of operation. Preferably, the difference between the first and second dielectric constant and the first and second dissipation factor is about one magnitude or more.
Microwaves interact with materials through electric and magnetic fields generated in the wave guide. Materials, which absorb energy from an electromagnetic (EM) field, can be heated by exposure to such a field. The absorption of electromagnetic energy also may drive a reaction, such as a polymerization reaction. The selective microwave absorption depends on the power density of the EM field and on the absorptive characteristics of the materials, as defined by the complex dielectric constant or dissipation factor (loss tangent). Absorption of microwave energy is high when the dissipation factor or loss tangent is high. The loss tangent (tan δ) is defined as:
tan δ = ε ″ ε ′
wherein ε*=jε″+e′ is the complex dielectric constant.
Microwave heating creates non-uniform thermal or energy absorption gradients which, in general, are a disadvantage. In the present process, the formation of non-uniform thermal or energy absorption gradients helps in inducing a selective absorption of energy either by the core material immediately adjacent to the shell material, or by the shell material itself. The result is microcapsules of the core material bearing a coating of the fused or polymerized shell material.
With appropriate process control on the amount of microwave energy supplied, appropriate wave guide design, and suitable selection of core and shell ingredients, the invention offers unique methods to coat materials of non-uniform shapes. The methods require only localized heating and therefore require a lower net temperature increase in the substrate. The methods have improved reaction specificity. The electromagnetic energy can be delivered rapidly at a specific time and place. The method provides increased processing speed, high coating efficiency, and the ability to prepare microcapsules with different payloads. Although batch, the methods are inexpensive because of short processing time and the ability to handle high production volumes.
Higher Dielectric Characteristics Core Material
In a preferred embodiment, the second dielectric constant and the second dissipation factor (of the shell material) are substantially less than, preferably a magnitude or more less than the first dielectric constant and the first dissipation factor (of the core material). In this embodiment, the core material either inherently has a relatively high “first” dielectric constant and a relatively high “first” dissipation factor, or contains one or more absorption enhancer(s) to increase the absorption of electromagnetic energy by the core material. The core material, alone, or in combination with one or more absorption enhancer(s) and/or one or more surface wetting agent(s), is mixed with a shell material that has a relatively low dielectric constant. The mixture is exposed to electromagnetic energy at a wavelength and frequency that are ineffective to heat the shell material, but that are effective to heat the core material and to induce melting of the shell material immediately adjacent to and surrounding the core material. Upon cooling, the previously melted shell material forms a fused, intact shell around the core material. The remaining shell material may be simply sieved or washed away, for example by density separation, leaving the resulting microcapsules.
Because water absorbs microwave energy effectively at 2.456 Hz, suitable core materials with a relatively high dielectric constant and a relatively high dissipation factor include, but are not necessarily limited to materials that comprise water, including, but not necessarily limited to salts, hydrates, oxides, water soluble materials, water absorbing materials, and hydrophilic materials. The purity of the compound and the amount of water present may influence the loss factor and microwave frequency of absorption, thus playing an important role during the microencapsulation process.
Specific examples of suitable core materials with a relatively high dielectric constant include, but are not necessarily limited to alumina, acidulants, citric acid, ascorbic acid, antiperspirants, solid bleaches, coffee solids, fruits, nuts, leavening agents, oxidizers, pigments, sodium bicarbonate, sweeteners, salts, activated carbon, pesticides, fungicides, fumigants, seeds, antiperspirants, bleaches, deodorants, inks, active metals, catalysts, curing agents, chemoluminence agents, corrosion inhibitors, deodorants, flame retardants, organometallics, phase change materials, curing agents, sealants, and resins.
It is not always necessary to mix a core material with a relatively high dielectric constant and a relatively high dissipation factor with an absorption enhancer. However, depending upon the core material and the shell material, it may be desirable to use one or more absorption enhancer(s) to increase absorption of electromagnetic energy by the core material. A variety of absorption enhancers may be used, including but not necessarily limited to chlorides, carbonates, nitrates, phosphates, carbon black, silicates, sodium silicates, calcium silicates, CABOSIL, silica aerogels, silica, silicon dioxides, talc, starches, maltodextrins, mica, bentonite, and other clay particles. Preferred absorption enhancers include, but are not necessarily limited to carbon black, talc, and silicates. The excess of core material to absorption enhancer is at least about 2:1, preferably 10:1, more preferably about 20:1.
One or more absorption enhancer(s) may be used to increase the absorption of electromagnetic energy throughout a given core material. Or, the absorption enhancer(s) may be used to increase absorption of electromagnetic energy immediately adjacent to the shell material. In order to accomplish this, spheronization preferably is conducted. “Spheronization” is a method by which micronized particles of absorption enhancer physically adhere onto the core particle by powder blending, semi-wet, or wet blending methods, including but not necessarily limited to ball-mill mixing, impaction, or compressive compaction. If an absorption enhancer is used, the absorption enhancer may be mixed with a surface wetting agent to provide improved surface adhesion to the core particle and/or to increase the efficiency of the spheronization process. Suitable wetting agents include, but are not necessarily limited to anionic, cationic, or non-ionic surfactants. Examples of suitable wetting agents include, but are not necessarily limited to sodium dodecyl sulphate, PLURONICS™, TWEENS™, SPANS™, phospholipids, and the like. Where an absorption enhancer is used, the core material is mixed with the absorption enhancer. After adequate mixing, by kneading, hand mixing, dough mixing, powder blending, or ball-mixing techniques, the mixture of absorption enhancer and core material is sieved to remove excess absorption enhancer, preferably carbon black.
The core material is mixed with an excess of suitable shell material, preferably a micronized shell material. Where the core material has been spheronized, the sieved mixture is added to an excess of the shell material. The ratio of sieved mixture to shell material is about 1:5, preferably about 1:10, more preferably about 1:100 or greater. The particles of core material should be well dispersed in the shell material.
Suitable shell materials preferably exhibit a “sharp” phase transition, i.e., melt point, gel point, softening point crystallization point, glass transition temperature, and the like. In this context, the term “sharp” means that the shell system exhibits a change in specific heat and exhibits a latent heat (Δλ) or change in enthalpy of polymerization (ΔH p ). The shell particles preferably are much smaller than the core particles, preferably only 0.1x, more preferably only 0.01x, where x is the average diameter of the core particles. Preferred shell particles are micronized, and have an average diameter of from about 1 μm to about 500 μm. Micronized materials are available from source companies or can be produced by conventional spray congealing methods.
Suitable shell materials with a relatively low dielectric constant and a relatively low dissipation factor include, but are not necessarily limited to waxes, fats, resins, and low melting polymers. Examples of suitable waxes include, but are not necessarily limited to paraffins, polyalkylenes, polyakylene glycols, polyalkylene oxides, edible waxes, mineral wax, shellac, and other natural waxes. Examples of suitable fats include, but are not necessarily limited to monoglycerides, diglycerides, triglycerides, lipids, fatty acids, and fatty alcohols. Examples of low melting polymers include, but are not necessarily limited to polyethylene oxide, polyethylene glycol, polyethylene, polypropylene, and polytetrafluoroethylene. Preferably, the shell materials are micronized, exhibit a sharp melt point, and do not absorb the electromagnetic energy used to heat the core material.
After mixing the core material with an excess of shell material, the mixture is then exposed to electromagnetic energy to “cure” the mixture and to microencapsulate the core material. The electromagnetic field produces heat by means of the dielectric loss properties of the core material. The use of an electromagnetic field having substantially any frequency or substantially any wavelength should operate according to the present invention; however, certain frequencies or wavelengths will be preferred in certain circumstances, as outlined herein.
Where the core material has the relatively higher dielectric constant and the relatively higher dissipation factor, a preferred frequency range heats a selected core material but the intensity of heating is localized. In other words, the absorption intensity is sufficiently high to cause the micronized shell material immediately adjacent to the core material to fuse, leaving the remainder of the micronized shell material in micronized form.
The preferred frequency of operation depends on the absorption efficiency of the core so that the first dielectric constant and the first dissipation factor are maximized at that specific frequency range. The frequency dependence on heating is also influenced by the size of the core particle. When the size of the core particle is small, shorter wavelengths of microwave energy may be required for effective localized heating by Marangoni's dissipation of the core particle that has a high dielectric constant and dissipation factor. Preferably, the wavelength of the electromagnetic wave should be less than the largest dimension of the core particle, most preferably less than 0.1x of the size of the core. In such a case, energy absorption occurs by Marangoni's heat dissipation.
The electromagnetic field may be used to quickly raise the temperature of the core material to a desired point, and then to maintain the core material at that temperature for the desired “cure” period.
Preferred electromagnetic energy sources for use in this embodiment have a frequency region selected from the group consisting of a millimeter wave region and a microwave region. A millimeter wave energy source has a frequency in the range of from about 30 GHz to about 300 GHz, more preferably in the range of from about 30 GHz to about 50 GHz. A microwave energy source has a frequency in the range of from about 0.5 GHz to about 30 GHz, more preferably in the range of from about 1 GHz to about 10 GHz. The energy source preferably has a power in the range of from about 250 W to about 5 kW, most preferably in the range of from about 500 kW to about 1500 kW.
The “fusion time” for a given mixture is defined as the period of time required to induce fusion of the micronized shell material immediately adjacent to the core material in the mixture and to produce a continuous shell of fused material around the core material. The “fusion time” will depend on the type of core material, the electromagnetic energy source and its power, the shell material, absorption efficiency of the particle and wave guide design, and other reaction conditions. Suitable “fusion time” periods are in the range of from about 2 seconds to about 500 seconds, preferably in the range of from about 10 seconds to about 100 seconds, and most preferably in the range of from about 20 seconds to about 60 seconds.
Lower Dielectric Characteristic Core Material
Alternately, a core material that has a relatively low dielectric constant and a relatively low dissipation factor is mixed with a shell or monomer material that polymerizes to form a shell which has a relatively high dielectric constant and a relatively high dissipation factor. In this case, the mixture is exposed to electromagnetic energy at a wavelength and frequency that harden polymerized shell material adsorbed to the surface of emulsified droplets of core material. The polymerized shell material forms a fused, intact shell around the core material. The remaining shell material may be simply washed away, leaving the resulting microcapsules.
According to a preferred embodiment, a “precursor mixture” to be exposed to electromagnetic energy is prepared by producing an emulsion or suspension of the core material in an immiscible solvent. The emulsion or suspension may be in a hydrophilic solvent or a hydrophobic solvent. The type of solvent used will depend upon the miscibility of the core material. Preferred solvents are hydrophilic and include, but are not necessarily limited to water, aqueous solutions, N-methyl pyrrolidone, acetone, methyl ethyl ketone, methyl isobutyl ketone, heptanol, and octanol. The use of an aqueous solution of increases the efficiency of absorption of microwave energy. In a preferred embodiment, the solvent is aqueous, and one or more shell monomers/precursor(s) which are miscible with the aqueous solvent are added to the emulsion/suspension to form a “precursor mixture.” Examples of suitable water-miscible monomeric shell materials include, but are not necessarily limited to styrene oxide, acrylic acid, methacrylic acid, glycols, and acrylate monomers. Most preferred shell materials are acrylic acid, methyacrylic acid, and acrylate monomers. The “precursor mixture” may contain a polymerization catalyst. In a preferred embodiment, the polymerization catalyst is a weak acid or base which alters the pH of the solution, thereby accelerating the polymerization reaction. Without limiting the invention to a particular theory of operation, it is believed that, as it polymerizes, the polymerizing shell material becomes increasingly less susceptible to microwave absorption. As polymerization occurs, phase separation is induced by the like interactions, which allows deposition of the formed polymer onto the surface of the core droplets. Exposure of the mixture to electromagnetic energy accelerates polymerization and hardens the adsorbed polymeric shell material, completing the formation of the microcapsules. A cross-linking agent may be added before application of microwave energy.
Preferred electromagnetic energy sources for use in this embodiment are the same as previously described. The following microwave heating rates are expected for the following monomers at the following concentrations:
Microwave
Concentration
heating
Monomer
(vol. %)
Rate (J/s)
Acrylic Acid
25
14
40
30.6
50
32.6
60
27.3
75
14.7
100
2.0
50 in conc. HCl
17.8
50 in 50% HCl
13.6
75 in conc. HCl
32.6
2-Hydroxyethyl
25
19.7
Methacrylate
50
32.1
75
23.7
100
17.6
Methacrylic Acid
25
12.6
50
24.0
75
10.1
100
0.9
Deionized water
100
5.8
The “hardening time” for a given shell material is defined as the period of time that a polymerization mixture must be exposed to electromagnetic energy in order to produce a hardened, continuous shell of hard polymer around the core material. The “hardening time” will depend on the type of core material, the electromagnetic energy source and its power, the shell material, absorption efficiency of the particle and wave guide design, and other reaction conditions. Suitable “hardening times” are from about 10 seconds to about 500 seconds, preferably in the range of from about 20 seconds to about 100 seconds, and most preferably in the range of from about 30 seconds to about 60 seconds.
The invention will be better understood with reference to the following examples, which are illustrative only, and should not be construed as limiting the present invention to any particular embodiment.
EXAMPLE 1
An organic catalyst, quaternary phosphonium salts (TPP, Sigma), was selected as a core. The TPP initially was mixed with carbon black. Spheronization with carbon black was conducted by ball-milling to provide uniform surface adhesion to the catalyst surface. In a simplified experiment, TPP was well mixed with carbon black in a ratio of 3:1 using a spatula. After adequate mixing, the mixture was sieved to remove the excess carbon black. The sieved TPP/carbon black mixture was later added to microcrystalline mineral wax (Petrolite™ C-1035) in the ratio of 1:5 such that the particles were well dispersed in the micronized wax. The resultant mixture was exposed to microwave energy in a conventional microwave oven (600 W) at full power for 2 minutes. The resulting microcapsules were observed under microscope to exhibit coated sharp edges of uniform thickness of from about 10 μm to about 20 μm.
EXAMPLE 2
10 g of citric acid crystals obtained from Sigma, having an approximate particle size ranging from about 250 μm to about 1000 μm, are added to polyethylene wax (POLYWAX™ 500) at a ratio of 1:4. The particles of acidulant are well dispersed in the micronized wax. The resultant mixture is exposed to microwave energy in a conventional microwave oven (750 W) at full power for about 3.5 minutes. The resulting microcapsules are observed under the microscope to exhibit coated sharp edges of fused wax, and complete encapsulation.
EXAMPLE 3
Type A-5 alumina (Sigma) is dispersed in 10 mL of SPAN 80 to improve surface wetting characteristics. Excess SPAN 80 is filtered in a Buckner's funnel to form a cake. The resultant cake is blended with ULTRAFLEX WHITE (Petrolite) microcrystalline wax at a ratio of 1:20 to obtain a dry, free-flowing powder. The resultant mixture is subjected to a conventional 750 W microwave oven for period of about 1 minute. Microspheres are separated upon subsequent washing in water. The encapsulated alumina settles at the bottom, while excess wax floats to the top. The resultant capsules are observed under a microscope to exhibit several alumina particles in one microsphere. All microspheres are well coated; however, the particles are not spherical.
EXAMPLE 4
A 100 g. mixture of 5% wt hydroxymethacrylate (Fischer Scientific) in water was prepared. Methyl ethyl ketone (MEK) Peroxide at 1% concentration and 0.5% ethyl glycol dimethacrylate (EGDMA) was added as an initiator and cross-linking agent, respectively. The resultant solution was then redispersed in silicon fluid (200 cP) and subjected to 750 W microwave heating for 5 minutes. Microbeads were prepared in size ranging from about 10 μm to 50 μm. The results are shown in FIGS. 3 and 4 .
Persons of ordinary skill in the art will recognize that many modifications may be made to the present invention without departing from the spirit and scope of the present invention. The embodiment described herein is meant to be illustrative only and should not be taken as limiting the invention, which is defined in the claims. | Methods of making microcapsules and microcapsules comprising a core material and a shell material with substantially different dielectric constants and dissipation factors. Exposure to appropriate electromagnetic energy selectively (a) heats the core material with the higher dielectric constant and dissipation factor, directly or indirectly fusing the shell material and forming microcapsules, or (b) hardens polymerized shell material, which has a high dielectric constant and dissipation factor. | 8 |
FIELD OF THE INVENTION
The present invention relates to a garment including a ventilated area between ventilating openings in respective inner and outer layers of the garment in which moisture accumulated in the ventilated area is arranged to be drained externally of the garment through a drain opening while ventilating air is permitted to flow through the ventilated area between the ventilating openings in the inner and outer layers.
BACKGROUND
In various outdoor activities, it is known to provide outerwear which protects the wearer from the weather. Protecting the wearer from the weather however limits the breathability of the garment and accordingly it is known to provide various forms of ventilation to the garment as described in prior U.S. Pat. No. 7,284,282 by Bay; U.S. Pat. No. 6,085,353 by van der Sleesen; U.S. Pat. No. 5,845,336 by Golde; and U.S. Pat. No. 6,263,510 by Bay et al. In each instance, the ventilation requires a large portion of the garment to incorporate multiple layers for ventilation between the layers resulting in a costly construction simply for the purpose of ventilation. Furthermore, none of the prior art discloses suitable means for blocking moisture from precipitation in reaching the user when the vents are in an open position. Accordingly, the vents are only intended to be open when there is no precipitation, however, when precipitation is present the wearer is prevented from ventilating the garment without becoming wet.
US patent application 2008/0184454 by Collier discloses a further variation of a vented apparel in which ventilation openings in inner and outer layers are offset from one another which provides some resistance to moisture penetrating from the outer layer to the inner layer. Even if moisture is not directly transmitted through to the user however there is no means to prevent user contact with the inner layer once the inner layer becomes saturated with moisture so that the user would typically still become wet if the vent is in an open condition during precipitation.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a ventilated garment comprising:
a shell arranged to be worn about a portion of a body of a user;
an auxiliary layer attached about a periphery thereof to one of an inner surface or an outer surface of the shell so as to define a ventilated portion of the shell;
an exterior opening formed in an outermost one of the auxiliary layer and the ventilated portion of the shell;
a fastener associated with the exterior opening and being arranged to be operable between an open position in which the exterior opening is substantially unobstructed and a closed position in which the exterior opening is closed;
a drain opening formed in the outermost one of the auxiliary layer and the ventilated portion of the shell adjacent a lowermost portion of the periphery of the auxiliary layer;
at least one ventilating opening formed in an innermost one of the auxiliary layer and the ventilated portion of the shell such that a lowermost edge of said at least one ventilating opening is spaced above said lowermost portion of the periphery of the auxiliary layer;
a mesh layer supported between the ventilated portion of the shell and the auxiliary layer such that ventilating air can only reach said at least one ventilating opening from the exterior opening by passing through the mesh layer.
The use of a mesh layer between the auxiliary layer and the shell permits snow and the like to be trapped between the mesh layer and the outermost layer for subsequent draining through the drain opening also in the outermost layer. The use of an additional innermost layer spanning the inner side of the mesh layer assists in minimizing user contact with the mesh layer so that even when the mesh layer becomes saturated with moisture, the contact of the innermost layer with the user is minimized, thus minimizing the transfer of the moisture to the inner clothing layers of the user.
Preferably a bottom end of the periphery of the auxiliary layer is sloped downwardly towards the drain opening.
The drain opening may comprise a reinforced eyelet mounted in the outermost one of the auxiliary layer and the ventilated portion of the shell.
There may be provided a plurality of ventilating openings at spaced apart positions in the innermost one of the auxiliary layer and the ventilated portion of the shell.
The ventilating openings may be substantially aligned with the exterior opening such that the ventilating openings and the exterior opening overlap one another for more direct ventilation therethrough.
Alternatively, the ventilating openings may be offset from the exterior opening such that the ventilating openings and the exterior opening do not overlap one another to provide greater resistance to water penetration therethrough. In this instance, the ventilating opening may be above the exterior opening.
The innermost one of the auxiliary layer and the ventilated portion of the shell preferably comprises a panel of material such that the ventilating opening comprises a punched opening in the panel. In this manner, the panel surrounding the ventilating opening supports the ventilating opening to remain in a fully open condition.
Preferably the ventilating aperture is spaced above the lowermost portion of the periphery of the auxiliary layer.
Preferably the ventilating aperture occupies less than half of a total area of the panel of material forming the innermost one of the auxiliary layer and the ventilated portion of the shell.
When there is provided a plurality of ventilating openings at spaced apart positions from one another, preferably the mesh layer comprises a single mesh panel spanning the plurality of openings which is only secured about a peripheral edge of the mesh layer relative to the shell and the auxiliary layer.
Preferably the mesh layer comprises a mesh material having mesh openings which are arranged to prevent passage of snowflakes therethrough.
The mesh layer may include a hydrophobic coating thereon.
In one embodiment, the peripheral edge of the mesh layer is secured to the shell adjacent to the periphery of the auxiliary layer.
Alternatively, the peripheral edge of the mesh layer may be secured about a periphery of the exterior opening. In this instance, the mesh layer may comprise a mesh panel spanning an area which is greater than an area of the exterior opening in the open position such that the mesh panel defines a lower trough portion between the shell and the auxiliary layer below the exterior opening.
In a preferred embodiment, the auxiliary layer is attached to the inner surface of the shell such that the exterior opening and the drain opening are located in the ventilated portion of the shell and the ventilating openings are located in the auxiliary layer.
Alternatively, the auxiliary layer may be attached to the outer surface of the shell such that the exterior opening and the drawing opening are located in the auxiliary layer and the ventilating openings are located in the ventilated portion of the shell.
Preferably a strip of sealing material overlaps the periphery of the auxiliary layer so as to be in sealing engagement with both the shell and the auxiliary layer about a full perimeter of the auxiliary layer.
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a first embodiment of the ventilated garment.
FIG. 2 is a sectional view of the ventilated portion of the shell of the garment according to the first embodiment.
FIG. 3 is a schematic illustration representing a draining function of the first embodiment of the ventilated garment.
FIG. 4 is a sectional view of the ventilated portion of the shell of the garment according to a second embodiment.
FIG. 5 is a schematic illustration representing a draining function of the second embodiment of the ventilated garment.
FIG. 6 is an exploded perspective view of a third embodiment of the ventilated garment.
FIG. 7 is a sectional view of the ventilated portion of the shell of the garment according to a fourth embodiment.
FIG. 8 is a schematic illustration representing a draining function of the fourth embodiment of the ventilated garment.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated a ventilated garment generally indicated by reference numeral 10 . The garment 10 may comprise a jacket, pants or a bib pant which are typically worn as active outerwear by snowmobile and motorcycle operators and ski, snowboard and outdoor enthusiasts for example. The garment is well suited to protecting the user from various precipitations including rain or snow while providing adequate ventilation.
Various embodiments are disclosed in the accompanying drawings and description below; however, the common features of the various embodiments will first be described.
The garment 10 generally comprises a shell 12 which is arranged to be worn about the body of the user and which defines the general shape of the garment. In the instance of a jacket, the shell 12 typically comprises a torso portion and arms for being worn about the corresponding torso and arms of the user. Alternatively, when the garment comprises pants, the shell typically comprises two leg portions for being worn about the legs of the user.
The shell 12 includes one or more ventilated portions formed therein in which each ventilated portion is defined by an auxiliary layer 14 comprising a panel of material having a peripheral edge 16 fastened about the periphery of the ventilated portion defined in the shell. The panels forming the ventilated portion of the shell and the auxiliary layer 14 are mounted parallel and alongside one another across the full height and width of the layers.
As shown in FIGS. 1 through 5 , the auxiliary layer 14 is mounted adjacent and alongside the inner surface 18 of the shell such that the auxiliary layer defines an innermost layer 20 while the ventilated portion of the shell defines an outermost layer 22 . A ventilated area is defined between the innermost layer 20 and the outermost layer 22 . The ventilated area is understood to comprise herein an area or opening that can facilitate air exchange into and out of the garment.
According to FIG. 6 , the auxiliary layer may alternatively be mounted to span along the outer surface 24 of the shell. In this instance the auxiliary layer comprises the outermost layer 22 while the ventilated portion of the shell defines the innermost layer, in which the innermost and outermost layers again define the ventilated area therebetween.
In each instance the outermost layer 22 locates an exterior opening 26 therein. The exterior opening comprises an elongate slot extending in a longitudinal direction in the surrounding panel forming the outermost layer. A pair of opposed longitudinally extending edges 28 of the slot are flexible so as to be moveable between an open position in which the edges are spaced apart from one another to define the opening therebetween which is substantially unobstructed and a closed position in which the opposed edges 28 are joined with one another to close the exterior opening 26 .
A suitable fastener 30 is mounted on the outermost layer for operating the exterior opening between the open and closed positions thereof. In the illustrated embodiment the fastener 30 comprises a zipper in which a first element of the zipper spans along one of the edges 28 while a second element of the zipper spans along the opposing edge 28 . The elements of the zipper are selectively coupled to one another so as to be operable between an open condition of the fastener in the open position of the exterior opening and a closed condition of the fastener in the closed position of the exterior opening.
A drain opening 32 is provided in the outermost layer which is defined by a grommet comprising a reinforced eyelet secured about a hole punched into the panel of the outermost layer in the illustrated embodiment. Alternatively, the punched opening may comprise a stitched eyelet about the opening. In either instance, the reinforcing about the opening maintains the drain opening 32 in a fully open position in communication with the ventilated space between the shell and the auxiliary layer. The auxiliary layer and the shell are joined by an overlapping seam about the full perimeter of the auxiliary layer such that the innermost and outermost layers are sealed relative to one another about the full perimeter of the ventilated space defined therebetween.
The drain opening 32 is located adjacent the bottom end of the peripheral seam of the auxiliary layer joined to the shell. The bottom end of the seam which spans the full width of the ventilated area defined by the auxiliary layer is arranged to be sloped downwardly from one upright side edge of the auxiliary layer to the opposing upright side edge of the auxiliary layer. The downward sloping bottom end of the seam connecting the auxiliary layer to the shell thus defines a lowermost portion of the ventilated area adjacent one side. The drain opening is located adjacent to the lowermost portion at one side of the auxiliary layer. Accordingly, the bottom end of the ventilated area defined by the lower peripheral edge of the auxiliary layer slopes downwardly towards the drain opening.
The innermost layer comprises a panel locating a plurality of ventilated apertures 34 therein which are formed in a repeating grid pattern spanning across the ventilated area. In the illustrated embodiment, each of the ventilating openings 34 are substantially identical in size and spaced apart by an even spacing near to the dimension of the openings; however, the size and spacing of the openings may vary in further embodiments. All of the openings are provided in rows shown to be offset to one edge of the auxiliary layer so as to occupy a minimal area of the overall auxiliary layer; however, in further embodiments, the openings may be centrally located in the auxiliary layer. In particular, the overall combined area of the openings is arranged to be much less than the total area of the panel such that the majority of the panel forming the innermost layer comprises a moisture proof material.
Each of the ventilating openings 34 comprises a punched hole formed in the panel of material forming the innermost layer such that the remainder of the panel surrounding each opening provides support to the opening to maintain the opening in a fully opened condition at all times.
A mesh layer 36 is supported between the innermost and outermost layers such that the single panel forming the mesh layers spans all of the plurality of ventilating openings and such that ventilation air must pass through the mesh layer 36 from the exterior opening to the ventilation openings. The mesh layer 36 is only secured about its peripheral edge to one of the innermost or outermost layers of the ventilated area.
The mesh layer 36 comprises a mesh material having a mesh opening size which is sufficiently small to block the passage of snowflakes therethrough. In some embodiments, a hydrophobic coating is provided on the mesh material or in other embodiments, the mesh material may be made of a hydrophobic yarn to further resist the penetration of water or snow through the mesh layer while also providing some resistance to moisture wicking through the mesh layer. In this manner, the mesh layer defines a moisture repelling membrane allow air passage therethrough. This membrane may comprise a variety of materials both woven and knit goods.
The vent openings are provided in the innermost layer such that the lower edge of the openings are arranged to remain spaced above the lowermost periphery of the auxiliary layer joined to the shell as well as being spaced above the lowermost portion of the mesh layer 36 noted above. Accordingly, when snow enters through the exterior opening and melts in contact with the mesh layer 36 , the snow is trapped by the mesh and drips downwardly to a lowermost portion of the mesh which is below the ventilation openings. The moisture is thus led downwardly by gravity to a trough formed between the innermost and outermost layers below the ventilation openings and the exterior opening having a sloped bottom edge directed towards the drain opening for external draining. In the meantime, ventilation air continues to pass through the mesh layer above the moisture trapped in the lowermost portion of the mesh layer so that the ventilation air can reach readily from the exterior opening to the ventilating openings for ventilating the wearer.
To provide a better seal at the fastening of the peripheral edge of the auxiliary layer to the shell, a sealing tape member 38 formed of sealing material overlaps the peripheral edge of the auxiliary layer about the full perimeter. The tape member 38 is arranged for sealing engagement with both the auxiliary layer and the shell with which it is joined by applying the tape with a seam sealing machine that uses heat and pressure to bond the tape to the fabric of the different layers. Moisture channelled through the trough formed between the innermost and outermost layers is thus prevented from penetrating the seam along the lowermost edge to ensure the moisture is channelled only to the drain opening at the lowermost portion of the ventilated area offset to one side thereof.
Turning now more particularly to the embodiment of FIGS. 1 through 3 , the ventilated portion of the shell in this instance comprises the outermost layer of the ventilated area by supporting the auxiliary layer to span the inner surface of the shell. Also in this instance, the mesh layer is shown to fully span across the ventilated area by spanning the full width and height of the auxiliary layer and by being joined about the peripheral edge thereof to the peripheral edge of the auxiliary layer about the full perimeter of the ventilated area. The mesh layer thus remains parallel to the innermost and outermost layers across the full width and height thereof. The drain opening in this instance communicates with the space enclosed between the outer side of the mesh layer and the outermost layer so that moisture is substantially contained on the outer side of the mesh layer in direct communication with the drain and exterior openings.
Also shown in the embodiment in the embodiment of FIGS. 1 through 3 , the ventilation openings are located in the innermost layer so as to be offset upwardly and spaced above the exterior opening such that there is no overlap between the ventilating openings and the exterior opening. The longitudinal direction of the exterior opening slot is nearer to horizontal than vertical in orientation with the top and bottom edges of the auxiliary layer joined to the shell being substantially parallel to the longitudinal direction of the exterior opening slot. The peripheral edges of the exterior opening are also sloped downwardly towards the drain opening.
Turning now to the embodiment of FIGS. 7 and 8 , the inner and outer layers of the ventilated portion are substantially identical to the embodiment of FIGS. 1 through 3 ; however, the mesh layer 36 in this instance comprises a composite mesh layer. The composite mesh comprises a composite of various types of fibrous material including hydrophobic material either as a coating or as hydrophobic yarns which are assembled into a thickness comprising a plurality of layers of the fibrous material woven or matted together. More particularly, the composite mesh layers comprises several different hydrophobic or non hydrophobic fiber fill, matting or other components that will yield a significantly increased resistance to moisture wicking through the composite mesh and or material layer. In a preferred arrangement, the composite mesh layer 36 comprises an inner layer 36 A and an outer layer 36 B, each comprising a woven layer of hydrophobic yarn or other material with a hydrophobic coating. The space between the inner layer 36 A and the outer layer 3613 are filled with an intermediate layer 36 C comprising hydrophobic fiber fill or fiber matting to provide increased resistance to moisture penetration for extreme applications while still allowing air to freely ventilate through the gusset system.
In yet further embodiments, this composite material may eliminate the innermost layer so that the ventilated area or ventilated portion of the garment is simply defined between the outer layer and the composite mesh layer.
Turning now to the embodiment of FIGS. 4 and 5 , the mesh layer in this instance is shown secured about its periphery to the peripheral edge about the exterior opening of the outermost layer. As shown in the accompanying figures, the mesh panel forming the mesh layer spans an area which is greater than the area of the exterior opening in the fully open position such that a portion of the mesh may hang below the lowermost peripheral edge of the exterior opening for forming a lower trough portion within which precipitation can collect. Rain or melting snow is thus channelled to the lowermost portion of the mesh layer which is spaced below the ventilating openings so that the moisture dripping through the lower trough portion of the mesh layer is then channelled by the trough defined by the innermost and outermost layers of the ventilated area towards the drain opening. In each of the embodiments of FIGS. 1 through 5 , the ventilating air can still readily pass through the ventilated area from the exterior opening upwardly to the ventilating openings thereabove.
Turning now to the embodiment of FIG. 6 , the auxiliary layer is instead shown mounted to span the outer surface of the shell such that the auxiliary layer in this instance defines the outermost layer of the ventilated area while the ventilated portion of the shell enclosed by the auxiliary layer forms the innermost layer. The mesh layer in this instance also spans the outer surface of the shell when mounted between the shell and the auxiliary layer as in the previous embodiments. Accordingly the exterior opening is located in the auxiliary layer and the ventilating openings are located in the shell.
In the embodiment of FIG. 6 the bottom edge remains sloped across the full width of the auxiliary layer from the exterior opening which is vertically oriented adjacent one side of the ventilated area and the drain opening at the opposing side adjacent the lowermost portion of the peripheral edge of the auxiliary layer. In this instance the ventilated openings are provided in vertical row in substantial alignment with the exterior opening so that the ventilating openings and exterior opening overlap one another for optimal direct ventilation therebetween through the intermediate mesh layer. The mesh layer in this instance is also secured only at the peripheral edge adjacent the peripheral edge of the auxiliary layer about the full perimeter thereof. Moisture remains trapped between the mesh layer and the outermost layer of the ventilated area for being channelled to the drain opening instead of reaching the ventilating openings. The ventilating openings are sufficiently small in size that the surrounding panel locating the ventilating openings therein substantially prevents contact between the mesh layer and inner clothing layers of the user to prevent moisture wicking from the mesh layer to the inner layers of clothing in use unlike any other prior art ventilated garments.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense. | A ventilated garment includes a shell layer worn by the user and an auxiliary layer attached to a portion of shell to define a ventilated portion of the garment. An exterior opening formed in the outermost layer of the garment includes a fastener controlling the open or closed state of the exterior opening. A drain opening is also formed in the outermost layer separate from the exterior opening adjacent the bottom of the ventilated portion. Ventilating openings are formed in the waterproof innermost layer. A mesh layer spans the ventilating portion between the ventilating openings and the exterior opening to trap snow/rain and drain the precipitation through the drain opening therebelow to the exterior of the garment. The mesh layer blocks passage of precipitation therethrough while allowing a ventilating flow of air therethrough. | 0 |
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an image heating apparatus for heating a toner image on a sheet of recording medium with the use of a nip. In particular, it relates to an image heating apparatus which has a pair of rotational heating members, a pair of circularly movable heating belts, and an air blowing device, and is structured so that both the rotational heating members and circularly movable belts can be separately controlled in temperature from each other, and also, so that the air blowing device is used for preventing the belts from excessively increasing in temperature.
Image heating apparatuses having a combination of a pair of rotational heating members and a pair of circularly movable belts, which form a nip for heating a toner image on a recording medium have been in use for quite some time. In the case of the image heating apparatuses structured as described above, it is desired that the belt temperature is kept below the temperature of the rotational heating member, in order to prevent the problem that recording medium is given an excessive amount of heat. One of the methods for keeping the belt temperature below the temperature of the rotational heating member is to provide an image heating apparatus with an air blowing device, which is positioned so that it faces the outward surface of the belt, in terms of the loop which the belt forms. With the image heating apparatus being provided with the air blowing device, it is possible to keep the belt temperature below the temperature of the rotational heating member, by blowing air at the belt, during an image forming operation (Japanese Laid-open Patent Application 2006-119430).
The belt temperature and rotational heating member temperature are desired to be adjusted according to the thickness of the recording medium. In other words, in a case where a substantial number of sheets of the recording medium, which are different in thickness, are successively conveyed through an image heating apparatus, the belt temperature and rotational heating member temperature have to be changed in temperature according to the recording medium thickness. For example, in a case where a sheet of thin paper is conveyed immediately following a sheet of thick paper, both the belt temperature and rotational heating member temperature have to be lowered.
Japanese Laid-open Patent Application 2006-119430 discloses a method which quickly reduces the temperature range of a rotational member by placing an air blowing device so that the air blowing device faces a belt. More specifically, this method transfers heat from the rotational heating member to the belt by blowing air at the belt with the use of an air blowing device while the rotational heating member and belt are kept in contact with each other. This method, however, increases the belt temperature while reducing the rotational heating member in temperature. Thus, it cannot quickly reduce both the temperature of the rotational heating member and the belt, and therefore, it is possible that the use of this method will increase the length of time it takes to change in temperature both the rotational heating member and belt.
SUMMARY OF THE INVENTION
Thus, the primary object of the present invention is to provide an image heating apparatus which is provided with an air blowing device facing the belt of the image heating apparatus to cool the belt, and is structured so that it can quickly reduce in temperature both its rotational heating member and belt.
According to an aspect of the present invention, there is provided an image heating apparatus comprising a heating rotatable member; a belt cooperating with said heating rotatable member to form a nip for heating an image on the recording material; a heating device for heating said heating rotatable member; a controller for controlling a temperature of said heating rotatable member at a first temperature when the recording material has a first thickness, and for controlling the temperature at a second temperature which is lower from the first temperature when the recording material has a second thickness which is smaller than the first thickness; an air feeding device for feeding air to said belt during an image heating operation; a moving mechanism for spacing said belt from said heating rotatable member; and an executing portion capable of executing an operation in a mode in which said air feeding device feeds the air into between said belt and said heating rotatable member while said belt is spaced from said heating rotatable member with said belt and said heating member being rotating, wherein when the recording material having the second thickness is fed following the recording material having the first thickness, said executing portion executes the operation in said mode after the recording material having the first thickness passes through the nip and before the recording material having the second thickness is fed into the nip.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing for illustrating the structure of a typical image forming apparatus to which the present invention is applicable.
FIG. 2 is a block diagram of the control system of the image forming apparatus.
FIG. 3 is a drawing for illustrating the structure of the fixing device.
FIG. 4 is a drawing for illustrating the structure of the belt cooling system in the first embodiment of the present invention.
FIG. 5 is a flowchart of the control sequence for the belt cooling system in the first embodiment.
FIG. 6 is a drawing for describing the difference in terms of cooling performance (changes in temperature of fixation belt and pressure belt) among the image heating device in the first embodiment, comparative image heating device, and conventional image heating device, which occurred as recording medium was switched from thick paper (cardboard) to thin paper (coated paper).
FIG. 7 is a drawing for describing the difference in terms of cooling performance (changes in temperature of fixation belt and pressure belt) among the image heating device in the first embodiment, comparative image heating device, and conventional image heating device, which occurred as thin paper was selected as recording medium while the image forming apparatus was kept on standby.
FIG. 8 is a drawing for describing the structure of the belt cooling system in the first embodiment.
FIG. 9 is a drawing for describing how the belt cooling system is changed in the cooling area by an airflow direction changing member.
FIG. 10 is a drawing for describing the cooling effect of the belt cooling system in the second embodiment of the present invention.
FIG. 11 is a drawing for describing the cooling mode of the fixing device having a fixation roller, instead of a combination of a rotational heating member and a heating belt.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the embodiments of the present invention are described in detail with reference to the appended drawings. The present invention is applicable to any image heating apparatus (device) as long as the apparatus (device) is structured so that the airflow generated by the air blowing device positioned on the pressure belt side can be made to cool both the rotational heating member and the pressure belt, or only the pressure belt, with the use of a mechanism for pivotally moving the belt, even if the apparatus is partially or entirely different in structure from the image heating apparatus in the following embodiments of the present invention.
The following embodiments of the present invention are described with reference to image heating apparatuses (device) which employ a combination of a heat applying belt (which hereafter will be referred to simply as a heat belt), and a pressure applying belt (which hereafter may be referred to simply as pressure belt). However, the present invention is also applicable to image heating apparatuses (devices) which employs a combination of a heat belt and a pressure applying roller (which hereafter may be referred to simply as a pressure roller), and image heating apparatuses (devices) which employ a heat roller and a pressure belt. Further, not only is the present invention applicable to image heating apparatuses (device) as a fixing device, but also is applicable to gloss altering apparatuses or the like which are independent from an image forming apparatus.
The image forming apparatuses in which the image heating apparatus (device) in accordance with the present invention is installable are not limited to those which employ an intermediary transfer belt. That is, the image heating apparatus (device) in accordance with the present invention is also installable in those which directly transfer a toner image onto a sheet of the recording medium, those which employ an intermediary transfer drum, those which employ a the recording medium conveying belt, or the like image forming apparatus. In the description of the image heating apparatuses (devices) in the following embodiments of the present invention, only the portions of the image forming apparatus, which relate to the primary sections of the apparatus, that is, the sections which relate to the formation and transfer of a toner image, are described. However, the present invention is also applicable to image forming apparatuses other than those in the following embodiments of the present invention. For example, it is also applicable to various printing machines, copying machines, facsimile machines, and the like, which are the combination of one of the image forming apparatuses in the following embodiments of the present invention, and additional devices, equipments, a case (container).
<Image Forming Apparatus>
FIG. 1 is a drawing for illustrating the structure of a typical image forming apparatus to which the present invention is applicable. FIG. 2 is a block diagram of the control system of the image forming apparatus. Referring to FIG. 1 , the image forming apparatus 100 has image formation stations Pa, Pb, Pc and Pd which form yellow, magenta, cyan and black monochromatic toner images, respectively, which are aligned in tandem in the recording medium conveyance direction, and an intermediary transferring member. That is, it is a full-color printer of the tandem type, and also, of the intermediary transfer type.
In the image formation station Pa, a yellow toner image is formed on a photosensitive drum 3 a , and is transferred onto an intermediary transfer belt 130 . In the image formation station Pb, a magenta toner image is formed on a photosensitive drum 3 b , and is transferred onto the intermediary transfer belt 130 . In the image formation station Pc, a cyan toner image is formed on a photosensitive drum 3 c , and is transferred onto an intermediary transfer belt 130 . In the image formation station Pd, a black toner image is formed on a photosensitive drum 3 d , and is transferred onto the intermediary transfer belt 130 .
A secondary transfer roller 11 forms a secondary transfer station T 2 , by being placed in contact with the intermediary transfer belt 130 which is backed up by a belt backing roller 14 from within the loop which the belt 130 forms. As a sheet P of the recording medium is pulled out of a recording medium cassette 10 ( 10 a or 10 b ) while being separated from the rest of the sheets P in the cassette 10 , it is sent to a pair of registration rollers 12 , which conveys the sheet P to the secondary transfer station T 2 with such a timing that the sheet P arrives at the secondary transfer station T 2 at the same time as the toner image(s) on the intermediary transfer belt 130 . In the secondary transfer station T 2 , the toner images and the sheet P are conveyed in layers while remaining pinched by the secondary transfer roller 11 and intermediary transfer belt 130 . While the combination of the toner images, the sheet P is conveyed through the secondary transfer station T 2 , and a preset positive DC voltage is applied to the secondary transfer roller 11 . Thus, a full-color toner image (made up of four monochromatic toner images different in color) is transferred (secondary transfer) from the intermediary transfer belt 130 onto the sheet P. A belt cleaning device 19 recovers the transfer residual toner, that is, the toner which failed to be transferred onto the sheet P, and therefore, remains on the intermediary transfer belt 130 .
After the transfer of the four monochromatic toner images, different in color, onto the sheet P of the recording medium, the sheet P is separated from the intermediary transfer belt 130 with the utilization of the curvature of the portion of the intermediary transfer belt 130 , which corresponds in position to the belt backing roller 14 . Then, the sheet P is sent into a fixing device 9 , which melts the toner by applying heat to the toner while applying pressure to the toner. Thus, the toner images are fixed to the sheet P. Thereafter, the sheet P is discharged from the main assembly of the image forming apparatus 100 by way of a pair of discharge rollers 73 .
The image formation stations Pa, Pb, Pc and Pd are practically the same in structure, although they are different in the color (yellow, magenta, cyan and black) of the toner they use. Hereafter, therefore, only the image formation station Pa is described. The description of the image formation stations Pb, Pc and Pd is the same as that of the image formation station Pa except for the suffixes b, c and d which indicate to which image formation station P each component belongs.
The image formation station Pa comprises a photosensitive drum 3 a , a charge roller 2 a , an exposing device 5 a , a developing device la, a transfer roller 24 a , and a drum cleaning device 4 a . The charge roller 2 a , the exposing device 5 a , the developing device 1 a , the transfer roller 24 a , and the drum cleaning device 4 a are in the adjacencies of the peripheral surface of the photosensitive drum 3 a . The photosensitive drum 3 a has a negatively chargeable photosensitive layer. It rotates in the direction indicated by an arrow mark at a process speed of 200 mm/sec.
The charge roller 2 a uniformly and negatively charges the peripheral surface of the photosensitive drum 3 a to a preset level VD (which hereafter may be referred to as “dark potential level”). The exposing device 5 a writes an electrostatic image of the image to be formed. More concretely, it scans the uniformly charged area of the peripheral surface of the photosensitive drum 3 a with a beam of laser light it outputs while deflecting the beam with its rotational mirror. Thus, the exposed points of the uniformly charged area of the photosensitive drum 3 a decrease in potential level to a level VL (which hereafter may be referred to as “light potential level”). Consequently, an electrostatic image of the image to be formed is effected on the peripheral surface of the photosensitive drum 3 a . The developing device 1 a develops the electrostatic image on the photosensitive drum 3 a , into a visible image, that is, an image formed of toner, with the use of two-component developer made up of toner and carrier.
The transfer roller 24 a forms, between the photosensitive drum 3 a and intermediary transfer belt 130 , a transfer station, in which the toner image is transferred onto the intermediary transfer belt 130 . To the transfer roller 24 a , a preset transfer voltage, which is opposite in polarity from the polarity to which toner is charged is applied. As the portion of the peripheral surface of the photosensitive drum 3 a , on which toner is present, moves through the transfer station, the toner (which makes up visible image) is transferred onto the intermediary transfer belt 130 . The drum cleaning device 4 a recovers the transfer residual toner, that is, the toner which failed to be transferred from the photosensitive drum 3 a , and therefore, remains on the photosensitive drum 3 a.
The image forming apparatus 100 can continuously output prints by sequentially repeating the process of feeding a sheet of recording paper into the main assembly of the image forming apparatus 100 , the process of forming an unfixed toner image, the process of fixing an unfixed toner image, and the process of discharging the sheet of the recording medium. It can output 80 full-color prints per minute when the recording medium is a sheet of ordinary paper, which is A4 in size.
Referring to FIG. 2 , the image forming apparatus 100 has: a control section 141 made up of a microcomputer; and a control panel which functions as an interface for a user to access the image forming apparatus 100 . The control section 141 oversees the image forming operation of the image forming apparatus 100 while observing and controlling the operation of each of the various sections of the image forming apparatus 100 . The control panel 142 is the section through which basic information of a print job (information, such as basis weight of the recording medium, the density of the image to be formed, the number of prints to be made, etc.), and/or the detailed setting for a so-called “serial job”, that is, a printing job made up of a serial combination of smaller jobs which are different in the recording-medium type.
<Fixing Device>
FIGS. 3( a ) and 3 ( b ) are drawings illustrating the structure of the fixing device 9 . FIG. 3( a ) shows the state of the fixing device 9 , in which the pressure belt is in contact with the heat belt (fixation belt). FIG. 3( b ) shows the state of the fixing device, in which a space is present between the heat belt (fixation belt) and pressure belt.
Referring to FIG. 3( a ), the fixing device 9 is made up of a fixation belt 51 , and a pressure belt 52 , which is pressed upon the fixation belt 51 to form a heating nip N. The fixation belt 51 is controlled in temperature so that its temperature remains above the melting point of the toner. A sheet P of the recording medium, on which toner image(s) is present, is conveyed through the heating nip N while remaining pinched by the fixation belt 51 and the pressure belt 52 . Consequently, the toner image(s) on the sheet P is fixed to the sheet P by the heat and pressure applied to the sheet P and the toner image(s) thereon, by the fixing device 9 . The pressure belt 52 , which is an example of an endless belt, can form, between itself and fixation belt 51 , the heating hip N for heating the sheet P and the toner image(s) thereon. The fixation belt 51 is positioned above the pressure belt 52 , and its temperature is kept at a higher target level than that for the pressure belt 52 .
The fixation belt 51 and pressure belt 52 of the fixing device 9 form the heating nip N, which is rectangular in shape, and the widthwise direction of which is parallel to the direction in which a sheet P of the recording medium is conveyed. A combination of the fixation belt (heating belt) driving roller 101 , and a stay 105 , which is in the form of a pad, and a combination of a pressure roller 102 and a pressure pad 106 , sandwich the portion of the fixation belt 51 , and the portion of the pressure belt 52 , which are within the heating nip N. A sheet P of the recording medium is conveyed through the fixing device 9 in the right-to-left direction, while being subjected to heat and pressure, in the heating nip N. Consequently, the toner image(s) on the sheet P is fixed to the surface of the sheet P.
The fixation belt 51 is supported by the fixation belt driving roller 101 , and a tension roller 103 which functions as a roller for providing the fixation belt 51 with a preset amount of tension, by being wrapped around the two rollers 101 and 103 . The substrate of the fixation belt 51 is an endless metallic belt formed of nickel, and is 50 μm in thickness, 380 mm in width, and 160 mm in length. The substrate is coated with a layer of silicon rubber, which is 400 μm in thickness. The silicon rubber layer is covered with a surface layer, which is made of PFA tube and is 40 μm in thickness.
The fixation belt driving roller 101 is a hollow roller which is made of a piece of stainless steel pipe. It is 20 mm in external diameter. The tension roller 103 also is a hollow roller which is made of a piece of stainless steel pipe. It is 20 mm in external diameter, and 18 mm in internal diameter. Its lengthwise end portions are under the pressure from a pair of unshown tension springs, providing thereby the fixation belt 51 with a preset amount of tension.
There is a pressure pad 105 on the inward side of the loop which the fixation belt 51 forms. The pressure pad 105 is formed of stainless steel, and is positioned on the entrance side of the heating nip N so that it opposes the pressure pad 106 . The pressure pad 105 doubles as a heat storing member for preventing the heating nip N from reducing in temperature when a sheet P of the recording medium is conveyed through the heating nip N.
The pressure belt 52 is supported by the pressure roller 102 , and a tension roller 104 which is given the function of providing the pressure belt 52 with a preset amount of tension, by being wrapped around the two rollers 102 and 104 . The substrate of the pressure belt 52 is an endless metallic belt formed of nickel, and is 50 μm in thickness, 380 mm in width, and 172 mm in length. The substrate is coated with a layer of silicon rubber, which is 350 μm in thickness. The silicon rubber layer is covered with a surface layer, which is made of PFA tube and is 40 μm in thickness.
The pressure roller 102 is a hollow roller which is made of a piece of stainless steel pipe. It is 20 mm in external diameter. The tension roller 104 also is a hollow roller which is made of a piece of stainless steel pipe. It is 20 mm in external diameter, and 18 mm in internal diameter. Its lengthwise end portions are under the pressure from a pair of unshown tension springs, providing thereby the pressure belt 52 with a preset amount of tension. There is the pressure pad 106 on the inward side of the loop which the pressure belt 52 forms. The pressure pad 106 is formed of silicone rubber, and is on the entrance side of the heating nip N. Further, the pressure pad 106 is kept pressed upon the inward surface of the pressure belt 52 with the application of a total pressure of 400 N.
There is a first heating element 201 in the hollow of the fixation belt driving roller 101 . The rated power of the first heating element 201 is 1,000 W. Further, there is a second heating element 202 in the hollow of the pressure roller 102 , the rated power of the second heating element is also 1,000 W. The fixation belt driving roller 101 and pressure roller 102 are in connection with each other through a pair of gears attached, one for one, to one of the lengthwise ends of the roller 101 and the same lengthwise end of the roller 102 . Thus, the two rollers 101 and 102 rotate with roughly the same peripheral velocity by being driving by an external force. Therefore, the fixation belt 51 and the pressure belt 52 circularly move with roughly the same speed whether they are kept in contact with each other, or kept separated from each other.
<Pressure Belt Pivoting Mechanism>
A pressure belt pivoting mechanism 207 can place the pressure belt 52 in contact with the fixation belt 51 or separate the pressure belt 52 from the fixation belt 51 . The mechanism 207 is such a mechanism that can pivotally move the tension roller 104 (which supports pressure belt 52 , on the recording medium entrance side of heating nip N) about an axis 111 , which is on the recording medium exit side of the heating nip N.
The pressure belt 52 , the pressure roller 102 , the pressure pad 106 , and the tension roller 104 are attached to a plate 113 , which is pivotally movable about the axis 111 . Thus, they make up a pressure application unit which can be pivotally moved, along with the plate 113 , about the axis 111 . Further, the fixing device 9 is provided with a pair of pressure application arms 112 and a pair of pivotally movable pressure application plates 113 , the positions of which correspond to the lengthwise ends, one for one, of the pressure roller 102 , are independently and pivotally movable about the axis 111 . The pressure roller 102 and the pressure pad 106 are supported by a pressure application plate 114 , and are kept pressed upward by a pair of compression springs 115 .
The fixing device 9 is also provided with a pressure application cam 120 , which is in contact with the bottom surface of the pivotally movable pressure application plate 113 . Thus, as the pressure application cam 120 rotates, the plate 113 is moved upward or downward, causing the pressure belt 52 to be pressed upon the fixation belt 51 or to be separated from the belt 51 . The pressure application cam 120 is driven by the pressure belt pivoting mechanism 207 , thereby making the pressure belt 52 (supported by the pressure pad 106 , and the tension roller 104 ) pivot upward or downward about the axis 111 .
The control section 141 can press the pressure belt 52 upon the fixation belt 51 , or separate the pressure belt 52 from the fixation belt 51 . The amount of distance provided between the pressure belt 52 and fixation belt 51 is optional. The total amount of load applied between the fixation belt 51 and pressure belt 52 as the pressure belt 52 is pressed upon the fixation belt 51 is roughly 800 N (80 kgf). As the pressure belt 52 is pressed upon the fixation belt 51 , the heating nip N is formed, which is rectangular, and the dimension of which in the recording medium conveyance direction is roughly 15 mm. The conventional objectives of the pressure belt pivoting mechanism 207 are to make it easier for a user to deal with paper jam or the like problems, to extend the fixation belt 51 in service life, to prevent the pressure belt 52 from increasing in temperature while no sheet of paper is conveyed through the heating nip N, or the like.
However, if the temperature of the pressure belt 52 is excessively high when the pressure belt 52 is pressed upon the fixation belt 51 , the moisture in a sheet of coated paper evaporates into steam, and the steam breaks through the coated surface layer of the sheet and erupts from the sheet P. As the steam breaks through the coated surface layer, it disturbs the toner image(s) on the surface of the sheet P, causing a phenomenon called “blistering”. Further, if the temperature of the pressure belt 52 is excessively high, the moisture in a sheet P of the recording medium evaporates into steam, and the steam reduces the amount of the friction between the pressure belt 52 and the bottom surface of the sheet P. The reduction in the amount of the friction between the pressure belt 52 and the bottom surface of the sheet P makes the pressure belt 52 and sheet P slip relative to each other, making it possible for the sheet P to be improperly conveyed. Further, if the steam attributable to the evaporation of the moisture in the sheet P settles between the fixation belt 51 and the image bearing surface of the sheet P, it is likely for the fixation belt 51 to float above the image bearing surface of the sheet P, and therefore, it is possible for the image forming apparatus 100 to output images which are nonuniform in gloss.
Therefore, the image forming apparatus 100 in this embodiment is controlled so that the temperature of the pressure belt 52 is kept substantially lower than that of the fixation belt 51 . Further, while no sheet of the recording medium is conveyed, the pressure belt 52 is kept separated from the fixation belt 51 by the pressure belt pivoting mechanism 207 in order to prevent the fixation belt 51 from being reduced in temperature. Therefore, it is ensured that the fixing device 9 can satisfactorily fix the toner image(s) on the sheet P of the recording medium to the sheet P while minimizing the amount by which heat is applied to the sheet P.
<Temperature Control of Fixing Device>
Next, referring to FIG. 2 as well as FIG. 3 , a temperature control section 200 adjusts the fixation belt 51 in surface temperature, by controlling the amount of electric power supplied to the first heating element 201 (heating device), based on the temperature of the fixation belt 51 detected by first temperature detection element 205 , which is on the downstream side of the heating nip N and is in contact with the center of the fixation belt 51 in terms of the widthwise direction of the belt 51 . Further, the temperature control section 200 adjusts the pressure belt 52 in surface temperature by controlling the amount of electric power supplied to the second heating element 202 (heating device), based on the temperature of the pressure belt 52 detected by the second temperature detection element 206 , which is on the downstream side of the heating nip N and is in contact with the center of the pressure belt 52 in terms of the widthwise direction of the belt 51 , and also, controls the air blowing fan 203 . The first and second heating elements 201 and 202 in this embodiment are halogen lamps. However, they may be replaced with heat generating resistors, induction heating elements, or the like.
As a print job is started, the control section 141 selects a target temperature level for the temperature adjustment of the fixing device 9 , based on the information of a sheet P of the recording medium inputted through the control panel 142 , and makes the temperature control section 200 control the fixation belt 51 and the pressure belt 52 in temperature, based on the selected target temperature level. Table 1 is a target temperature table for the temperature control of the fixing device 9 . It is to be used when the image on a sheet P of the recording medium is heated for fixation while the fixation belt 51 and pressure belt 52 are kept in contact with each other. That is, during an image forming operation, the heating device 9 and air blowing fan 203 are controlled so that the temperature of the fixation belt 51 and that of the pressure belt 52 remain at their target temperature levels, respectively.
TABLE 1
Job Start
Target Temp.
Discriminating Temp.
Basis Wt.
Fixing
Pressing
Fixing
Materials
(g/m{circumflex over ( )}2)
Belt
Belt
Belt
Pressing Belt
Thick 2
181-256
190° C.
100° C.
190° C.
100° C.-120° C.
Thick 1
106-180
185° C.
100° C.
185° C.
100° C.-120° C.
Plain 2
91-105
180° C.
100° C.
180° C.
100° C.-120° C.
Plain 1
64-90
175° C.
100° C.
175° C.
100° C.-110° C.
Thin
52-63
165° C.
100° C.
165° C.
100° C.-110° C.
Coated
106-180
170° C.
100° C.
170° C.
100° C.-110° C.
Referring to Table 1, the control section 141 controls in temperature the fixation belt 51 and the pressure belt 52 by selecting a proper target level for each belt, from among the several levels, according to the recording medium type (basis weight, surface properties, etc.). For paper which is not coated, for example, ordinary printing paper or the like, the target temperature is set to a level which can satisfy both the conveyablility of the recording medium (wrinkle prevention, ease of separation, etc.) and image quality (fixation, toner-offset, surface gloss, etc.). In other words, the greater in basis weigh the recording medium, the higher the level to which the target temperature is set. In comparison, for coated paper, that is, paper, the surface layer of which is formed of resin, the target temperature is set to a level which is specific for satisfying not only the basis requirements (conveyability, image quality), but also, for the prevention of the occurrence of such problems as the recording medium conveyance error and formation of defective images that are peculiar to coated paper. That is, in order to prevent the amount of heat applied to the recording medium to heat the image on the recording medium, from becoming excessive, the target temperature for the pressure belt 52 is set lower than that for the fixation belt 51 as shown in Table 1 . In order to keep the temperature of the pressure belt 52 at one of its target levels, the control section 141 controls the air blowing fan 203 according to the selected temperature level for the pressure belt 52 . That is, as the temperature of the pressure belt 52 becomes higher than the selected level, the control section 141 operates the air blowing fan 203 , and as the temperature of the pressure belt 52 becomes lower than the selected level, the control section 141 stops the air blowing fan 203 .
From the standpoint of both the conveyability of the recording medium, and image quality, the target temperature for the fixation belt 51 and the job start temperature are set so that the greater in basis weight a sheet P of the recording medium, the higher the level to which the target temperature is set.
Basically, the target temperature for the pressure belt 52 is set to 100° C. regardless of the recording medium type. However, as a substantial number of sheets of the recording medium are continuously conveyed through the fixing device 9 , the pressure belt 52 increases in temperature, because the fixation belt 51 comes into contact with the pressure belt 52 during the sheet intervals. Therefore, a print job interruption temperature is provided for the pressure belt 52 . If the temperature of the pressure belt 52 reaches the print job interruption temperature, the ongoing image forming operation is interrupted to reduce the pressure belt 52 in temperature, and the image forming apparatus 100 is idled until the pressure belt temperature falls below the print job interruption level.
Referring to Table 1, in an image forming operation in which the recording medium is an ordinary paper 1 (which is small in basis weight) or thin paper, the heat of the pressure belt 52 is likely to be transmitted to the toner layer through a sheet P of the recording medium, and excessively melt the toner layer, because of the thinness of the recording medium. As the toner layer excessively melts, the melted toner is likely to flow along the microscopic hills and valleys of the surface of the recording medium, making thereby the toner image nonuniform in density as the toner image becomes fixed. Therefore, for ordinary paper 1 or thin paper the print job interruption temperature is set to 110° C. Further, as the toner layer on the paper whose surface has numerous microscopic hills and valleys is excessively melted, the toner which is on the microscopic hill portions of the paper flows down to microscopic valley portions of the paper, because the excessively melted toner is very low in viscosity. Consequently, the toner image becomes conspicuously nonuniform in density and gloss, compared to a toner image, the portions of which on the microscopic hills of the sheet of the recording medium are the same in the amount of the toner as the portions of which in the microscopic valleys of the sheet of the recording medium. Therefore, for coated paper, the print interruption temperature for the pressure belt 52 is set to 110° C., in order to prevent the occurrence of the above described blistering. For recording media other than coated paper, the print interruption temperature for the pressure belt 52 is set to 120° C. in order to prioritize the conveyability of the recording medium (wrinkling prevention, ease of separation).
TABLE 2
Target temperature
Fixing roller
Pressing roller
180° C.
100° C.
Referring to Table 2, the default setting for the standby target temperature is 180° C. for the fixation belt 51 , and 100° C. for the pressure belt 52 , in order to make it possible to immediately (without any waiting period) start a pending image forming operation when ordinary paper 2 , which is more frequently used than the other type of recording medium, is used as the recording medium. Incidentally, the default setting for the standby target temperature may be named as “target temperature level for default paper”, and displayed as such on the display of the control panel 142 .
The fixing device 9 is provided with multiple levels of target temperature. Therefore, each time it is switched in the target temperature, a waiting period occurs. The print start temperature is affected by the type and basis weight of the recording medium. Thus, as the recording medium is switched in type and/or basis weight, the fixation belt 51 and pressure belt 52 have to be heated or cooled so that their temperatures settle at their print start temperatures.
In particular, in a case where the fixing device 9 is large in thermal capacity, it takes a substantial length of time for the fixing device 9 to be cooled. Thus, when it becomes necessary for the device 9 to be cooled, a substantial length of waiting time is required after the switching of the target temperature. An image heating device for a high-speed image forming apparatus is structured to be large in thermal capacity in order to be prevented from decreasing in temperature while a substantial number of sheets of the recording medium are continuously conveyed through the fixing device. Therefore, if the new target temperature level is lower than the immediately preceding target temperature level, it takes more time for the fixing device to reach the new target temperature level, affecting thereby the image forming apparatus 100 in overall productivity, than if the new target temperature level is higher than the immediately preceding target temperature level.
For example, in a case where the fixing device 9 is switched in target temperature to the level for thin paper from the standby period level shown in Table 2, it takes a substantial length of time for the temperatures of the fixation belt 51 and the pressure belt 52 to settle at their new target temperature levels. In other words, a substantial length of downtime occurs, and therefore, the image forming apparatus 100 decreases in productivity. Further, in the case of a “serial job”, that is, a job in which an image formation sequence in which a substantial number of sheets of thin paper are continuously conveyed, and an image formation sequence in which a substantial number of sheets of thick paper are continuously conveyed are alternately carried out, the downtime for cooling occurs each time the image forming apparatus 100 is switched in image formation sequence (the recording medium is switched from thick paper to thin paper). Therefore, in the case of a “serial job”, the image forming apparatus 100 is significantly lower in productivity than in a case of a job in which only the ordinary paper 2 is used as the recording medium. The frequent occurrence of the downtime is not desirable from the standpoint of usability.
One of the conventional methods for cooling the fixation belt 51 is to press the pressure belt 52 upon the fixation belt 51 .
However, in a case where an image formation sequence in which a substantially number of sheets of thick paper are continuously conveyed is replaced with an image formation sequence in which a substantial number of sheets of thin paper are continuously conveyed, in a “serial job”, for example, it is necessary to cool both the fixation belt 51 and pressure belt 52 as shown in Table 2. When the recording medium is thick paper 2 , the target temperature for the fixation belt 51 is 190° C. (first level), whereas when the recording medium is thin paper 1 , it is 165° C. (second level, which is lower than first level). In a situation such as the above-described one, the conventional method is effective as the method for quickly lowering the temperature of the fixation belt 51 . However, the conventional method increases the temperature of the pressure belt 52 as well. Thus, the overall length of time required to reduce in temperature both the fixation belt 51 and pressure belt 52 to their target levels is rather long. In recent years, from the standpoint of reducing energy consumption, it has been desired to reduce the amount of toner consumption by an image forming apparatus as much as possible while ensuring that image quality is maintained at a conventional level or higher. One of the methods for maintaining image quality while reducing the amount of toner consumption compared to the conventional method is to increase toner in pigment ratio. Because of the recent trend in which it is desired to reduce an image forming apparatus in toner consumption, it has become very important to control the fixation belt 51 and pressure belt 52 in temperature, in particular, to prevent the pressure belt 52 from excessively increasing in temperature. Further, from the standpoint of preventing the problem attributable to the excessive melting of the toner layer, it has become very important to prevent the pressure belt 52 from excessively increasing in temperature, in order to prevent the toner layer from being supplied with an excessive amount of heat from the portions of the pressure belt 52 , which are outside the recording medium path in terms of the lengthwise direction of the belt 52 .
In this embodiment, therefore, air is blown upon the pressure belt 52 during an image forming operation. Further, while the fixation belt 51 and pressure belt 52 are changed in temperature, air is blown into the space between the fixation belt 51 and pressure belt 52 . That is, the fixing device 9 is provided with an air blowing device for cooling the belts 51 and 52 . Therefore, both the rotational heating members and belts can be quickly reduced in temperature immediately after the switching of the target temperature for the belts 51 and 52 .
<Embodiment 1>
FIG. 4 is a drawing for illustrating the structure of the belt cooling system in the first embodiment of the present invention. FIG. 5 is a flowchart of the operational sequence for controlling the fixation belt 51 and pressure belt 52 in the first embodiment. FIG. 6 is a drawing for describing how the fixation belt 51 and pressure belt 52 are cooled after the recording medium is switched from thick paper to thin paper.
Referring to FIG. 4 , the air blowing fan 203 , which is an example of an air blowing device, is on the pressure belt side of the recording medium passage of the heating nip N. In terms of the recording medium conveyance direction, the air blowing device is on the upstream side of the heating nip N as shown in FIG. 4 . Moreover, the position of the air blowing device corresponds to the upstream side of the pressure belt in terms of the recording medium conveyance direction. The air blowing fan 203 can be made to cool, with air, the portion of the pressure belt 52 , which is facing opposite from the fixation belt 51 , or the portion of the pressure belt 52 , which is facing the fixation belt 51 , as the tension roller 104 is pivotally moved about the axis 111 . More concretely, as the pressure belt pivoting mechanism 207 separates the pressure belt 52 from the fixation belt 51 , the airflow generated by the air blowing fan 203 moves along the upstream portion of the top portion of the pressure belt 52 , which is on the upstream side of the heating nip N, and reaches fixation belt 51 . That is, the air blowing device sends air through the space between the fixation belt 51 and pressure belt 52 . On the other hand, as the pressure belt pivoting mechanism 207 places the pressure belt 52 in contact with the fixation belt 51 , the airflow which is generated by the air blowing fan 203 and would have reached the fixation belt 51 , is blocked by the pressure belt 52 . Thus, the air blowing fan 203 sends air only to the pressure belt 52 . Further, the fixing device 9 in this embodiment is provided with a member 210 for changing the direction in which the airflow generated by the air blowing fan 203 moves. That is, the member 210 can direct the airflow generated by the air blowing fan 203 toward the pressure belt 52 , or the space between the fixation belt 51 and pressure belt 52 .
As described above, the fixing device 9 in this embodiment is structured so that (a) not only can the pressure belt 52 be changed in attitude by the pressure belt pivoting mechanism 207 , but also, (b) the airflow generated by the air blowing fan 203 can be changed in direction by an airflow direction changing member 210 , that is, a member for changing the direction of the airflow.
The control section 141 , which is an example of a controlling means, functions as the section for operating the fixing device 9 in a cooling mode (first cooling mode) in which both the fixation belt 51 and pressure belt 52 are cooled. Further, the control section 141 functions also as the section for operating the fixing device 9 in a cooling mode (second cooling mode) in which only the pressure belt 52 is cooled. In this embodiment, as the target temperature for the fixation belt 51 is lowered, the control section 141 operates the fixing device 9 in the first cooling mode first, and then, operates the fixing device 9 in the second cooling mode.
Referring to FIG. 4( a ), in the first cooling mode, the pressure belt 52 is separated from the fixation belt 51 in order to make the airflow generated by the air blowing fan 203 to be guided to the fixation belt 51 by the upwardly facing portion of the pressure belt 52 , so that both the fixation belt 51 and pressure belt 52 are cooled. That is, in the first cooling mode, air is blown through the space between the fixation belt 51 and pressure belt 52 by the air blowing fan 203 . More concretely, the airflow generated by the air blowing fan 203 flows along the portion of the pressure belt 52 , which faces toward the fixation belt 51 , and moves through the space between the fixation belt 51 and pressure belt 52 .
Next, referring to FIG. 4( b ), in the second cooling mode, the distance by which the pressure belt 52 is separated from the fixation belt 51 is made smaller than that in the first cooling mode, so that the pressure belt 52 becomes the primary object to be cooled by the airflow generated by the air blowing fan 203 .
In the first embodiment, the object to which air is sent by the air blowing fan 203 is changed by changing the position of the tension roller 104 (attitude of pressure belt 52 ) with the use of the pressure belt pivoting mechanism 207 . That is, as the mechanism 207 separates the pressure belt 52 from the fixation belt 51 , it becomes possible for the air blowing fan 203 to sent air to the space between the fixation belt 51 and pressure belt 52 .
Thereafter, the control section 141 controls the movement of the airflow direction changing member 210 . That is, the control section 141 controls the airflow direction changing member 210 in such a manner that as the pressure belt 52 is separated from the fixation belt 51 , the airflow is directed toward the space between the fixation belt 51 and pressure belt 52 by the member 210 .
Next, referring to FIG. 5 along with FIG. 4 , if the target temperature for the pressure belt 52 after the switching of the recording medium is different from the actually measured current temperature of the pressure belt 52 (S 1 ), the control section 141 decides whether it is necessary to cool the pressure belt 52 or not (S 2 ). If it is unnecessary to cool the pressure belt 52 (No in S 2 ), the control section 141 does not activate the air blowing fan 203 (S 9 ), and controls the temperature control section 200 to activate the first heating element 201 and second heating element 202 (S 3 ). Then, as soon as the temperature of the fixation belt 51 and the temperature of the pressure belt 52 reach their target level, the control section 141 makes the image forming apparatus 100 start a printing job (S 4 ). This is a temperature increasing process that does not require cooling. Therefore, it takes a relatively short length of time to start the job.
If it is necessary to cool the pressure belt 52 (Yes in S 2 ), the control section 141 decides whether it is necessary to cool the fixation belt 51 (S 5 ).
If it is necessary to cool the fixation belt 51 (Yes in S 5 ), the control section 141 pivotally moves the tension roller 104 of the pressure belt 52 about the axis 111 to change the pressure belt 52 in attitude so that a space large enough for the airflow generated by the air blowing fan 203 to flow through is created between the fixation belt 51 and pressure belt 52 as shown in FIG. 4( a ) (S 6 ). Then, the control section 141 turns on the air blowing fan 203 (S 8 ) to simultaneously cool both the fixation belt 51 and pressure belt 52 . That is, the pressure belt 52 is kept separated from the fixation belt 51 (presence of large distance between two belts 51 and 52 ), and the airflow generated by the air blowing fan 203 moves between the fixation belt 51 and pressure belt 52 .
As the fixation belt 51 is cooled enough, that is, it becomes unnecessary to cool the fixation belt 51 (No in S 5 ), the control section 141 pivots the pressure belt 52 about the axis 111 toward the fixation belt 51 , and stops the pressure belt 52 right before the pressure belt 52 comes into contact with the fixation belt 51 , as shown in FIG. 4( b ) so that the pressure belt 52 is prevented from being directly heated by the fixation belt 51 (S 7 ). Then, the control section 141 cools only the pressure belt 52 by the air blowing fan 203 while keeping the pressure belt 52 separated from the fixation belt 51 by such a distance (small distance) that can prevent the pressure belt 52 from being heated by the fixation belt 51 (S 8 ).
Then, as the fixation belt 51 is cooled enough, that is, as it becomes unnecessary to cool the pressure belt 52 (No in S 2 ), the control section 141 stops sending air to the pressure belt 52 (S 9 ), and goes back to the normal temperature control process (S 3 ). Then, it makes the image forming apparatus 100 start the print job (S 4 ).
The first embodiment is described with reference to a “serial job”, in which a substantial number of prints are continuously outputted with the use of sheets of thick paper, and then, the recording medium is switched to coated paper. Referring to Table 1, the target temperatures for thick paper 2 were 190° C./118° C. (fixation belt/pressure belt). However, as the sheets of thick paper were continuously conveyed through the fixing device 9 , the pressure belt 52 increased in temperature.
In the case of the fixing device in the first embodiment, the temperatures of the fixation belt 51 and pressure belt 52 right after 200 sheets of thick paper 2 were continuously conveyed through the fixing device 9 were 190° C/118° C. (fixation belt/pressure belt). Referring to Table 1, when the recording medium is coated paper, the target temperatures for the fixation belt 51 and pressure belt 52 are 170° C/110° C. (fixation belt/pressure belt). Therefore, both the fixation belt 51 and pressure belt 52 had to be cooled before it became possible for coated paper to be used as the recording medium.
In the experiment carried out to test the above described fixing apparatus in the first embodiment, a substantial number of sheets of thick paper 2 were continuously conveyed through the fixing device 9 up to a point in time of 0 minute 0 second as indicated by round black dots (bold line) in FIG. 6 . Then, both the fixation belt 51 and pressure belt 52 began to be cooled at 0 minute 0 second, with the presence of a space between the fixation belt 51 and pressure belt 52 as shown in FIG. 4( a ). The temperature of the fixation belt 51 reduced to a target level of 170° C. with the elapse of 21 seconds. Then, the pressure belt 52 was pivotally moved back toward the fixation belt 51 until the distance between the fixation belt 51 and pressure belt 52 became the preset minimum, as shown in FIG. 4( b ), and the cooling of the pressure belt 52 was immediately started. At this point in time, however, the temperature of the pressure belt 52 had already reduced to 110° C. Therefore, the image forming operation which uses sheets of coated paper was started at the same time as the temperature of the fixation belt 51 came down to 170° C.
In this experiment, the conventional method for cooling the fixation belt 51 and pressure belt 52 was also studied. That is, the temperature of the fixation belt 51 was reduced to 170° C. while the pressure belt 52 was kept pressed upon the fixation belt 51 . Then, the pressure belt 52 was separated from the fixation belt 51 , and the temperature of the pressure belt 52 was reduced to its target level of 110° C.
The result of the conventional method is indicated by multiplication signs in FIG. 6 . In the case of the conventional method, a substantial number of sheets of thick paper 2 were continuously conveyed through the fixing device 9 up to 0 minute 0 second, and then, the air blowing fan 203 was activated at 0 minute 0 second while the pressure belt 52 was kept in contact with the fixation belt 51 . Thus, heat was removed from the fixation belt 51 by the pressure belt 52 which was being cooled while remaining in contact with the fixation belt 51 . The temperature of the fixation belt 51 reduced to its target level of 170° C. in 11 seconds. However, while the fixation belt 51 was cooled, the pressure belt 52 was kept in contact with the fixation belt 51 , being thereby increased in temperature to 140° C. Consequently, it took additional 20 seconds to reduce the temperature of the pressure belt 52 to its target level. In other words, a total downtime of 30 seconds was necessary to ready the fixing device 9 for fixation.
If the recording medium is switched from thick paper to thin paper immediately after a substantial number of sheets of thick paper are continuously conveyed through the fixing device 9 , it is necessary to cool both the fixation belt 51 and pressure belt 52 .
If the conventional method is used in this situation, the pressure belt 52 is increased in temperature while the fixation belt 51 is cooled by the pressure belt 52 which is kept pressed upon the fixation belt 51 . Thus, the amount of time it takes for the temperature of the pressure belt 52 to reach its target level becomes longer, even though the conventional method reduces the amount of time it takes to cool the fixation belt 51 .
In this experiment, a comparative method for cooling the fixation belt 51 and pressure belt 52 was studied. In the case of the comparative method, the pressure belt 52 was cooled while it was kept separated by a minute distance from the fixation belt 51 . In other words, the fixation belt 51 was naturally cooled through the heat radiation therefrom, for the following reason. That is, in the case of the comparative method, only the pressure belt 52 is cooled, with the presence of a minutes distance between the fixation belt 51 and pressure belt 52 . However, the fixation belt 51 is higher in temperature than the pressure belt 52 . Thus, as the supply of electric power to the first heating element 201 is stopped, the fixation belt 51 relatively quickly reduces in temperature.
The result of the usage of the conventional method is indicated by rhombic signs in FIG. 6 . In the case of the comparative method, a substantial number of sheets of thick paper 2 were continuously conveyed through the fixing device 9 from 59 minute 30 second to 0 minute 0 second. Then, the air blowing fan 203 was activated at 0 minute 0 second, to remove heat only from the pressure belt 52 while keeping a small distance between the fixation belt 51 and pressure belt 52 as shown in FIG. 4( b ). In this case, it took only three seconds for the temperature of the pressure belt 52 to reduced to its target level of 110° C. However, it took 43 seconds for the fixation belt 51 to be cooled to its target temperature level by the natural heat radiation.
Table 3 is a summary of FIG. 6 , regarding the lengths of time required for the fixing device 9 (image forming apparatus 100 ) to become ready for an image forming operation in which the recording medium is thin paper, immediately after 200 sheets of thick paper 2 were continuously conveyed for image formation.
TABLE 3
Cooling method
Cooling durations
Fixing
Pressing
Fixing
Pressing
Waiting time
Emb 1
Fan cooling
21 sec
5 sec
21 sec
Comp. Ex
No
Fan cooling
43 sec
3 sec
43 sec
Prior art
Press-contact
Fan cooling
11 sec
30 sec
30 sec
Referring to Table 3, in the case of the conventional cooling method, the air blowing fan 203 was used to cool only the pressure belt 52 , whereas in the case of the cooling method in this embodiment, the air blowing fan 203 was combined with the mechanism 207 for pivotally moving the pressure belt 52 , to make it possible to cool both the fixation belt 51 and pressure belt 52 . In the case of the cooling method in the first embodiment, therefore, the fixation belt 51 and pressure belt 52 were simultaneously cooled, which made the cooling method in this embodiment shorter in the total amount of time necessary to reduce the temperatures of the fixation belt 51 and pressure belt 52 to their target levels than the conventional cooling method, and the comparative cooling method in which either the fixation belt 51 or pressure belt 52 is cooled through natural heat radiation.
FIG. 7 is a drawing for illustrating the results of an experiment in which the cooling method in this embodiment, comparative cooling method, and conventional cooling method were tested in effectiveness after the thin paper was selected as the recording medium while the image forming apparatus was kept on standby. In the case of the cooling method in this embodiment, the pressure belt 52 was pivotally moved as shown in FIG. 4 to confirm the effectiveness of the cooling method in this embodiment after thin paper was selected as the recording medium.
Referring to Table 2, the default setting for the standby target temperature is 180° C. for the fixation belt 51 , and 100° C. for the pressure belt 52 . Next, referring to Table 1, the referential values for the highest temperature levels at image forming operation in which thin paper is the recording medium can be started is 165°C/110°C (fixation belt/pressure belt.) Therefore, both the fixation belt 51 and pressure belt 52 had to be cooled before it became possible for thin paper to be used as the recording medium.
The results of the controlling (cooling) method in this embodiment are indicated by round black dots (bold line) in FIG. 7 . In the case of the control in this embodiment, the image forming apparatus 100 was kept on standby until 0 minute 0 second, and the fixation belt 51 and pressure belt 52 began to be cooled at 0 minute 0 second, with the pressure belt 52 kept separated from the fixation belt 51 as shown in FIG. 4( a ). The temperature of the fixation belt 51 reduced to a target level of 165° C. with the elapse of 13 seconds. Then, the pressure belt 52 was placed close to the fixation belt 51 as shown in FIG. 4( b ), and the pressure belt 52 was cooled. At this point in time, however, the temperature of the pressure belt 52 had reduced to 100° C. Therefore, the job in which thin paper was used as the recording medium was started at the same time as the cooling of the fixation belt 51 was completed.
The result of the conventional control is represented by the multiplication signs in FIG. 7 . In the case of the conventional control, the image forming apparatus 100 was kept on standby until 0 minute 0 second, and the cooling of the fixation belt 51 was started at 0 minute 0 second through the pressure belt 52 which was in contact with the fixation belt 51 . As a result, the pressure belt 52 was increased in temperature, requiring no less than 10 seconds to cool the pressure belt 52 .
The comparative control is represented by rhombic dots. The image forming apparatus 100 was kept on standby until 0 minute 0 second, and only the pressure belt 52 began to be cooled at 0 minute 0 second, with the presence of a small distance between the fixation belt 51 and pressure belt 52 . As for the fixation belt 51 , the electric power supply to the first heating element 201 for the fixation belt 51 was stopped so that the fixation belt 51 was cooled by natural heat radiation. As a result, it took 40 seconds to cool the fixation belt 51 .
Table 4 is a summary of the lengths of time it took for the controls in this embodiment, comparative control, and conventional control to ready the image forming apparatus 100 , which was kept on standby, for a printing operation which used thin paper as the recording medium.
TABLE 4
Cooling method
Cooling durations
Fixing
Pressing
Fixing
Pressing
Waiting time
Emb 2
Fan cooling
13 sec
No
13 sec
Comp. Ex
No
Fan cooling
40 sec
No
40 sec
Prior art
Press-contact
Fan cooling
8 sec
20 sec
20 sec
Referring to Table 4, even in the case in which the target temperatures were switched while the image forming apparatus 100 was kept on standby, the control in this embodiment simultaneously cooled both the fixation belt 51 and pressure belt 52 . Therefore, the control in this embodiment was substantially shorter in downtime than the comparative and conventional controls which left the cooling of either the fixation belt 51 or pressure belt 52 to natural heat radiation.
As described above, in the case in which the target temperatures for the fixation belt 51 and/or pressure belt 52 are switched during the execution of a “serial job”, that is, a job made up of a serial combination of small jobs which are different in the recording medium, or while the image forming apparatus 100 is kept on standby, the control in this embodiment operates the image forming apparatus 100 in the first cooling mode. Therefore, it is very effectively to cool the fixation belt 51 while preventing the excessive increase in the temperature of the pressure belt 52 , which is one of the causes of the formation of unsatisfactory images by the image forming apparatus 100 .
In the first cooling mode, the pressure belt 52 is kept separated from the fixation belt 51 by a substantial distance. Therefore, the airflow generated toward the fixing device 9 by the air blowing fan 203 can simultaneously cool both the fixation belt 51 and pressure belt 52 by flowing between the fixation belt 51 and pressure belt 52 . In the second cooling mode, the pressure belt 52 is kept separated from the fixation belt 51 by only a small distance. Therefore, the airflow generated toward the fixing device 9 by the air blowing fan 203 is concentrated upon the pressure belt 52 , cooling therefore only the pressure belt 52 . That is, in this embodiment, the pressure belt 52 can be changed in attitude to control the distance between the fixation belt 51 and pressure belt 52 . Therefore, both the fixation belt 51 and pressure belt 52 , or only the pressure belt 52 , can be cooled by the air blowing fan 203 without requiring the air blowing fan 203 to be changed in the direction in which the air blowing fan 203 generates airflow.
Further, in this embodiment, the temperature of the center portion of the fixation belt 51 in terms of the lengthwise direction of the fixation belt 51 , and the temperature of the center portion of the pressure belt 52 in terms of the lengthwise direction of the pressure belt 52 , are detected, and the distance between the fixation belt 51 and pressure belt 52 is controlled by changing the pressure belt 52 in attitude according to the target temperatures of the fixation belt 51 and pressure belt 52 . Therefore, both the fixation belt 51 and pressure belt 52 , or only the pressure belt 52 , can be selectively cooled. Therefore, the control in this embodiment can make the temperature of the fixation belt 51 and that of the pressure belt 52 reach their target levels within the least amount of time, that is, as quickly as possible, within the range of the cooling capacity of the air blowing fan 203 .
Incidentally, the fixing device 9 in this embodiment is structured so that, first, (a) the pressure belt 52 is changed in attitude by the pressure belt pivoting mechanism 200 , and then, (b) the airflow generated by the air blowing fan 203 is changed in direction with the use of the aforementioned airflow direction changing member 21 . However, this embodiment is not intended to limit the present invention in terms of the structure of the fixing device 9 . For example, the fixing device 9 may be structured so that the airflow can be simply changed in direction, that is, toward the pressure belt 52 , or the space between the fixation belt 51 and pressure belt 52 , (b) by changing the airflow direction by the airflow direction changing member 210 , or (a) by changing the surface of the pressure belt 52 in position with the use of the pressure belt pivoting mechanism 200 .
<Embodiment 2>
Next, the second embodiment of the present invention is described. However, the features of the fixing device 9 in this embodiment, which are the same in description as the counterparts in the first embodiment, are not described; only the differences of the second embodiment from the first embodiment are described. FIG. 8 is a drawing for describing the belt cooling system in the second embodiment. FIG. 9 is a drawing for describing how the airflow generated by the air blowing fan 203 is changed in cooling area. FIG. 10 is a drawing for describing the cooling effect of the belt cooling system in the second embodiment. The second embodiment can prevent the problem that the portions of the fixation belt 51 , which are out of the recording medium path, from increasing in temperature. Therefore, it can reduce the length of time a user has to wait until the portions of the fixation belt 51 , which are out of the recording medium path cool down.
During a printing operation, the control section 141 keeps the pressure belt 52 in contact with the fixation belt 51 , and controls the fixation belt 51 in temperature based on Table 1 which shows the target temperature levels for the fixation belt 51 and pressure belt 52 according to the recording medium type, with the use of the temperature control section 200 . The temperature control section 200 controls the temperature of the fixation belt 51 based on the temperature level detected by the first temperature detection which is positioned at the center of the fixation belt 51 in terms of the widthwise direction of the fixation belt 51 . Therefore, as a substantial number of sheets of the recording medium are continuously conveyed through the fixing device 9 , the widthwise edge portions of the fixation belt 51 , that is, the portions of the fixation belt 51 , which are outside the recording medium path, gradually increase in temperature. As described above, the temperature control section 200 controls the first heating element so that the amount by which the fixation belt 51 is supplied with heat by the first heating element equals the amount by which heat is robbed from the recording medium path portion (center portion) of the fixation belt 51 by the recording medium. Therefore, the widthwise edge portions of the fixation belt 51 , or the out-of-sheet-path portions of the fixation belt 51 , which are not robbed of heat by the sheets of the recording medium, are made to increase in temperature by the heat supplied by the first heating element 201 .
In the second embodiment, therefore, the fixing device 9 is provided with an airflow direction controlling member 208 in addition to the air blowing fan 203 so that while sheets of the recording medium are conveyed through the fixing device 9 , the widthwise edge portions of the pressure belt 52 are cooled by the combination of the air blowing fan 203 and airflow direction controlling member 208 , to indirectly cool the out-of-sheet-path portions of the fixation belt 51 , which are in contact with the widthwise edge portions of the pressure belt 52 , in order to prevent the out-of-sheet-path portions of the fixation belt 51 from excessively increasing in temperature.
Referring to FIG. 8 , the fixing device 9 in the second embodiment is provided with the airflow direction controlling member 208 , which is fixed in its positional relationship to the pressure belt 52 . The airflow direction controlling member 208 , which is an example of an airflow blocking member, is positioned so that it faces the center range of the pressure belt 52 to reduce the air blowing fan 203 in the ratio of the amount of the air blown toward the center range of the pressure belt 52 in the second cooling mode. That is, the airflow direction controlling member 208 is a structural component of the fixing device 9 in this embodiment, which is for removing heat from the out-of-sheet-path portions of the pressure belt 52 , in the second cooling mode, that is, the cooling mode in which the pressure belt 52 is kept in contact with the fixation belt 51 .
The airflow direction controlling member 208 is solidly positioned so that its positional relationship relative to the aforementioned pair of pivotally movable plates 113 which are at the lengthwise ends of the rotational axis of the pressure belt 52 , one for one, does not change. The pressure belt 52 , pressure roller 102 , pressure pad 106 , tension roller 104 , and airflow direction controlling member are attached to the pivotally movable plate 113 , making up a pressure application unit which is can be pivoted together with the pivotally movable pressure application plate 113 about the axis 111 .
Like the pressure belt 52 , pressure roller 102 , second heating element 202 in the pressure roller 52 , and second temperature detection element 206 , the airflow direction controlling member 208 also is attached to the pivotally movable pressure application plate 113 , with the unshown frame formed of metallic plate, making up an integral part of the pressure application unit. A user can place the pressure belt 52 in contact with the fixation belt 51 , or optionally set the distance between the fixation belt 51 and pressure belt 52 by pivotally moving the pivotally movable pressure application plate 113 , with the use of the pressure belt pivoting mechanism 207 .
Referring to FIG. 8( a ), the airflow direction controlling member 208 is positioned so that when the pressure belt 52 is kept separated from the fixation belt 51 , the airflow direction controlling member 208 does not block the airflow generated by the air blowing fan 203 in the direction to flow along the pressure belt 52 to cool the fixation belt 51 . Therefore, the airflow is not blocked by the airflow direction controlling member 208 , reaching thereby both the fixation belt 51 and pressure belt 52 as shown in FIG. 9( a ). The cooling effect of the first cooling mode, that is, the mode in which the image forming apparatus 100 is operated in a case where the target temperatures for the fixation belt 51 and/or pressure belt 52 are switched during the “serial job” described in the description of the first embodiment, or while the image forming apparatus 100 is kept on standby, is not lost.
Next, referring to FIG. 8( b ), the airflow direction controlling member 208 is positioned so that while the pressure belt 52 is kept in contact with the fixation belt 51 , the airflow generated by the air blowing fan 203 in the direction of the pressure belt 52 is prevented from hitting the central range of the pressure belt 52 in terms of the widthwise direction of the pressure belt 52 . That is, the airflow direction controlling member 208 is positioned so that while the pressure belt 52 is kept in contact with the fixation belt 51 , the airflow generated by the air blowing fan 203 in the direction of the pressure belt 52 is made to flow on the outward side of the airflow direction controlling member 208 in terms of the widthwise direction of the member 208 , and cools the widthwise edge portions of the pressure belt 52 as shown in FIG. 9( b ). Therefore, the problem that the widthwise edge portions of the fixation belt 51 , more specifically, the portions of the fixation belt 51 , which are outside the recording medium path, excessively increase in temperature, can be prevented by operating the image forming apparatus 100 in the second cooling mode, with the air blowing fan 203 activated, to cool the edge portions of the pressure belt 52 in terms of the widthwise direction of the pressure belt 52 .
FIG. 10( a ) is a drawing for describing the cooling effect of the second cooling mode in the second embodiment. It shows how effectively the widthwise end portions of the pressure belt 52 were cooled. In the experiment performed to test the effect of the second cooling mode, the temperature distribution of the fixation belt 51 in terms of the direction parallel to the axial line of the fixation belt driving roller 101 was obtained immediately after 1,000 sheets of ordinary paper, which were A4 in size and 200 g in basis weight, were continuously conveyed through the fixing device 9 in the portrait position. Incidentally, when a sheet of ordinary paper, which is A4 in size is conveyed in the portrait position, the portions of the fixation belt 51 , which are outside the recording medium path, are larger, and therefore, are more likely to excessively increase in temperature, than when the sheet is conveyed in the landscape position.
The conditions under which the experiment was carried out were 350 mm in the width of the opening of the air blowing fan 203 , 140 mm in the width of the airflow direction controlling member 208 , 400 mm in the width of the fixation belt 51 , and 185 mm in the length of the fixation belt 51 . Further, the target temperature for the fixation belt 51 was set to 190° C., and the rated highest temperature level for the fixation belt 51 , which was set based on the expected durability of the fixation belt 51 , was 220° C. Ordinarily, as the detected temperature level of the fixation belt 51 reaches 220° C., the recording medium conveyance is temporarily stopped. Then, it is started as the detected temperature level of the fixation belt 51 falls below 220° C. However, the experiment was for testing the temperature control in the second embodiment. Therefore, in order to accurately evaluate the temperature increase of the fixation belt 51 across its out-of-sheet-path portions, 1,000 sheets of paper were continuously conveyed without temporarily stopping the recording medium conveyance, even when the detected temperature level of the fixation belt 51 exceeded 220° C.
Given in Table 5 are the results of the experiment in which the control in the second embodiment (which operates the image forming apparatus 100 in the second cooling mode during an image forming operation in which sheets of paper are continuously conveyed), conventional control (which does not activate the air blowing fan 203 during an image forming operation in which sheets of paper are continuously conveyed), and comparative control (which cools the entire surface of the pressure belt 52 by activating the air blowing fan 203 , during an image forming operation in which sheets of paper are continuously conveyed), were tested.
TABLE 5
Temperature rise
prevention at end
No. of processed
Cooling
Max.
portions (1000
sheets up to design
range
temp.
sheets)
temp.
Emb. 2
Opposite
212° C.
G
≧1000
ends
Comp.
Whole
226° C.
NG
500
Ex.
surface
Prior art
No
224° C.
NG
700
Referring to FIG. 10( b ), in the case of the second embodiment, the image forming apparatus 100 was operated in the second cooling mode in an image forming operation in which a substantial number of sheets of paper were continuously conveyed. As a result, even in an image forming operation in which 1,000 sheets of paper were continuously conveyed, the temperature of the out-of-sheet-path portions of the fixation belt 51 was prevented from exceeding 212° C. In comparison, in the case of the conventional control which does not activate the air blowing fan 203 during an image forming operation in which a substantial number of sheets of paper are continuously conveyed, the temperature of the out-of-sheet-path portions of the fixation belt 51 reached as high as 224° C.
Further, in the case of the comparative fixing device which does not have the airflow direction controlling member 208 , and cooled the entirety of the pressure belt 52 by activating the air blowing fan 203 , during an image forming operation in which a substantial number of sheets of paper were continuously conveyed, the out-of-sheet-path portions of the fixation belt 51 became higher in temperature than those of the conventional fixing device, for the following reason. That is, in the case of the comparative fixing device, the central portion of the fixation belt 51 , that is, the portion of the fixation belt 51 , which was being controlled in temperature, was cooled. Thus, the first heating element 201 was increased in load, being thereby made to generate more heat. Consequently, the amount of the heat which the out-of-sheet-path portions of the fixation belt 51 were given also increased. Also in the case of the comparative fixing device, both the temperatures of the fixation belt 51 and pressure belt 52 had to be kept at their target levels. Thus, the comparative fixing device was greater in the amount of electric power consumption than the fixing device in the second embodiment; electrical power was wastefully consumed.
By the way, in reality, the fixing device 9 is provided with a third temperature detecting element (thermistor), which is positioned in contact with one of the out-of-sheet-path portions of the fixation belt 51 , so that as the detected temperature of the out-of-sheet-path portion reaches 220°, which is the highest level in terms of the temperature rating of the fixation belt 51 , the sheet conveyance is temporarily stopped to idle the image forming apparatus 100 until the out-of-sheet-path portions of the fixation belt 51 cool down to 200° C. When the temperature of the out-of-sheet-path portions of the fixation belt 51 is 220° C., it takes roughly three minutes for the out-of-sheet-path portions of the fixation belt 51 to cool down to 200° C. In other words, roughly 3 minutes are wasted.
In the case where the image forming apparatus 100 was operated in the second cooling mode, the out-of-sheet-path portions of the fixation belt 51 did not reach 220° C., or the highest temperature level which the fixation belt 51 can withstand from the standpoint of design. Thus, even during an image forming operation in which 1,000 sheets of paper were continuously conveyed through the fixing device, the apparatus 100 was not idled even once for cooling. In comparison, in the case of the conventional fixing device, the temperature of the out-of-sheet-path portions of the fixation belt 51 reached once to 220° C., or the highest temperature level which the fixation belt 51 can with stand from the stand point of its design, and the apparatus 100 had to be idled for roughly 3 minutes for cooling. In the case of the comparative fixing device, the temperature of the out-of-sheet-path portions of the fixation belt 51 reached twice 220° C., or the highest temperature level which the fixation belt 51 can with stand from the standpoint of its design, and the apparatus 100 had to be idled for roughly six minutes; a user had to wait roughly 6 minutes.
As described above, in the case of the fixing device in the second embodiment, it is provided with the airflow direction controlling member 208 , and the excessive increase in the temperature of the out-of-sheet-path portions of the fixation belt 51 is prevented by operating the image forming apparatus 100 in the second cooling mode, that is, the cooling mode in which the pressure belt 52 is kept in contact with the fixation belt 51 . Thus, the out-of-sheet-path portions of the fixation belt 51 are very effectively prevented from excessively increasing in temperature even during a job in which a substantial number of sheets of recording medium are continuously conveyed. In other words, the second embodiment of the present invention can improve a fixing device (image forming apparatus) in terms of the length of time the image forming apparatus has to be idled (user has to wait) to cool the out-of-sheet-path portions of the fixation belt 51 .
The above-described experiment proved the effectiveness of the second embodiment of the present invention, that is, the second embodiment can eliminate various problems attributable to the excessive temperature increase which occurs to the out-of-sheet-path portions of the fixation belt 51 during the execution of an image forming apparatus in which a substantial number of sheets of recording paper are continuously conveyed through the fixing device.
In the case of the fixing devices in the first and second embodiments, the heating nip, in which a sheet of the recording medium is heated, is formed by placing the pressure belt 52 in contact with the fixation belt 51 (heating belt). However, the first and second embodiments are not intended to limit the present invention in terms of the structure of a fixing device. For example, the present invention is also effectively applicable to a fixing device structured so that a pressure belt 52 A is placed in contact with a heat roller 51 A ( FIG. 11 ).
Referring to FIG. 11( b ), a heat nip N is formed by pressing the pressure belt 52 A upon the fixation roller 51 A. The fixing device 9 A is structured so that the pressure belt 52 A can be pivotally moved, like the pressure belt 52 in the first embodiment, by the pressure belt pivoting mechanism 207 . In the first cooling mode, the pressure belt 52 A is kept separated from the fixation roller 51 A, and the airflow which moves along the pressure belt 52 A cools the fixation roller 51 A, as shown in FIG. 11( a ). In the second cooling mode, the pressure belt 52 A is kept a minute distance away from the fixation roller 51 A, and therefore, the airflow generated by the air blowing fan 203 in the direction of the fixation roller 51 A is blocked by the pressure belt 52 A.
In the preceding embodiments of the present invention, the image forming apparatus was a color printer of the tandem type, and also, of the intermediary transfer type. That is, the image forming apparatus was structured so that image forming stations were aligned in tandem along the intermediary image bearing member. However, these embodiments are not intended to limit the present invention in terms of the structure of an image forming apparatus. For example, the present invention is also applicable to a color printer of the intermediary transfer/single drum type, which sequentially forms multiple monochromatic images, different in color, on its single image bearing member, and transfers the toner images onto its intermediary transfer member, a color printer of the tandem/direct transfer type, which does not have an intermediary transfer member, and directly transfers multiple monochromatic toner images, different in color, from its image bearing member onto a sheet of the recording medium. Moreover, the present invention is also applicable to an image forming apparatus other than a printer. That is, it is applicable to a copying machine, a facsimile machine, etc.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
This application claims priority from Japanese Patent Application No. 184295/2011 filed Aug. 26, 2011, which is hereby incorporated by reference. | An image heating apparatus includes a heating roller; a belt forming a heating nip; a heating device for heating the heating roller; a controller for controlling a temperature of the heating roller at temperature depending on thickness of sheet; an air feeding device for feeding air to the belt; an executing portion capable of executing an operation in a mode in which the air feeding device feeds the air into between the belt and the heating roller while the belt is spaced from the heating roller with the belt and the heating member being rotating. When a thin sheet is fed following a thick sheet, the executing portion executes the operation in the mode after the thick sheet passes through the nip and before the thin sheet is fed into the nip. | 6 |
RELATED APPLICATION
This is a continuation-in-part of our earlier filed and copending patent application U.S. Ser. No. 751,641, filed Dec. 17, 1976 now U.S. Pat. No. 4,126,891.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a switching regulator, especially the type comprising a chopper circuit and a DC-DC converter.
2. Description of the Prior Art
A conventional switching regulator serves the purpose of controlling DC output voltage by means of switching elements such as transistors which enable the ON/OFF operation of the pulse. The benefits of this system are a smaller loss of power, better performance, and compactness in design.
The most typical types now available on the market are the chopper circuit type and the DC-DC converter. There is also a combination of these two features to ensure a better control of DC output voltage against an erratic AC power source.
However, they must be equipped with pulse operation in the chopper circuit to make the switching operation possible, and with an isolator for high voltage insulation such as a photocoupler in the feedback circuit from the DC-DC converter to the chopper circuit. All these additions make the system a complicated one and expensive as well.
SUMMARY OF THE INVENTION
An object of the present invention is to eliminate the above mentioned disadvantages. Another object of the present invention includes the combination of the chopper circuit.
Another object is to obtain the synchronizing signals of the chopper circuit from the inverter of the DC-DC converter. This could be realized only after achieving the combination of the chopper circuit and the DC-DC converter.
Another object of the present invention is to eliminate the isolator in the voltage feedback circuit installed between the chopper circuit and the DC-DC converter.
Another object of the present invention is the addition of a detecting winding which detects at the output of the inverter in the DC-DC converter.
According to one example of the present invention, a switching regulator is provided, which includes:
(a) a DC voltage source circuit;
(b) a chopper circuit for receiving the output signal from the DC voltage source circuit and producing a first pulse signal which is smoothed by a low pass filter so as to obtain a first DC voltage at the output terminal thereof;
(c) a DC-DC converter circuit which at least includes an inverter circuit for receiving the first DC voltage of the chopper circuit and producing a second pulse signal which is rectified by a rectifier circuit so as to obtain a second DC voltage to be adapted to supply it to a load; and
(d) a feedback circuit supplying a control signal from the inverter circuit to the chopper circuit so as to control the ON/OFF operation of the chopper circuit in response to said control signal.
The other objects, features and advantages of the present invention will be apparent from the following description taken in conjunction with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the conventional switching regulator;
FIG. 2 is a block diagram showing an embodiment of this present invention;
FIG. 3 is an electrical circuit showing an example of a chopper circuit used in the switching regulation according to the present invention;
FIG. 4 is an electrical circuit of a DC-DC converter used in the switching regulation according to the present invention;
FIGS. 5a to 5e and FIGS. 5c' to 5e' show waveforms at various points in the above circuits to explain the performance of this invention;
FIG. 6 is a block diagram of an alternative embodiment for the system illustrated in FIG. 2; and
FIG. 7 is a schematic diagram illustrating the alternative embodiment of the system of FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preceding the explanation of the present invention, the conventional switching system is explained.
A conventional switching regulator (such as FIG. 1) supplies a DC signal to the switching circuit 2 after having rectified the AC input 1a in the rectifier circuit 1. This DC signal is switched and converted into an AC signal, which, while passing through the low pass filter 3, changes into DC. This DC voltage is applied to the inverter 4. The output of the inverter is rectified at the rectifier circuit 6 which is connected to the transformer 5, and the regulated DC voltage (not shown in the figure) is supplied to the load. At the same time the DC output insulates the primary and the secondary of the output transformer by an isolator 7, and feedback to the pulse width modulator 8 for the stabilization of the output voltage.
The pulse width modulator 8 has connected thereto a pulse generator 9 to generate a triangular wave or sawtooth wave. A decrease or increase in the DC output voltage mentioned above affects the pulse and changes its width. This serves to supplement changes of the output voltage and make it possible to stabilize the DC output voltage.
So, the conventional switching regulator, like the one explained above, requires a pulse generator 9 which provides pulse width modulation. Also, a relatively expensive coupler is required to insulate the DC output of the rectifier circuit 6 from the pulse width modulator 8. Moreover, the DC output is supplied directly to the pulse width modulator 8, and this could cause variations in the operation of the feedback circuit.
The present invention eliminates all of these inconveniences or performance defects of the conventional switching regulator. The present invention eliminates the need for the isolator and the pulse generator but still provides good voltage regulation.
Now, the present invention is described in detail by way of some preferred embodiments thereof with reference to the accompanying drawings.
FIG. 2 is the block diagram showing one embodiment of the present invention. In this figure A is the chopper circuit, B indicates the entire system of the DC-DC converter, 10 indicates the rectifier circuit to rectify the AC input 10a, 11 indicates the switching circuit to convert the output of the rectifier circuit to an AC signal, 12 indicates the low pass filter, 13 indicates the inverter, 14 indicates the output transformer, 15 indicates the rectifier circuit from which the regulated DC voltage output is obtained, and 16 is a winding for detecting feedback voltage which is different from the above mentioned secondary winding of the output transformer. Winding 16 serves to detect the output corresponding to variations of the output voltage and adds it to the pulse modulator 18 via the voltage feedback circuit 17.
On the other hand, the output transformer 14 connected to the output side of the above-mentioned inverter 13 has a detecting winding 19 to detect the signals to synchronize with the inverter output. The detected synchronizing signals are applied to the pulse width modulator 18 via the synchronizing signal detector 20 equipped with an integral circuit and other systems.
In accordance with the detected variations recorded as the pulse width of the DC output, the switching time of the switching circuit 11 is controlled. This is the manner by which the regulated voltage DC output is obtained.
The rectifier circuit 10, switching circuit 11, low pass filter 12, and pulse width modulator constitute the chopper circuit A. The inverter 13, output transformer 14 and the rectifier circuit 15 constitute the DC-DC converter B.
The possibility of using the chopper circuit A and DC-DC converter B in FIG. 2 as circuits shown in FIG. 3 and FIG. 4 will be explained hereinafter.
FIG. 3 shows the chopper circuit A of FIG. 2. This chopper circuit A receives a DC output through the circuit rectifier 10 which rectifies the AC input. The DC output is connected into a constant DC output voltage via the switching circuit 11 and the low pass filter 12. For this purpose, the feedback voltage will be used by the detecting winding 16 of the output transformer 14 on the output side of the inverter 13 in order to control the switching circuit 11. The output signal of the inverter 13 is detected by the detecting winding 19, and that will be the switching signal for the chopper circuit A.
The PWM signal to control the switching circuit 11 comprises the synchronizing signal and the feedback voltage; that is, the DC output (+Epc) obtained by rectifying the AC input is switched by Darlington-connected transistors Q1, Q2 and Q3, into an AC pulse signal, and, after smoothing by low pass filter 12 consisting of choke coil L1 and capacity C3, is supplied to the inverter 13.
The DC-DC converter B supplies a square wave pulse synchronizing signal (FIG. 5(a)) to the base of one of the transistors Q4 and Q5 of the differential amplifier via an integrating circuit made of resistor R8 and capacity C2 (FIG. 5(b)).
From the detecting winding 16 of the DC-DC converter B, a DC voltage corresponding to the regulated voltage DC output will be applied to the base of the transistor Q5 via the variable resistor R9.
Therefore, the base of transistor Q5 gets output (FIG. 5(c)) that is a sum of the feedback voltage of the return voltage detecting winding 16 and the triangular signal, such as the integrated output of the synchronizing signal.
In this manner, by comparing in the differential amplifier the output with the reference voltage Vz on the base of transistor Q4, the pulse width modulation signal shown in FIG. 5(d) can be obtained at the collector of the transistor Q4.
Current I 1 (FIG. 5(e)) corresponding to the pulse width modulation signal runs through the collector of the switching transistor Q3 and is applied to the inverter 13 via the choke coil L1 which makes up low pass filter 12.
In this block diagram, D1 shows the diode which permits a rapid flow of energy in the choke coil L1; D2 shows the Zener diode which establishes the reference voltage for the operation of transistor Q4; R6 and R7 show damping resistors of transistor Q4 and Q5; and R1 shows the driving resistor of the chopper circuit A to place transistor Q4 ON when the power is being supplied. R2 shows the resistor which provides the Zener diode D2 with the driving current to make it operate properly.
In the above embodiment, when too much load is presented to the output side of the rectifier circuit 15, the voltage from the detecting winding 16 is reduced, so that the type of signal illustrated in FIG. 5(c) to FIG. 5(e) can be obtained to increase the output voltage of rectifier circuit 15. In this way, DC output voltage is consant no matter how erratic the load.
Next, the construction and performance of the DC-DC converter B is described with reference to FIG. 4.
The output from the chopper circuit A, such as the DC output of the low pass filter 12, is converted into AC by transistors Q6 and Q7, and generates the pulse voltage at the primary coil 14A of the output transformer 14. Here, when the output from the chopper circuit A is supplied, the transistor Q9 of the starter S begins to operate. At the same time, capacitor C7 is charged, and transistor Q8 is ON. By discharging electricity charged to capacitor C7, driving coil l 1 as a starting winding is energized, a control coil secondary windup (one of the control coils l 2 and l 3 that are connected to transistors Q6, Q7) is energized, so that oscillation starts.
Once the oscillation is started, there will be no rapid changes of voltage in capacitor C7. The base of transistor Q8 will have an inverse bias through diode D3 and D4, and this oscillation starting circuit is cut off. Winding l v of driver transformer T1 is a primary winding thereof and connects through resistor R12 to output transformer winding 19.
In this way, the inverter continues to oscillate and generates square waves of predetermined frequency in the circuit including coil l 2 and l 3 and capacitor C4 and C5. Its output is rectified by the rectifying circuit with diodes D5 and D8 and capacitors C9 and C10 via the secondary coil of the output transformer 14, and finally made into the DC output of the regulator voltage.
The above-mentioned square wave output is supplied to the previously described feedback voltage detecting winding 16 and the synchronizing signal detecting winding 19. From the feedback voltage detecting winding 16, the DC voltage corresponding to the regulated DC output voltage is obtained in insulation from the DC output circuit through the rectifying circuit consisting of diodes D9 to D12 and capacitor C8. This DC voltage is supplied to the pulse width modulator 18 of the chopper circuit through the voltage return circuit.
From the synchronizing signal detecting winding 19 a synchronizing pulse corresponding to the frequency mentioned above is obtained and supplied to the pulse width modulator 18 through the synchronizing signal detection circuit.
T1 shows the driving transformer and T2 shows the transformer for feedback of current.
By choice of the capacitor C3 and resistor R13 in the above circuit, and establishing the appropriate time constant, the follow up speed can be made variable.
Thus, the voltage feedback loop is formed on the secondary side of the output transformer 14 (apart from the circuit which creates the regulated DC output voltage) through the detecting winding for the feedback voltage, and therefore the operation is stabilized against input variations on the secondary side.
The voltage for the inverter 13 can be chosen so that the transistors Q6 and Q7 are used at a predetermined voltage. This also means that the system can be applicable to any power source and voltage.
As described above, the present invention has the following features. The chopper circuit has a switching circuit which is supplied with DC voltage and can be controlled by the output of the pulse width modulator. A DC-DC converter is connected to the chopper circuit and is equipped with an inverter, an output transformer, and a rectifier circuit for the supply of load voltage. A synchronizing signal detecting circuit detects a synchronizing signal from the output of the output transformer to synchronize the pulse modulator. A voltage feedback circuit is provided to control the pulse width according to a control voltage obtained by rectifying an output of the output transformer, the rectified output then being fed to the pulse width modulator.
In accordance with the present invention, the need for an isolator such as a photo-coupler has been eliminated along with the square wave generator needed to accompany the system in the conventional switching regulator, also contributing to constancy of the regulated voltage against change in the AC input voltage.
Referring now to FIG. 6 of the drawings, an alternative embodiment of the system shown in the block diagram of FIG. 2 is illustrated. In this embodiment, the output of the low pass filter 12 is not only coupled to the inverter 13 but also to a voltage feedback circuit 30 which connects with the pulse width modulator 18.
Referring now to FIG. 7, it is noted that the output from the low pass filter 12 at the output end of inductor L1 connects not only to the DC input of the inverter 13 but also to the voltage feedback circuit 30 having a potentiometer R31 connected in series with a resistor R32 to -Epc. The center arm of the variable resistance R31 connects to the input of transistor Q5. The remainder of the circuit elements illustrated are similar to that previously described for FIGS. 3 and 4.
With the system shown in FIGS. 6 and 7, the total cost is reduced by eliminating the feedback voltage detecting winding 16 and the voltage feedback circuit 17. Also, the regulation characteristics of the modified circuit do not deteriorate in accordance with a reduction in the winding resistance of the output transformer 14 and using inverter transistors which have low ON resistance.
In the modified circuit, the output of the detecting winding 19 is also applied to the base of transistor Q8 in the starter circuit through diodes D3, D4 in order to cut it off after the inverter starts. The output of the detecting winding 19 is also connected to the voltage feedback winding labeled l v through the resistor R12. This voltage feedback insures operation of the inverter in cooperation with a current feedback transformer T2 when a load connected to the rectifier circuit 15 is heavy.
Although various minor modifications may be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of our contribution to the art. | A switching regulator includes a chopper circuit and a DC-DC converter. A switching signal for use with the chopper circuit is derived from an inverter portion of the DC-DC converter so as not to use an external pulse oscillator. A DC voltage feedback circuit is provided from the output of the DC-DC converter to the chopper circuit so as to stabilize the DC output signal of the DC-DC converter. Alternatively, the DC voltage feedback is provided from an output of the chopper circuit. | 7 |
BACKGROUND
This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
A blowout preventer is a large, specialized valve used to seal, control and monitor oil and gas wells. Blowout preventers are designed to cope with extreme erratic pressures and uncontrolled flow emanating from a well during drilling. Pressure kicks can lead to the uncontrolled release of oil and/or gas from a well resulting in a potentially subsea well event known as a blowout. Blowout preventers are critical to the safety of crew, equipment and environment, and to the monitoring and maintenance of well integrity. While blowout preventers are intended to be fail-safe devices, accidents may still occur if the blowout preventer fails to properly operate. For example, during the Apr. 20, 2010, Deepwater Horizon drilling rig explosion, it is believed that the blowout preventers may not have properly operated and/or were not activated in a timely fashion. In addition to loss of well control the wellhead equipment was damaged creating obstacles to recovering control of the well.
SUMMARY
In accordance to an aspect of the disclosure a subsea well safing package or system includes an assembly connector interconnecting a lower assembly and an upper assembly, the lower assembly is to be connected to a subsea well and includes lower slips to engage and secure a tubular suspended in a bore formed through the lower assembly and the upper assembly, the upper assembly having upper slips operable to engage and secure the tubular, and a shear positioned between the upper slips and the lower slips operable to shear the tubular. In accordance to aspects of one or more embodiments the well safing package is connected to a subsea well, for example the subsea wellhead. In accordance to an aspect of one or more embodiments the subsea well safing package is connected between the marine riser and a subsea well. In accordance to one or more aspects the subsea well safing package is connected between the marine riser and a blowout preventer stack that is connected to the subsea wellhead.
A method in accordance to one or more aspects includes securing a tubular suspended in a bore with lower slips of a lower assembly, securing the tubular in the bore with upper slips of an upper assembly, shearing the tubular in the bore between the positions at which the tubular is secured with the lower slips and the upper slips, and after shearing the tubular, disconnecting the upper assembly from the lower assembly.
The foregoing has outlined some of the features and technical advantages in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims of the invention. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.
FIG. 1 a schematic illustration of a subsea safing system according to one or more aspects of the disclosure utilized in a subsea well drilling system.
FIG. 2 depicts a subsea safing system according to one or more aspects, wherein the safing sequence has been initiated and the marine riser and upper safing package are physically and hydraulically disconnected from the lower safing package, the BOP stack, and the well.
FIG. 3 illustrates a subsea well safing assembly according to one or more aspects of the disclosure.
FIG. 4A-4B is a flow chart of a subsea well safing sequence according to one or more aspects of a subsea well safing system.
FIGS. 5-17 are schematic diagrams of safing sequence operations according to one or more aspects of a subsea well safing system.
FIG. 5A is a sectional view of a vent system according to one or more aspects shown along the line I-I of FIG. 5 .
FIG. 8A is a sectional view of a shutter device shown along the line I-I of FIG. 8 .
FIG. 8B is a sectional, side view of a shutter device in accordance to one or more aspects.
FIG. 13A illustrates the marine riser and upper safing package disconnected and separated from the lower safing package and the wellhead in response to progression of the subsea well safing sequence.
DETAILED DESCRIPTION
It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
As used herein, the terms “up” and “down”; “upper” and “lower”; “top” and “bottom”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as the top point and the total depth of the well as the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.
In this disclosure, “hydraulically coupled” or “hydraulically connected” and similar terms, may be used to describe bodies that are connected in such a way that fluid pressure may be transmitted between and among the connected items. The term “in fluid communication” is used to describe bodies that are connected in such a way that fluid can flow between and among the connected items. It is noted that hydraulically coupled may include certain arrangements where fluid may not flow between the items, but the fluid pressure may nonetheless be transmitted. Thus, fluid communication is a subset of hydraulically coupled.
A subsea well safing system is disclosed to provide a means for mitigating the environmental and economic damage that can result from the loss of control of a well, such as occurred in the Macondo well being drilled from the Deepwater Horizon on 20 Apr. 2010. According to one or more aspects, the subsea well safing system provides a mechanism to separate the marine riser from the blowout preventer stack and the well in a manner intended to mitigate the physical damage to the well drilling system and to enhance the potential for successfully reconnecting to the well, for example via the BOP stack, to regain control of the well.
FIG. 1 is a schematic illustration of a subsea well safing system, generally denoted by the numeral 10 , being utilized in a subsea well drilling system 12 . In the depicted embodiment drilling system 12 includes a BOP stack 14 which is landed on a subsea wellhead 16 of a well 18 (i.e., wellbore) penetrating seafloor 20 . BOP stack 14 conventionally includes a lower marine riser package (“LMRP”) 22 and blowout preventers (“BOP”) 24 . The depicted BOP stack 14 includes subsea test valves (“SSTV”) 26 . As will be understood by those skilled in the art with benefit of this disclosure, BOP stack 14 is not limited to the devices depicted.
Subsea well safing system 10 includes a safing package, or assembly, generally referred to herein as a catastrophic safing package (“CSP”) 28 that is landed on BOP system 14 and operationally connects a marine riser 30 extending from platform 31 (e.g., vessel, rig, ship, etc.) to BOP stack 14 and thus well 18 . CSP 28 includes an upper CSP 32 and a lower CSP 34 that are configured to separate from one another in response to initiation and implementation of a safing sequence thereby disconnecting marine riser 30 from the BOP stack 14 and well 18 , for example as illustrated in FIG. 2 . The safing sequence is initiated in response to parameters indicating the occurrence of a failure in well 18 with the potential of leading to a blowout of the well. Subsea well safing system 10 may automatically initiate the safing sequence in response to the correspondence of monitored parameters to selected safing triggers. CSP 28 may include an accumulator 29 , see e.g. FIGS. 3 and 7 , hydraulically connected to wellhead 16 to operate the wellhead connector lock as further described below. In FIG. 7 , wellhead accumulator 29 is depicted as a standalone, accumulator located proximate to seafloor 20 and wellhead 16 .
Wellhead 16 is a termination of the wellbore at the seafloor and generally has the necessary components (e.g., connectors, locks, etc.) to connect components such as BOPs 24 , valves (e.g., test valves, production trees, etc.) to the wellbore. The wellhead also incorporates the necessary components for hanging casing, production tubing, and subsurface flow-control and production devices in the wellbore.
BOP stack 14 commonly includes a set of two or more BOPs 24 utilized to ensure pressure control of well 18 . A typical stack might have one to six ram-type preventers and, optionally, one or two annular-type preventers. A typical stack configuration has the ram preventers on the bottom and the annular preventers at the top. The configuration of the stack preventers is optimized to provide maximum pressure integrity, safety and flexibility in the event of a well control incident. For example, one set of rams may be fitted to close on the drillpipe, blind rams to close on the open hole, and another set of shear rams to cut and hang-off the drillpipe. It is also common to have an annular preventer at the top of the stack to close over a wide range of tubular (e.g., drillpipe) sizes and the open hole. BOP stack 14 also includes various spools, adapters, and piping ports to permit circulation of wellbore fluids under pressure in the event of a well control incident.
LMRP 22 and BOP stack 14 are coupled together by a wellbore connector that is engaged with a corresponding mandrel on the upper end of BOP stack 14 . LMRP 22 typically provides the interface (i.e., connection) of the BOPs 24 and the bottom end 30 a of marine riser 30 via a riser connector 36 (i.e., riser adapter). Riser connector 36 may include a flex joint that provides for a range of angular movement of riser 30 (e.g., 10 degrees) relative to BOP stack 14 , for example to compensate for vessel 31 offset and current effects along the length of marine riser 30 . Riser connector 36 may include one or more ports for connecting fluid (i.e., hydraulic) and electrical conductors, i.e., communication umbilical, which may extend along (exterior or interior) marine riser 30 from the drilling platform located at surface 5 to subsea drilling system 12 . For example, it is common for a hydraulic choke line 44 and a hydraulic kill line 46 to extend from the surface for connection to BOP stack 14 .
Marine riser 30 is a tubular string that extends from the drilling platform 31 down to well 18 . The marine riser is in effect an extension of the wellbore extending through the water column to drilling vessel 31 . The marine riser diameter is large enough to allow for drillpipe, casing strings, logging tools and the like to pass through. For example, in FIGS. 1 and 2 , a tubular 38 (e.g., drillpipe) is illustrated deployed from drilling platform 31 into marine riser 30 . Drilling mud and drill cuttings can be returned to surface 5 through marine riser 30 , for example through the annulus between drillpipe and the riser. Communication umbilicals (e.g., hydraulic, electric, optic, etc.) can be deployed exterior to or through marine riser 30 to CSP 28 and BOP stack 14 . A remote operated vehicle (“ROV”) 124 is depicted in FIG. 2 and may be utilized for various tasks.
Refer now to FIG. 3 which illustrates a subsea well safing package 28 in accordance to an aspect of one or more embodiments. CSP 28 depicted in FIG. 3 is further described with reference to FIGS. 1 and 2 . The illustrated CSP 28 has an upper CSP 32 and a lower CSP 34 . Upper CSP 32 includes a riser connector 42 which may include a riser flange connection 42 a , and a riser adapter 42 b which may provide for connection of communication umbilicals and extension of the communication umbilicals to various CSP 28 devices and/or BOP stack 14 devices. For example, a choke line 44 and a kill line 46 are depicted extending from the surface with riser 30 and extending through riser adapter 42 b for connection to the choke and kill lines of BOP stack 14 . The illustrated CSP 28 includes a choke stab 44 a and a kill line stab 46 a for interconnecting the upper portion of choke line 44 and kill line 46 with the lower portion of choke line 44 and kill line 46 . As will be further described below with reference to safing sequence 86 , stabs 44 a , 46 a also provide for disconnecting from the stab and kill lines during a safing operations and during subsequent recovery and reentry operations reconnecting to the choke and kill lines via stabs. The riser connector 42 may include a flex joint.
CSP 28 has an internal longitudinal extending bore 40 , depicted in FIG. 3 by the dashed line through lower CSP 34 , for passing tubular 38 . Annulus 41 is formed between the outside diameter of tubular 38 and the inside diameter of bore 40 .
Upper CSP 32 includes slips 48 (i.e., safety slips) to close on tubular 38 and secure tubular 38 in the upper assembly. Slips 48 are actuated in the illustrated system by hydraulic pressure from an accumulator 50 . Depicted CSP 28 includes a plurality of hydraulic accumulators 50 which may be interconnected in pods, such as upper accumulator pod 52 . As will be understood by those skilled in the art with benefit of the present disclosure, accumulators 50 may be provided in various configurations. The depicted accumulators 50 are hydraulically charged and do not require connection to a hydraulic source at the surface. It will also be recognized by those skilled in the art that hydraulic pressure may be provided from the surface. In this embodiment, accumulators 50 located in the upper accumulator pod 52 are at least hydraulic connected to slips 48 . The pressure in accumulators 50 can be monitored and accumulators 50 may be actuated in sequence as needed to ensure that adequate hydraulic pressure is available to actuate CSP devices such as slips 48 .
Lower CSP 34 includes a connector 54 to connect to the subsea well, rams 56 (e.g., blind rams), high energy shears 58 , lower slips 60 (e.g., bi-directional slips), and a vent system 64 (e.g., valve manifold). In FIGS. 1 and 2 CSP 28 is illustrated connected to the subsea well and wellhead through BOP stack 14 , for example, via riser connector 36 of the LMRP 22 . Vent system 64 may include one or more valves 66 . Vent system 64 is depicted with vent valves (e.g., ball valves) 66 a , choke valves 66 b , and one or more connection mandrels 68 . Valves 66 b can be utilized to control fluid flow through connection mandrels 68 . For example, a recovery riser 126 is depicted connected to one of mandrels 68 for flowing effluent from the well and/or circulating a kill fluid (e.g., drilling mud) into the well as further described below. Vent system 64 is further described below with reference to FIGS. 5 and 5A .
Lower CSP 34 is depicted in FIG. 3 with a deflector or shutter device 70 (e.g., impingement device) disposed above vent system 64 and below lower slips 60 , shears 58 and blind rams 56 . Lower CSP 34 includes a plurality of hydraulic accumulators 50 that are arranged and connected in one or more lower hydraulic pods 62 for operations of various devices of CSP 28 . As will be further described below, CSP 28 may be operationally connected to a chemical source 76 , e.g. methanol, to mitigate hydrate formation. For example, a chemical such as methanol may be injected in lower CSP 34 to prevent hydrate formation for example when vents 66 are opened.
Upper CSP 32 and lower CSP 34 are detachably connected to one another by a connector 72 . CSP connector 72 includes a first connector portion 72 a and a second mandrel connector portion 72 b which are illustrated for example in FIG. 13A , for example a collet connector. An ejector device 74 (e.g., ejector bollards) is operationally connected between upper CSP 32 and lower CSP 34 to separate upper CSP 32 and marine riser 30 from lower CSP 34 and BOP stack 14 after connector 72 has been actuated to the unlocked position. The depicted CSP 28 also includes a plurality of sensors 84 which can sense various parameters, such as and without limitation, temperature, pressure, strain (tensile, compression, torque), vibration, and fluid flow rate. Sensors 84 further includes, without limitation, erosion sensors, position sensors, and accelerometers and the like. Sensors 84 can be in communication with one or more control and monitoring systems, for example as further described below, forming a limit state sensor package.
CSP 28 includes a control system 78 , which may be located subsea for example at CSP 28 , or at a remote location such as at the surface. Control system 78 may include one or more controllers that may be located at different locations. For example, a depicted control system 78 includes an upper controller 80 (e.g., upper command and control data bus) and a lower controller 82 (e.g., lower command and controller bus). Control system 78 may be connected via conductors (e.g., wire, cable, optic fibers, hydraulic lines) and/or wirelessly (e.g., acoustic transmission) to various subsea devices and to surface (i.e., drilling platform 31 ) control systems.
With reference to FIGS. 3 to 17 , depicted control system 78 includes upper controller 80 and lower controller 82 . Each of upper and lower controllers 80 , 82 may have a collection of real-time computer circuitry, field programmable gate arrays (FPGA), I/O modules, power circuitry, power storage circuitry, software, and communications circuitry. One or both of upper and lower controller 80 , 82 may include control valves.
One of the controllers, for example lower controller 82 , may serve as the primary controller and provide command and control sequencing to various subsystems of safing package 28 and/or communicate commands from a regulatory authority for example located at the surface. The primary controller, e.g., lower controller 82 , contains communications functions, and health and status parameters (e.g., riser strain, riser pressure, riser temperature, wellhead pressure, wellhead temperature, etc.). One or more of the controllers may have black-box capability (e.g., a continuous-write storage device that does not require power for data recovery).
Upper controller 80 is described herein as operationally connected with a plurality of sensors 84 positioned throughout CSP 28 and may include sensors connected to other portions of the drilling system, including along riser 30 , at wellhead 16 , and in well 18 . Upper controller 80 , using data communicated from sensors 84 , continuously monitors limit state conditions of drilling system 12 . According to one or more embodiments, upper controller 80 , may be programmed and reprogrammed to adapt to the personality of the well system based on data sensed during operations. If a defined limit state is exceeded an activation signal (e.g., alarm) can be transmitted to the surface and/or lower controller 82 . A safing sequence may be initiated automatically by control system 78 and/or manually in response to the activation signal.
With reference to FIGS. 4A and 4B , a safing sequence 86 according to one or more aspects of subsea well safing system 10 is illustrated. In sequence block 88 , the safing sequence is initiated in response to monitoring the limit state sensor 84 package for example by upper controller 80 . In sequence block 90 , pressure is vented from CSP 28 by opening a valve 66 a in vent system 64 , see, e.g., FIGS. 1 , 3 , 5 and 5 A. In sequence block 92 , the choke and kill lines are closed to prevent combustibles from flowing up from the well and to the surface through the kill and choke lines, see, e.g., FIGS. 1 , 3 and 6 . In sequence block 94 , the wellhead 16 connector lock is pressurized to prevent accidental ejection of BOP stack 14 from wellhead 16 , see, e.g., FIGS. 3 and 7 . In sequence block 96 , fluid flowing up from the well is diverted, e.g., partially diverted, to the open vents to prevent erosion of CSP elements such as the slips 48 , 60 , see, e.g., FIGS. 1 , 3 , 8 , 8 A and 8 B. For example, fluid flow may be diverted by operating a deflector or shutter device 70 to a closed position. The rams of device 70 may act to center the tubular in the bore of the safing assembly prior to securing the tubular with the slips and/or prior to shearing the tubular. In sequence block 98 , tubular 38 is secured in lower CSP 34 by closing lower slips 60 (e.g., bi-directional slips), see, e.g., FIGS. 1 , 3 and 9 . In sequence block 100 , tubular 38 is secured in upper CSP 32 by closing upper slips 48 (e.g., safety slips), see, e.g., FIGS. 1 , 3 and 10 . In sequence block 102 , tubular 38 is sheared in lower CSP 34 by activating shears 58 , see, e.g., FIGS. 1 , 3 and 11 . In sequence block 104 , upper CSP 32 and lower CSP 34 are disconnected from one another by operating CSP connector 72 to a disconnected position, see, e.g., FIGS. 1 , 3 , 12 and 13 A. In sequence block 106 , marine riser 30 and upper CSP 32 are physically separated (e.g., ejected) from lower CSP 34 and BOP stack 14 by activating ejector device 74 (i.e., ejector bollards), see, e.g., FIGS. 1-3 , 13 , and 13 A. In sequence block 108 , (see, e.g., FIGS. 1-3 and 14 ) blind rams 56 are closed to seal bore 40 (see, e.g. FIG. 3 ) and shut-off the fluid flow from the subsea well into the environment. In sequence block 110 , hydrate formation in lower CSP 34 is treated by injecting methanol, see, e.g., FIGS. 1-3 and 15 . In sequence block 112 , the open valves 66 a in vent system 64 are closed, see e.g., FIGS. 1-3 and 16 . In sequence block 114 , a formation stability test is performed, see, e.g., FIGS. 1-3 and 17 .
FIG. 5 is a schematic diagram of sequence block 90 , according to one or more embodiments of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . In response to initiating safing sequence 86 , one or more vent valves 66 a of vent system 64 are opened. Valves 66 a are opened to reduce the flow of fluid through the annulus 41 between tubular 38 and the CSP 28 walls forming bore 40 through CSP 28 (see FIG. 3 , the dashed lines in lower CSP 34 ) and lowering the backpressure on lower slips 60 . The open and closed position of vent valves 66 a can be verified by a control signal from each valve position sensor 84 . An accumulator 50 located in the assigned accumulator pod 62 can be activated to provide hydraulic power to the valve actuators 116 of controller 82 . Lower controller 82 continuously monitors the pressure at accumulator pod 62 and activates additional accumulators 50 as may be required to maintain working pressure. With reference to FIGS. 5-17 , the active device (e.g., accumulators, valves, slips, shears) of the depicted sequence block is emphasized by hatching.
FIG. 5A is a sectional view of an embodiment of vent system 64 shown along the line I-I of FIG. 5 . FIG. 5A depicts two vent valves 66 a on each side of vent system 64 , which are depicted in the closed position. Valves 66 b are positioned to control flow through connection mandrels 68 . In the depicted embodiment, the sensor 84 located proximate to the connection mandrel 84 is an accelerometer.
FIG. 6 is a schematic diagram of sequence block 92 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . In sequence block 92 , valves 118 positioned in each of choke line 44 and kill line 46 are actuated from the open to the closed position to prevent combustibles from flowing up the choke line 44 and the kill line 46 .
FIG. 7 is a schematic diagram of sequence block 94 according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . Controller 82 initiates the pressurization of wellhead connector lock 120 to prevent the accidental ejection of BOP stack 14 from wellhead 16 due to the high back pressure encountered in subsequent sequence blocks, e.g., when device 70 is closed, slips 48 , 60 are closed, and due to the loss of hydraulic pressure to wellhead connector lock 120 when marine riser 30 is disconnected from BOP stack 14 disconnecting any hydraulic sources extending along marine riser 30 to CSP 28 .
FIG. 8 is a schematic diagram of sequence block 96 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 3 , 8 A and 8 B. In sequence block 96 , controller 82 actuates device 70 to a closed position (see FIG. 8A ) in response to applying hydraulic pressure for example from a hydraulic accumulator 50 of lower accumulator pod 62 . In the closed position, device 70 can divert fluid flowing from the well to vent system 64 and to open vent valves 66 a and away from passing through annulus 41 of safing package 28 . The closed device 70 depicted in FIG. 8A , protects CSP 28 from the high flow rates and entrained solids that are encountered thereby limiting erosion of devices of CSP 28 , such as upper safety slips 48 and lower slips 60 . Deflector device 70 may be provided in various manners and configurations. Referring to FIG. 8A , tubular 38 is depicted substantially centered within bore 40 by device 70 , which is coaxial with bore 40 of CSP 28 , by rams 70 A, 70 B, and 70 C. According to at least one embodiment, closure of rams 70 A, 70 B, 70 C does not seal annulus 41 . In the embodiment depicted in FIG. 8B , each of rams 70 A, 70 B and 70 C comprises stacked and spaced apart plates 71 which interleave portions of the plates 71 of the adjacent rams.
FIG. 9 is a schematic diagram of sequence block 98 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . In sequence block 98 , controller 82 actuates lower slips 60 (e.g., bi-directional slips) securing tubular 38 within lower CSP 34 in preparation for sequence block 102 . In some embodiments, lower slips 60 may include deflector armor to divert fluid flow toward vent system 64 instead of, or in addition to, the use of device 70 described for example with reference to sequence block 96 and FIGS. 8 , 8 A, and 8 B.
FIG. 10 is a schematic diagram of sequence block 100 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . In sequence block 100 , upper slips 48 are actuated to engage tubular 38 within upper CSP 32 . In this embodiment, sequence block 100 is actuated by upper controller 80 . As with other sequence blocks, the controller monitors the pressure status of accumulators 50 and if a low pressure is detected, a subsequent accumulator in a pod is activated to actuate the sequence block device (i.e., slips 48 in sequence block 100 ).
FIG. 11 is a schematic diagram of sequence block 102 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 and 3 . After tubular 38 is engaged and secured respectively in upper CSP 32 (i.e., by slips 48 ) and lower CSP 34 (i.e., slips 60 ), lower controller 82 actuates shears 58 thereby shearing tubular 38 between upper slips 48 and lower slips 60 .
FIG. 12 is a schematic diagram of sequence block 104 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 2 , 3 and 13 A. In sequence block 104 , CSP connector 72 is actuated to the open or disconnected position permitting separation of upper CSP 32 from lower CSP 34 in sequence block 106 . In this embodiment, CSP connector 72 is actuated via upper controller 80 and hydraulic accumulators 50 located in upper accumulator pod 52 . In the depicted embodiment, CSP connector 72 is a collet comprising a first connector portion 72 a and a second connector portion 72 b , depicted for example in FIG. 13A . Second connector portion 72 b is disposed with lower CSP 34 and comprises a mandrel, identified individually by the numeral 72 c (see, FIGS. 13A , 14 - 17 ). The mandrel 72 c provides a mechanism for reconnecting, for example with a marine riser 30 , for re-entry into well 18 .
FIG. 13 is a schematic diagram of sequence block 106 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1-3 and 13 A. In sequence block 106 , depicted ejector devices 74 (i.e., ejector bollards) are actuated to physically separate upper CSP 32 and marine riser 30 from lower CSP 34 as depicted in FIGS. 2 and 13A . For example, ejector devices 74 may include piston rods 74 a which extend to push the upper CSP 32 away from lower CSP 34 in the depicted embodiment. FIGS. 2 , 13 A, and 14 - 17 illustrate piston rod 74 a in an extended position. In FIG. 13 , actuation of ejector devices 74 is provided by upper controller 80 and accumulator(s) 50 located in upper accumulator pod 52 .
Typically, marine riser 30 will be in tension which will assist in pulling the disconnected upper CSP 32 vertically away from lower CSP 34 which is connected to BOP stack 14 . In addition, the water currents and deflection in marine riser 30 (e.g., offset from platform 31 ) will assist in moving marine riser 30 and the separated upper CSP 32 laterally away from lower CSP 34 and the well. Choke line 44 and kill line 46 are disconnected respectively at choke stab 44 a and kill stab 46 a ( FIG. 3 ). Stabs 44 a and 46 b provide a mechanism for reconnection to surface sources during recovery operations.
In FIG. 13 , ejector device 74 is attached to lower CSP 34 and piston rods 74 a push against a portion of upper CSP 32 , for example a portion of the frame 122 of upper CSP 32 . It will be understood by those skilled in the art with benefit of this disclosure that ejector device 74 may be arranged in different configurations without departing from the scope of this disclosure. For example, ejector device 74 may be reversed so as to be attached with upper CSP 32 wherein piston rod 74 a acts against lower CSP 34 .
FIG. 14 is a schematic diagram of sequence block 108 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 2 and 3 . In sequence block 108 , blind rams 56 are actuated to the closed position sealing bore 40 (see FIGS. 3 and 8A , 8 B) to block any fluid that may be flowing up from well 18 through BOP stack 14 . The actuation of blind rams 56 may be provided by lower controller 82 and accumulator(s) 50 located in lower accumulator pod(s) 62 .
FIG. 15 is a schematic diagram of sequence block 110 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 2 and 3 . In sequence block 110 , methanol 76 may be injected into lower CSP 34 to prevent hydrate formation CSP 28 , in particular in the vents (e.g., vent valves 66 a ) of vent system 64 . The injection of methanol 76 may be provided for example by lower controller 82 and may be powered by accumulator(s) 50 located in lower accumulator pod(s) 62 .
FIG. 16 is a schematic diagram of sequence block 112 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 2 and 3 . In sequence block 112 , lower controller 82 actuates hydraulic power (e.g., accumulator 50 ) to actuate the open vent valves 66 a from the open to the closed position.
FIG. 17 is a schematic diagram of sequence block 114 , according to one or more aspects of subsea well safing system 10 , which is described with further reference to FIGS. 1 , 2 , and 3 . Subsequent to closing vent valves 66 a in sequence block 112 , lower controller 82 can initiate and perform a formation stability test for example by monitoring wellhead temperature and pressure via one or more sensors 84 .
If stable formation conditions are indicated, safing system 10 may be placed in a standby condition until recovery operations can be initiated and completed. If unstable formation conditions are indicated, vent valves 66 a may be opened to relieve pressure in an effort to prevent a subsurface blowout of well 18 , which will result in loss of the well and require more difficult and time consuming processes to plug well 18 . With effluent venting to the environment, a recovery riser 126 extending, for example from a vessel at surface 5 , may be connected to connection mandrel 68 of vent system 64 as depicted in FIG. 3 . ROV 124 ( FIG. 2 ) may be utilized to connect flexible riser 126 . A valve, such as valve 68 b , may be operated to the open position permitting flow of effluent through mandrel 68 of vent system 64 into recovery riser 126 and to the surface; and the open vent valves 66 a are operated to the closed position, thus providing a means to mitigate environmental damage until control of well 18 can be recovered.
According to at least one embodiment, a method of recovery of well 18 comprises closing in well 18 via lower CSP 34 and/or venting effluent from well 18 through vent system 64 and a recovery riser 126 to the surface. A marine riser 30 and choke line 44 and/or kill line 46 hydraulics are extended from the surface to lower CSP 34 . Choke and kill lines 44 , 46 can be connected to BOP stack 14 and well 18 via choke stab 44 a and kill stab 46 a which are located on lower CSP 34 which is still connected to well 18 . Marine riser 30 in some circumstances may be connected to connector mandrel 72 b of CSP connector 72 to reestablish hydraulic communication with well 18 through BOP stack 14 . Depending on the status of BOP stack 14 and formation stability, drilling mud may be circulated down one of marine riser 30 , kill line 46 , choke line 44 , and/or flexible riser 126 to kill well 18 .
According to one or more aspects, a subsea well safing package for installing on a subsea well includes a safing assembly connector interconnecting a lower safing assembly and an upper safing assembly, the safing assembly connector operable to a disconnected position. The lower safing assembly is configured to connect to the subsea well, for example via a blowout preventer stack and the upper safing assembly is configured to be connected to a marine riser. The lower safing assembly may include lower slips to engage a tubular suspended in a bore formed through the lower and the upper safing assemblies and the upper safing assembly may include upper slips operable to engage the tubular. A shear positioned between the upper slips and the lower slips is operable to shear the tubular.
According to one or more aspects a subsea well safing package is provided for installing on a subsea well having a safing assembly connector interconnecting a lower safing assembly and an upper safing assembly. The lower safing assembly including lower slips to engage and secure a tubular suspended in a bore formed through the lower and the upper safing assemblies and the upper safing assembly having upper slips operable to engage the tubular. A shear may be positioned between the upper slips and the lower slips to shear the tubular. The safing package may include an ejector device connected between lower safing assembly and the upper safing assembly that is operable to physically separate the upper safing assembly from the lower safing assembly. The ejector device may include an extendable piston rod.
The well safing package may include a vent operable between an open and a closed position. For example, the vent may be carried by the lower safing assembly and positioned below the lower slips when connected to the well.
A well safing package may include for example a vent carried by the lower safing assembly and positioned below the lower slips well and a deflector device positioned between the lower slips and the vent. The vent may be opened and the shutter device operated to a closed position to divert fluid flow toward the vent. In some embodiments the deflector device does not seal against the tubular suspended in the lower safing assembly.
A subsea well safing system according to one or more aspects includes a lower safing assembly connected to a subsea well and an upper safing assembly connected to a marine riser. A safing assembly connector interconnects the lower safing assembly and the upper safing assembly providing a bore therethrough in communication with the marine riser and the subsea well. An ejector device may be connected between the upper safing assembly and the lower safing assembly to physically separate the upper assembly and the connected marine riser from the lower safing assembly and the well.
The safing assembly may include, for example, lower slips operable to engage and secure a tubular suspended in the bore of the lower safing assembly and upper slips operable to engage and secure the tubular suspend in the bore of the upper safing assembly and a shear located between the lower slips and the upper slips operable to shear the tubular. A vent may be in communication with the bore and operable between a closed position and an open position. The safing system may include a deflector device located in the lower safing assembly between the lower slips and the vent that is operable to a closed position to divert fluid flow for example toward the vent.
A subsea well safing sequence includes utilizing a safing assembly installed between a subsea well and a marine riser. The safing assembly includes a lower safing assembly connected to the subsea well and an upper safing assembly connected to the marine riser, the safing assembly forming a bore between the marine riser and the subsea well. When the well safing sequence is initiated, securing a tubular that is suspended in the bore at a position in the lower safing assembly and securing the tubular at a position in the upper safing assembly. The tubular is sheared in the bore between the positions in the lower and the upper safing assemblies at which the tubular has been secured and physically separating the upper safing assembly and the connected marine riser from the lower safing assembly and the subsea well.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded. | A subsea well safing method and apparatus to secure a subsea well in the event of a perceived blowout in a manner to mitigate the environmental damage and the physical damage to the subsea wellhead equipment to promote the ability to reconnect and recover control of the well. The safing assembly is connectable to a subsea well and a marine riser. Pursuant to a safing sequence, the well tubular is secured in the upper and lower safing assemblies and the tubular is then sheared between the locations at which it has been secured. Subsequently, an ejection device may be actuated to physically separate the upper safing assembly and the connected marine riser from the lower safing assembly the subsea well. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to a dryer section for a paper machine which comprises at least dryer groups provided with single-wire draw. Each of the single-wire draw groups comprises a number of drying cylinders and a number of reversing cylinders or rolls arranged in the gaps between the drying cylinders. In each of the dryer groups, a web runs under constant contact with the wire over the drying cylinders and reversing cylinders or rolls so that the web enters into direct contact with the drying cylinders and the wire enters into direct contact with the reversing cylinders or rolls.
Currently the highest web speeds in paper machines are of an order of about 25 meters per second, but before long the speed range of from about 25 m/s to about 40 m/s is also likely to be realized. With the current highest speeds and with the future still higher speeds, in particular the dryer section has become and will be a bottle-neck for the runnability of a paper machine. With a view toward obtaining an adequate drying efficiency, the dryer section has often become long, which increases the costs of the dryer section and of the machine hall.
In the prior art, in multi-cylinder dryers of paper machines, twin-wire draw and/or single-wire draw is/are employed. In the former case, the groups of drying cylinders comprise two wires which press the web, one from above and the other one from below, against the heated cylinder faces of the drying cylinders. Between the rows of cylinders, which are usually horizontal rows, the web has free and unsupported draws which are susceptible of fluttering and which may result in web breaks. In the single-wire draw, each group of drying cylinders comprises a single drying wire on whose support the web runs through the whole group so that, on the drying cylinders, the drying wire presses the web against the heated cylinder faces, and on the reversing cylinders between the drying cylinders the web remains at the side of the outside curve, i.e., the drying wire is between the web and the outer surface of the reversing cylinders. Thus, in single-wire draw, the drying cylinders are placed outside the wire loop, and the reversing cylinders inside the loop. In the prior art normal groups with single-wire draw, the heated drying cylinders are placed in an upper row, and the reversing cylinders are placed in a lower row, the rows being generally horizontal and parallel to one another. So-called inverted groups with single-wire draw are also known, in which the heated drying cylinders are placed in the lower row and the reversing suction cylinders or rolls in the upper row, the substantial objective of an inverted group being to dry the web from the side opposite in relation to a normal group with single-wire draw.
In the area of the dryer section of a paper machine, various problems have occurred, of which in particular the large length of the dryer section should be mentioned. With respect to the prior art related to this, reference is made to U.S. Pat. No. 5,177,880, in which a dryer section of a paper machine is described which has been divided into a number of dryer groups, each of which groups comprises a number of drying cylinders, a number of reversing cylinders in the gaps between the adjacent cylinders, and a web support belt which runs around the cylinders in the dryer group. In each dryer group, the web runs under constant contact with the support belt over the drying cylinders and the reversing rolls so that the web enters into direct contact with the cylinders and that the support belt enters into direct contact with the reversing rolls. The cylinders are arranged in a number of rows, which rows are inclined in relation to the vertical direction alternatively rearward or forwards, thus defining V-shaped double rows. The cylinder placed at the end of each row and the cylinder placed at the beginning of the next row form a pair of cylinders, which cylinders are arranged horizontally side by side. The drying cylinders follow each other as a zig-zag line. Each inclined row comprises about three cylinders.
In the prior art, constructions are also known in which the cylinders are placed in vertical rows. One such construction is described in U.S. Pat. No. 4,972,608.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a dryer section of a paper machine whose length is shorter than existing dryer sections.
It is a further, particular object of the invention to provide a dryer section construction that is suitable for use in connection with modernizations of dryer sections of paper machines.
In view of achieving the objects stated above and others, the dryer section of a paper machine in accordance with the invention comprises groups with single-wire draw in the dryer section having at least four drying cylinders placed in pairs side by side and one above the other so that the upper pair of cylinders is placed at a lower level than the other cylinders in the group. As an important advantage of the present invention, a shorter length of the dryer section is achieved, in which case, for example in connection with modernizations of paper machines, as a result of the shorter length, in the space that remains in the final end of the dryer section, for example, a surface-sizing device and/or an afterdryer can be placed, whereby the quality of the paper produced can be improved. On the other hand, when new paper machines are constructed, by means of the shorter length of the dryer section, considerable economies are obtained as a result of the economies in the costs of the machine hall.
In a basic embodiment, the dryer section for a paper machine in accordance with the invention comprises a plurality of dryer groups with single-wire draw, each of the single-wire draw groups including drying cylinders, reversing cylinders arranged in gaps between adjacent ones of the drying cylinders, and a drying wire for carrying a web into direct contact with outer surfaces of the drying cylinders and such that the drying wire is situated between the web and outer surfaces of the reversing cylinders. At least one of the single-wire draw groups comprises at least four drying cylinders, first and second ones of the cylinders are arranged in a first horizontal level and third and fourth ones of the cylinders are arranged in a second horizontal level above the first horizontal level such that the axes of the first and third cylinders are situated in a first common substantially vertical column and the axes of the second and fourth cylinders are situated in a second common substantially vertical column, and at least one additional drying cylinder arranged at a horizontal level above the second horizontal level.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings are illustrative of embodiments of the invention and are not meant to limit the scope of the invention as encompassed by the claims.
FIG. 1 is a schematic illustration of a construction of a dryer group used in a dryer section in accordance with the present invention.
FIG. 2 is a schematic illustration of a second construction of a dryer group used in a dryer section in accordance with the present invention.
FIG. 3 shows a third dryer-group arrangement for use in a dryer section in accordance with the present invention.
FIG. 4 is a schematic illustration of a further exemplifying embodiment of a dryer group for use in a dryer section in accordance with the present invention.
FIG. 5 is a schematic illustration of an exemplifying embodiment of a dryer section in accordance with the present invention.
FIG. 6 shows a second exemplifying embodiment of a dryer section in accordance with the present invention.
FIG. 7 shows a further exemplifying embodiment of a dryer section in accordance with the present invention.
FIG. 8 shows a part of a dryer section composed of dryer groups shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the accompanying drawings wherein the same reference numerals refer to the same or similar elements, in accordance with the invention, a dryer group R comprises drying cylinders 10, reversing rolls 11, and a drying wire 15 which is guided by guide rolls 18. In the groups R, if necessary, it is also possible to employ blow boxes 16 in the gaps between the reversing cylinders 11. By means of the blow boxes 16, the intermediate spaces are air conditioned and evaporation from the web W is promoted. The faces of the drying cylinders 10 are kept clean by doctors 14. The drying wires 15 press the web W to be dried on the drying cylinders 10 against their smooth heated faces, and on the reversing cylinders 11, the web W remains at the side of the outside curve on the outer face of the wire 15. On the reversing cylinders 11, the web W is kept reliably on support of the wire 15 against the effects of centrifugal forces by the effect of the vacuum present in the grooved face of the reversing cylinders 11, whereby transverse shrinkage of the web W is also counteracted. As the reversing suction cylinders 11, preferably the suction cylinders marketed by the assignee under the trade mark "VAC-ROLL"™ are used, which have no inside suction boxes and with respect to the details of whose constructions reference is made to the assignee's U.S. Pat. No. 5,022,163, the specification of which is hereby incorporated by reference herein. However, it should be emphasized that the scope of the invention also includes dryer sections in which, in the positions of the reversing cylinders 11, conventional suction rolls provided with inside suction boxes and suction rolls of quite small diameters are employed.
In the dryer groups R in accordance with the present invention, underneath a tending platform 40, four drying cylinders 10 are placed in pairs in two vertical rows or columns, i.e., two cylinders placed one above the other such that their axes are in a substantially common vertical plane and two cylinders placed side by side in a substantially common horizontal plane. The four drying cylinders 10 below the tending platform 40 are placed so that their centers of rotation are placed at the corner points of a rectangle, preferably a square. The reversing cylinders or rolls 11 are placed in the gaps between adjacent pairs of drying cylinders 10 outside the rectangle. The portion consisting of the four drying cylinders 10 placed below may be placed in the beginning, around the middle, or in the end of the dryer group R. As shown, in the dryer groups R, at least one drying cylinder 10 is placed substantially at the level of the tending platform 40.
In the dryer group R as shown in FIG. 1, the first two drying cylinders 10 in the group R are placed one above the other in a vertical row 41, which is placed below the tending platform 40, and the following two drying cylinders 10 are placed at the side of the preceding two drying cylinders on corresponding horizontal levels 42, and the last two drying cylinders 10 in the group R are on the tending platform 40 side by side in the same horizontal plane. The difference in height H 1 between the center axes of the cylinders 10 on the tending platform 40 and the two cylinders 10 placed in the next lower plane is from about 1.5 m to about 3.5 m, preferably from about 2.2 m to about 3.0 m, and the difference in height H 2 between the axes of the cylinders 10 in the two lowest rows or levels 42 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m. The distances between the cylinders 10 are L 1 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, L 2 is from about 1.2 m to about 2.7 m, preferably from about 1.6 m to about 2.4, and L 3 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m. The diameter of the cylinders 10 is from about 1500 mm to about 2500 mm, preferably from about 1800 mm to about 2200 mm, and as the reversing cylinders 11, for example, Vac Rolls or suction rolls are used whose diameter is from about 600 mm to about 1800 mm, preferably from about 1200 mm to about 1500 mm. As shown in the figure, the cylinders 10 placed underneath the tending platform 40 are placed in pairs one below the other, in which case a favorable frame solution is obtained (See FIG. 8 in this regard). Further, the rubbish or broke coming from the doctors 14 of the cylinders 10 is directed away by means of a guide blowing or a guide plate (not shown). The drying wire 15 guides the paper web W over the reversing cylinder 11 onto the first drying cylinder 10 in the group R, from which the web W is passed to the cylinders 10 placed side by side in the lowest row 42. The web W is transferred from the last cylinder in the group R to the wire draw of the next group as a closed draw.
In this exemplifying embodiment of the invention, the last two cylinders 10, which are driven cylinders, are placed on the tending platform 40, and thus substantially at the level thereof, which permits a direct application of a drive arrangement which has been found to be good even at high speeds, in which the last two cylinders have a joint drive, auxiliary drive, by means of a suction roll placed between them or ahead of them. The placing of the drives on the tending platform is a construction which is quite favorable in view of the costs and of servicing.
With this exemplifying embodiment of the invention, compared with a conventional single-wire group, the length of the dryer group can be made about 30% shorter.
According to FIG. 2, the first four drying cylinders 10 in the dryer group R are placed, similarly to the exemplifying embodiment shown above in FIG. 1, below the tending platform 40 in pairs one below the other, and the last cylinder 10 in the group R is placed on the tending platform. From the last drying cylinder 10 in the group, the paper web W is passed to the wire draw of the next wire group R as a closed draw. The differences in height and distance between the rows 42/41 of cylinders are as follows: H 1 is from about 1.5 m to about 3.5 m, preferably from about 2.2 m to about 3.0 m, H 2 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, L 1 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, and L 2 is from about 1.2 m to about 2.7 m, preferably from about 1.6 m to about 2.4 m. The diameter of the cylinders 10 is from about 1500 mm to about 2500 mm, preferably from about 1800 mm to about 2200 mm, the diameter of the reversing cylinders 11 is from about 600 mm to about 1800 mm, preferably from about 1200 mm to about 1500 mm. In this exemplifying embodiment, the four "downstairs" cylinders 10 below the tending platform 40 are placed in pairs one below the other, and there is just one cylinder 10 on the tending platform 40, and which is the last drying cylinder in the dryer group. In this manner, a group R of five cylinders 10 is formed, which is particularly advantageous in the initial end of the dryer section, where traditionally fewer cylinders are used in the same drive group in order to secure the runnability.
FIG. 3 is substantially similar to the exemplifying embodiment shown in FIG. 2, but the reversing cylinders 11, preferably Vac Rolls, placed on the tending platform 40 and so also the lowest reversing roll 11 have diameters larger than those of the other reversing rolls which larger diameters are about 1000 to about 1800 mm, preferably from about 1500 mm to about 1800 mm, in which case larger drying-cylinder 10 covering angles are obtained and, thereby, better drying capacity. The diameters of the reversing cylinders 11 placed on the intermediate level are from about 600 mm to about 1200 mm, preferably about 1200 mm, in which case a favorable doctor-removing arrangement is obtained. This exemplifying embodiment, i.e. the use of reversing cylinders 11 of different sizes in the same dryer group R, can also be applied to the embodiment of the invention shown in FIG. 1. The differences in height and distance between the cylinder rows 42/41 are as follows: H 1 is from about 1.5 m to about 3.5 m, preferably from about 2.2 m to about 3.0 m, H 2 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, L 1 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, and L 2 is from about 1.2 m to about 2.7 m, preferably from about 1.6 m to about 2.4 m.
FIG. 4 shows a dryer-group arrangement in which the four downstairs cylinders 10 are placed in pairs one below the other, and in the upper row, on the tending platform 40 or substantially at the level thereof, in the horizontal direction, there are two drying cylinders 10, the first cylinder and the last cylinder in the group R. The paper web W is brought from the last drying cylinder of the preceding group R onto the first reversing cylinder 11 of the next group as a closed draw. Also in connection with the solution illustrated in this embodiment, it is possible to use the arrangement described in relation to the preceding figure, in which the diameters of the reversing rolls 11 are different. The differences in height and distance between the cylinder rows 42/41 are as follows: H 1 is from about 1.5 m to about 3.7 m, preferably from about 2.2 to about 3.2 m, H 2 is from about 1.6 m to about 2.7 m, preferably from about 1.9 m to about 2.5 m, L 1 is from about 1.6 m to about 2.7 m, preferably from about 1.9 to about 2.7 m, L 2 is from about 0.0 m to about 1.2 m, preferably from about 0.5 m to about 1.0 m, and L 3 is from about 2.2 m to about 4.5 m, preferably from about 3.0 m to about 4.0 m.
FIG. 5 shows an exemplifying embodiment of a dryer group as shown in FIG. 1, in which, with the exception of the first short group R 1 , a conventional portion with single-wire draw has been substituted for by groups R in accordance with the invention, and at the end, as the last dryer group, in view of securing a drying from both sides, there is a group R N with twin-wire draw. The "short" group R 1 has only about 4 drying cylinders. By means of this arrangement, compared with a conventional normal dryer section consisting only of groups with single-wire draw, an overall shortening of about 20% to about 22% of the length of the dryer section is achieved. In the arrangement illustrated here, there are "large" reversing rolls 11 on the tending platform 40.
FIG. 6 shows an embodiment consisting of dryer groups as shown in FIG. 1, in which the first group R 1 is a short group that applies a conventional normal single-wire draw, which group R 1 is followed by groups R in accordance with the invention, and in which, in view of securing a drying of the web W from both sides, an inverted group R N-1 is arranged as the second last dryer group in the dryer section and a normal group R N with single-wire draw is arranged as the last group in the dryer section. By means of this arrangement, a shortening of about 16% to about 18% is achieved relative to the conventional dryer section having only single-wire draw dryer groups. The inverted group R N-1 has the drying cylinders in the lower row and the reversing cylinders in an upper row above the lower row and functions to dry an opposite side of the web as in the normal dryer groups.
FIG. 7 shows an exemplifying embodiment of the arrangement as shown in FIG. 1, in which arrangement dryer groups R in accordance with the invention have been combined with so-called group-gap large cylinders 20, by whose means a drying from both sides is secured, and in which the last group R N is a normal group with single-wire draw. By means of this arrangement, a dryer section is obtained that is about 25% to about 30% shorter than a conventional dryer section that makes use of single-wire draw alone. The groups R N-3 , R N-1 with large cylinders have wire circulations of their own which are guided by wire guide rolls.
FIG. 8 shows an arrangement in which the frame arrangements for the exemplifying embodiment as shown in FIG. 1 are shown, consisting of vertical beams 100, horizontal beams 101, and auxiliary beams 102 for the reversing rolls 11.
The examples provided above are not meant to be exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims. For example, although only four drying cylinders are shown in the cylinder arrangement situated below the tending platform, it is understood that the four cylinders might be arranged at a different position with respect to the tending platform, and that the arrangement may include more than four cylinders arranged in the rows. | A dryer section for a paper machine including dryer groups with single-wire draw, each of which includes drying cylinders, reversing cylinders or rolls arranged in gaps between the drying cylinders, and a drying wire for carrying the web under constant contact with the wire over the drying cylinders and reversing cylinders or rolls so that the web enters into direct contact with the drying cylinders and that the wire enters into direct contact with the reversing cylinders or rolls. In at least one of the groups with single-wire draw in the dryer section, four drying cylinders are placed in pairs side by side and one above the other so that the upper pair of cylinders is placed at a lower level than the other cylinders in the group. | 3 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present invention is related to my co-pending U.S. patent application entitled “Leveling Rail Joints With Plane Support For Different Profiles”, filed of even date herewith, U.S. patent application Ser. No. ______, Attorney Docket No. 070867.000010, and “Leveling Rail Joints With Plane Support For Different Height Rails”, filed of even date herewith, U.S. patent application Ser. No. ______, Attorney Docket No. 070867.000011.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to rail joints for railroad track.
[0004] 2. Description of the Related Art
[0005] A railroad way is formed by joining two sets of parallel rails together, each set of rails formed of a number of rails connected lengthwise at their adjoining aligned ends. When one of the installed rails required replacement due to breakage, damage or completion of useful service life, the old installed rail has been replaced with a replacement or substitute rail, which could be a new or a used rail. In such cases, the replacement or substitute rail has often been a different height than that of the connecting rail to which connection was made.
[0006] So far as is known, it has been the practice to maintain the base portions of the replacement rail and the remaining rail of the original joint at a common level in the new joint being formed. This resulted in the upper surfaces of the head portions of the joined rails being at a different height. In these situations, however, there were impacts and shocks caused when the wheels of the engines and the rolling stock passed over the joint with the rail heads of different height. The repeated application of the resulting impacts so caused resulted in damage to the rails with resulting damage and loss of service life for the rails. There were also possible safety concerns.
SUMMARY OF THE INVENTION
[0007] Briefly, the present invention provides new and improved rail track structure formed at adjoining end portions of rails which have differing characteristics. The present invention provides a new and improved leveling joint connector bar for connecting adjoining end portions of rails of different height in a track structure. The adjoining end portions of the rails have an oblique surface formed below a head portion extending inwardly towards a web portion and an oblique surface on a foot portion extending inwardly towards the web portion. The leveling joint connector bar includes an elongate joint body spanning the adjoining end portions of the rails to be joined, and having a number of connector holes formed therein aligned with connector holes in the web portions of the adjoining end portions of the rails to be joined.
[0008] The elongate joint body member has an oblique upper surface formed with and extending along the length of the joint body, and the oblique upper surface is machined to conform to and engage with the oblique surface formed below the head portions of the adjoining end portions of the rails to be joined.
[0009] The elongate joint body member has an oblique lower surface formed with and extending along the length of a first segment of and conforming to and engaging with the oblique surface formed on the base portion of a first of the two rails to be joined. The elongate joint body member also an oblique lower surface formed with and extending along the length of a second segment of and conforming to and engaging with the oblique surface formed on the base portion of a second of the two rails to be joined.
[0010] The oblique upper surface of the elongate joint body member and the oblique lower surface of the first segment of the elongate joint body member are spaced from each a distance corresponding to the height of the first of the two rails to be joined, and the oblique upper surface of the elongate joint body member and the oblique lower surface of the second segment of the elongate joint body member are spaced from each a distance corresponding to the height of the second of the two rails to be joined.
[0011] The rail track structure includes a first track and a second segment having a web portion, a base portion and a head portion, the web portions of the first and second track segments having a number of connector holes formed therein for the passage of connectors at their end portions. The head portions of the first and second track segments each have an oblique surface formed below a head portion extending inwardly towards their web portions. The base portions of the first and second track segments also an oblique surface formed on a foot portion extending inwardly towards their web portions
[0012] An elongate connector bar is connected to span and join the adjoining end portions of the first and second track segments being joined, with a number of connector holes formed in the connector bar aligned with the connector holes in web portions of the adjoining end portions of the first and second track segments.
[0013] The elongate joint body member has an oblique upper surface formed with and extending along the length of the joint body. The oblique upper surface conforms to and engages with the oblique surface formed below the head portions of the adjoining end portions of the rails. The elongate joint body member has an oblique lower surface formed with and extending along the length of a first segment of and conforming to and engaging with the oblique surface formed on the base portion of a first of the two rails.
[0014] The elongate joint body member has an oblique lower surface formed with and extending along the length of a second segment of and conforming to and engaging with the oblique surface formed on the base portion of a second of the two rails to be joined. The oblique upper surface of the elongate joint body member and the oblique lower surface of the first segment of the elongate joint body member are spaced from each a distance corresponding to the height of the first of the two rails. The oblique upper surface of the elongate joint body member and the oblique lower surface of the second of the elongate joint body member are spaced from each a distance corresponding to the height of the second of the two rails.
[0015] The present invention provides new and improved leveling rail joints where the fitting, engagement and engagement with the rails being connected at their end portions is made by a set of joint or connector bodies that provide increased strength to the assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The characteristic details of the present invention are clearly shown in the following description and accompany figures, which illustrate this and provide points of reference to indicate the same parts in the figures shown.
[0017] FIG. 1 is a side view of a leveling rail joint according to the present invention for joining rails of different height characteristics.
[0018] FIG. 2 is a cross-sectional view taken along the lines 2 - 2 of the leveling rail joint of FIG. 1 .
[0019] FIG. 3 is a cross-sectional view taken along the lines 3 - 3 of the leveling rail joint of FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] In the drawings, the letter S designates generally a railroad track structure formed by a leveling rail joint L between a pair of adjacent track components, such as rail sections or segments R whose end portions E are to be joined. As will be set forth below, the adjoining end portions E of rails R which are joined by the leveling rail joint L have differing height characteristics.
[0021] Turning first to the rails R, the adjoining end portions E of the rails R to be joined have differing characteristics, in this case a different height. Each of the rails R has a web portion below a head portion 10 downwardly to a foot or base portion 12 . The end portions E are brought into engagement along their respective end surfaces 14 in forming the leveling rail joint L, as will be set forth.
[0022] As is evident in FIGS. 2 and 3 , a first rail 20 ( FIG. 2 ) of the rails R is of a greater height than a second rail 22 ( FIG. 3 ), due for example to the rails 22 having been in service for a period of time and rail 20 being newer. In some cases, the height difference is also in part due the result of a greater vertical of a web portion 24 of first rail 20 in comparison with web portion 26 of the second rail 22 . Typically, the rails 20 and 22 are of like or comparable profile. In other cases, the height of the head portion or the base portion, or both, of the rails R may differ and contribute to the different height characteristics of the rails R to be joined.
[0023] Each of the rails R is what is termed a standard rail and includes an oblique or slanting planar surface 30 formed on a lower surface 31 extending inwardly in a downward direction from a side surface 32 on each side of the head portion 10 of the rails R. The oblique surface 30 extends at a slanting or transverse angle with respect to the vertical axis of the rails R. The slope and the angle of surface 31 , as well as their extent in the rails R is in accord with appropriate rail industry standards for the particular rails being used based on the services conditions and the like.
[0024] Each of the rails R also includes an oblique or slanting planar upper surface 34 formed extending upwardly and inwardly from a side surface 35 of the foot or base portion 12 . The oblique surface 30 also extends at a slanting or transverse angle with respect to the vertical axis of the rails R. The slope and the angle of surface 34 and their extent in the rails R is also in accord with appropriate rail industry standards for the particular rails being used based on the services conditions and the like.
[0025] The leveling rail joint L according to the present invention is in the form of an elongate joint body 40 of sufficient length to span the adjoining end portions E of the rails R to be joined and provide requisite strength and support in the structure so formed. The length of the joint body 40 and its extent along the adjoining end portions E with which it is mounted are determined by the intended service or usage nature of the rails R and load bearing considerations.
[0026] The joint body 40 is formed of suitable strength alloy steel, depending upon the intended load and service usages of the rail structure S. Alloy steel bars are machined with flat planar surfaces to conform and engage corresponding planar surfaces of the rails R, as will be described, to form the joint body 40 . The joint body is elongate in the context of being of adequate extent along the rail joint between the rails R to provide adequate strength, support and durability during service life usage. This is determined by rail dimensions, and also intended service or usage nature of the rails, load bearing considerations and other rail design factors.
[0027] The joint body 40 has a suitable number of connector holes or ports 42 formed through it along its longitudinal extent. The connector holes 42 are spaced from each other along the joint body 40 at locations aligned with the connector holes 44 in web portions 24 and 26 of the adjoining end portions E of the rails R to be joined. It is preferable that the connector holes 42 be located on center points spaced no more than about four inches from each other along the extent of the joint body 40 for increased strength. If necessary, new connector holes may be formed in the web portions of the rails R according to the location of connector holes 42 in the joint body 40 .
[0028] The elongate joint body member 40 has an oblique upper surface 48 formed with and extending along the length of the joint body, and the oblique upper surface 48 is machined to conform to and engage with the oblique surface 30 formed below the head portions of the adjoining end portions E of the rails R to be joined.
[0029] The elongate joint body member 40 further has an oblique lower surface 50 ( FIG. 2 ) formed with and extending along the length of a first segment 54 to conform to and engage across its surface area with the oblique surface 34 formed on the base portion 12 of the rail 20 to be joined. The elongate joint body member 40 also has an oblique lower surface 56 ( FIG. 3 ) formed with and extending along the length of a second segment 58 to conform to and engage across its surface area with the oblique surface 30 formed on the base portion of the rail 22 to be joined.
[0030] Each of the oblique lower surfaces 50 and 56 of the joint body member 40 is also machined to conform to and engage the surfaces 30 on the rails 20 and 22 in forming the leveling rail joint L. Thus, each of the oblique planar surfaces of the joint body member 40 is in contact with a corresponding oblique planar surface on the corresponding rail end portion E to be engaged in forming the leveling rail joint L.
[0031] The oblique upper surface 48 of body member 40 and the oblique lower surface 50 of the segment 54 of the elongate joint body member 40 are spaced from each a distance indicated as D 1 ( FIG. 2 ) in the drawings, corresponding to the height of the web portion of the rail 20 to be joined. The oblique upper surface 48 of the joint body member 40 and the oblique lower surface 56 of the second segment 58 of body member 40 are spaced from each a distance D 2 ( FIG. 3 ) corresponding to the height of the web portion of rail 22 to be joined.
[0032] Thus with the rail joint L according to the present invention, the end portions E of the rails R are aligned as a common plane along upper surfaces 60 of the head portions 10 . Accordingly, as the wheels of traffic from engines and rolling stock pass over the joined rails, a level surface is present for the wheels to contact. In this way damage to the rails due to wheel impact on the rail joint with different height is substantially reduced with the present invention. In a number of cases, it is desirable to insert a shim or chuck or other support below the base portion of the shorter height rail and on the rail cross-tie as load bearing support for the joint L beneath the shorter height rail.
[0033] The joint body 40 takes the form of an inner portion 62 located between the head portion 10 and base 12 of the adjoining end portions E of the rail R inwardly of the side surface 32 of the head 10 . The joint body 40 also has a support segment 64 extending outwardly from the side surface 32 of the head portions 10 of the rails R to be joined to provide additional strength to the assembled leveling joint and rail end portions E. The support segment 64 includes a surface 66 extending downwardly away from the juncture of the planar surface 30 and side surface 32 of the head portion of the rail R. The support segment 64 has a vertical outer surface 68 extending downwardly to the outer edge of oblique lower surfaces 50 and 56 . The support segment 64 is at least as thick as the inner portion 62 of the joint body member 40 located below the head portion 10 of the rail R, and can be, if desired, as much as 150% thicker is cross-section than the inner portion 62 .
[0034] The joint body 40 shown in the drawings is configured to be installed on the outer side of rails R at end portions E to form a composite joint for what is known as a left hand joint, where the first rail 20 of greater height than the second rail 22 is to the left of rail 22 when one is facing the centerline of the track. For a right-hand joint, the joint body 40 is located on the inner side of the rails being joined. The joint body 40 between rails 20 and 22 could thus be on either of the parallel rails of a section of track.
[0035] In assembling the leveling joint L, the head portions 10 of the rail ends E are brought into contact with each other along their vertical end surfaces 14 . Further, the end portions E are aligned so that the upper surfaces 60 of the head portions 10 are aligned in a common horizontal plane as the leveling joint L is being assembled.
[0036] In an installed leveling joint L, a second joint body 140 is provided to be installed opposite the joint body 40 on right hand joints, such as an inner side of the rails 20 and 22 where the two such rails are of different height. The joint body 140 has like structural components to the joint body 40 , but the relative location of the upper surface 48 and the lower surfaces 50 and 56 of segments 54 and 58 on joint body 140 are reversed from those of joint body 40 . Accordingly, the joint body 140 is used on the inner side of a left hand joint and on the outer side of a right hand joint.
[0037] The leveling joint bodies 40 and 140 which are installed on opposite sides of end sections E of a rail joint according to the present invention are manufactured so that dimensions D 1 and D 2 correspond to the height difference between the taller or newer rail 20 and the shorter or worn rail 22 . The leveling joint bodies 40 and 140 thus have corresponding height dimensions to the difference in height between rails being joined, and the rails R have the same level at their joined end portions E along a level upper surface 60 at their juncture.
[0038] The leveling rail joints according to the present invention achieve increased strength in the assembled structure. The assembled joint bodies in place on the rail ends form a solid unitary structure. This structure functions is achieved as an assembly of several engaged pieces with their aligned contacting surfaces. However, should the need arise one of the structural components of the leveling rail joint can be readily changed in a short time for maintenance or replacement.
[0039] The leveling rail joints in accordance with the present invention enhance the strength of the rail and joint since the matching and engagement of the joint bodies with the corresponding surfaces on the rail ends cause the joint bodies to function in effect as two additional webs to the rail.
[0040] The leveling rail joints of the present invention provide accuracy in the vertical dimensions so that the heads of both rails have the same level at the upper part of the rail heads, making passage of the train wheels relatively noise free and without impact due to a change in height at the rail joint. The leveling rail joints also provide accuracy in the horizontal dimensions so that the connector bolts when installed compress the structural components of the joint with increased strength comparable to that of a solid, unitary piece. The leveling joints according to the present invention in effect provide an additional two web portions in the track structure S in the area of joined rail end portions.
[0041] With the leveling rail joints of the present invention, dips or gaps are not formed between the adjoined end portions of the rails R, so that impact on or movement of rails on passage of wheels is significantly diminished. This in turn affords fewer maintenance needs, safer operation and cost savings.
[0042] Having described the invention above, various modifications of the techniques, procedures, material and equipment will be apparent to those in the art. It is intended that all such variations within the scope and spirit of the appended be embraced thereby. | A joint between connected ends of two rails of different height is provided with a connector/juncture bar member which is configured to fit with and engage corresponding surfaces formed on the rails when the rails are connected together. The joint so formed is one with increased strength, with ease and accuracy of alignment during assembly. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to hopper containers for dispensing viscous liquid or granular materials and, more particularly, to safety door systems for hopper containers as may be used in such applications as pavement construction or repair or in agricultural uses.
2. Description of the Prior Art
Containers that hold and dispense viscous liquid or granular materials for use in pavement construction or repair or agricultural applications are well known in the art. Such containers may be called hopper bodies and be used in stationary or mobile equipment. Some hopper bodies typically include one or more rotating implements in the interior of the hopper for stirring, agitating or facilitating the dispensing of the material from the hopper, usually from an opening disposed in the lower portion of the hopper. For example, hopper bodies used in asphalt pavement repair vehicles are described in U.S. Pat. No. 5,988,935, issued Nov. 23, 1999 and assigned to the assignee of the present invention. This patent is hereby incorporated by reference into this specification in its entirety.
The hopper bodies of asphalt pavement repair vehicles may be large enough to contain up to four cubic yards, or more, of material. The material may be heated to prepare it for use and agitated by a paddle shaft mechanism to maintain a uniform consistency and temperature. Further, during dispensing of the material, an auger used as a screw conveyor may be used to facilitate the dispensing process. Both the paddle shaft and the screw conveyor may be rotating mechanisms powered by hydraulic motors, for example. In some situations of use, the material in the hopper body may become too viscous or tend to clog the rotating mechanisms during a mixing or dispensing operation. In these or similar situations, operating personnel may be tempted to climb inside the hopper body to attempt to clear a blockage or to manually assist the paddle shaft or screw conveyor in stirring or conveying the material. This is an extremely dangerous activity because it exposes the operating personnel to the risk of serious injury by the rotating implements within the hopper body.
What is needed is a system or method for ensuring that operating personnel are prevented from entering the hopper body while the rotating equipment is operating. Further, even if a worker enters the hopper body for some reason, a system or method is needed for stopping the operation of the rotating machinery or any other moving device within the hopper body to minimize the risk of injury to the person.
SUMMARY OF THE INVENTION
Accordingly there is disclosed a safety door system for a hopper body containing a rotating implement powered by a hydraulic control system. The hopper body for transporting liquid or granular material, which has a V-shaped floor to facilitate dispensing the material, further includes the rotating implement for dispensing the liquid or granular materials from an opening in the hopper body and/or for agitating the liquid or granular materials. A safety door, provided for covering and preventing access into the hopper body during use, is hinged along a first edge to a corresponding first side of the hopper body and moveable between a closed and an open position when a hydraulic actuating cylinder, coupled between a second edge of the safety door and a corresponding second side of the hopper body, opens the safety door when the hydraulic actuating cylinder extends its length and closes the door when the hydraulic actuating cylinder retracts its length. An interlock device coupled between the hydraulic actuating cylinder and the hydraulic control system prevents the rotating implement within the hopper body from rotating whenever the safety door is not in its closed position.
In another embodiment there is disclosed a method of limiting access to a hopper body of a mobile pavement repair system during its use, the hopper body having an open top and a V-shaped floor, for transporting liquid or granular materials, and a rotating implement disposed within the hopper body and powered by a hydraulic motor in a hydraulic control system. The method comprises the steps of: covering the open top of the hopper body with a safety door, hinged along a first edge to a corresponding first side of the hopper body and operable between a closed and an open position; opening and closing the safety door using a hydraulic actuating cylinder, the hydraulic actuating cylinder coupling the safety door from a second edge thereof to a corresponding second side of the hopper body, wherein the hydraulic actuating cylinder extends its length to open the safety door and retracts its length to close the safety door; and preventing the rotating implement from rotating, whenever the safety door is not in its closed position, under the control of an interlock device coupled between the hydraulic actuating cylinder and the hydraulic motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a hopper body system for storing and dispensing liquid or granular materials equipped with one embodiment of a safety door system according to the present invention;
FIG. 2A illustrates an end view of the hopper body of the embodiment of FIG. 1 shown with the safety doors in a fully closed position;
FIG. 2B illustrates an end view of the hopper body of the embodiment of FIG. 1 shown with the safety doors in a partially opened position;
FIG. 2C illustrates an end view of the hopper body of the embodiment of FIG. 1 shown with the safety doors in a more fully opened position;
FIG. 3 illustrates a portion of the control apparatus for operating the safety door system of the embodiment of FIG. 1 according to the present invention; and
FIG. 4 illustrates a side cross-sectional view along a vertical centerline of the hopper body of the embodiment of FIG. 1 showing one configuration of rotating implements that may be used in the hopper body.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 , there is illustrated a hopper body system 10 , e.g., for storing and dispensing viscous liquid or granular materials equipped with one embodiment of a safety door system according to the present invention. A hopper body 12 , which includes a powered implement (See, e.g., FIG. 4 ) that rotates or moves in other directions, includes a safety door 14 for covering an open top of the hopper body 12 . The powered or rotating implement may, for example be a conveyor of the belt type or auger type. The hopper body 12 is typically rectangular in shape, may be fabricated of welded steel panels, or other suitable materials considering the materials to be transported or stored. In some applications the hopper body may be round or conform to some other shape. Mobile versions of the hopper body 12 may be adapted for mounting upon the chassis of a truck, or upon a trailer that could be towed by a truck or other vehicle. Stationary versions of the hopper body may be supported on a suitable frame, which typically elevates the hopper body for positioning a mobile unit below the hopper body when dispensing material from the hopper body into the mobile unit.
The safety door 14 shown in FIG. 1 may be fabricated of sheet metal or synthetic materials and configured as a pair of bifold doors as will be described herein below. A first bifold door of the safety door 14 includes first and second door panels 16 , 18 , which are hinged together along the joint 24 . A second bifold door of the safety door 14 includes third and fourth door panels 20 , 22 , which are hinged along the joint 26 . In the illustrative example, the pair of bifold doors ( 16 , 18 and 20 , 22 ), when closed, meet along a junction 32 . The first panel 16 of the first bifold door 16 , 18 is attached along a first edge thereof to a corresponding first side of the hopper 12 via a hinge (not shown) disposed along an axis indicated by a first tie pin 28 . The fourth panel 22 of the second bifold door 20 , 22 is attached along a second edge thereof to a corresponding second side of the hopper 12 via a hinge (not shown) disposed along an axis indicated by a second tie pin 30 . The tie pins 28 , 30 , which are aligned with the hinge axes and protrude from the end of the hopper body 12 , may be provided for securing a tarpaulin or for temporarily suspending lamps or other tools.
Although the illustrated embodiment of the safety door 14 is configured as a pair of bifold door panels, to cover a relatively large hopper body having a width of approximately six feet and a length of, e.g., six to twelve feet, a safety door 14 of the present invention could also be configured as a single panel door, or a pair of half-size door panels, etc., to cover a hopper of smaller dimensions or a different shape, without departing from the principles of the present invention. It is contemplated that different specific applications will suggest, to persons skilled in the art, variations in the door panel configuration and construction that is selected.
In one embodiment, the hopper body 12 may be configured for holding, transporting and dispensing asphalt mix paving materials, as disclosed in U.S. Pat. No. 5,988,935 and assigned to the assignee of the present invention, for repairing pavement damage such as potholes. The hopper body 12 may thus include mechanisms for heating the asphalt mix materials to an appropriate temperature and viscosity and structural features for insulating the walls of the hopper body 12 to retain the heat within the material inside the hopper body 12 . In other applications of a hopper body 12 , e.g., for holding, transporting and dispensing various materials used in road or building construction or agricultural materials for seeding or soil conditioning, the hopper body 12 may be equipped with other apparatus suited to the specific application. In such examples, a safety door system according to the present invention would serve the same purpose—the protection of operating personnel from serious risk of injury during operation or servicing of the hopper body system 10 . Further, as mentioned previously, it is contemplated that the safety door system lends itself as well to stationary as to mobile applications.
Superimposed over the outline drawing of the hopper body 12 in FIG. 1 is a schematic pictorial diagram of the portion of the hydraulic control system 40 involved in the operation of the safety door system of the present invention. Structures of the hydraulic control system 40 in FIG. 1 are not necessarily shown in their actual locations. The double lines in the drawing represent hydraulic fluid (oil) lines and the single lines represent electrical conductors. The hydraulic oil stored in an oil tank 42 is circulated in the direction of the arrows by pump 44 through oil line 48 , a stack valve 58 , an oil return line 50 and the various other lines as will be described. Returning oil, except for oil diverted by the solenoid-operated safety dump valve 110 (which flows along path 54 to return to the oil tank 42 ), is filtered by filter 46 and follows oil return line 50 back to the oil tank 42 . Oil return from the safety dump valve 110 is unfiltered in order to remove any restriction to the flow of oil, which may impair the response of the safety door system to the opening of the safety doors 14 . Control of the flow of oil to various parts of the safety door system is provided by the stack valve 58 .
The stack valve 58 is a system of valves and oil distribution ports, typically configured as a single, composite structure having a plurality of valves and ports, for controlling the flow of oil to operate the various components, including powered implements, connected in the hydraulic system. In the illustrative example the valves are operated by hand levers, coupled to the stack valve 58 by operating rods (not shown) typically moveable between ON and OFF, or FORWARD and REVERSE positions. In some applications the levers may include an intermediate ‘NEUTRAL’ position. In other applications, the levers might be replaced by electric solenoids connected to control rods and operated from a remote position with respect to the device(s) being controlled.
Continuing with FIG. 1 , the stack valve 58 in the illustrated embodiment includes a control lever 60 for operating a screw conveyor motor 70 , a control lever 62 for operating an agitator motor 80 , and a control lever 64 for operating the safety door 14 . The control lever 64 is moveable between a ‘CLOSED’ position, indicated by the letter “C”(Ref. No. 66) and an OPEN position indicated by the letter “O.” The levers 60 , 62 in the illustrated embodiment are operable between FORWARD, NEUTRAL, and REVERSE positions. In some applications the three positions may be LOW, OFF, and HIGH speeds, for example. Hydraulically operated conveyor motor 70 , connected to the stack valve 58 via oil supply line 72 and oil return line 74 , functions to rotate a screw conveyor (auger) in the hopper body. Hydraulically operated (paddle shaft) agitator motor 80 , connected to the stack valve 58 via oil supply line 76 and oil return line 78 , functions to rotate a paddle shaft and thereby control the rotation of the agitating paddles. The screw conveyor and paddle shaft will be described further in the description for FIG. 4 .
Before continuing with FIG. 1 , several other types of hydraulic system components used in the safety door system of the present invention will be described. These components include: an unloader valve ( 92 , 96 , 102 , and 106 ); a check valve ( 94 , 98 , 104 , and 108 ); a normally open dump safety valve ( 110 ); and a proximity switch ( 170 ).
An unloader valve ( 92 , 96 , 102 , and 106 ) is normally open to allow oil to flow through it, if there is any flow at all in the line in which it is installed. In the illustrated embodiment, the unloader valves are installed in bypass lines of a pilot control circuit that is controlled by a dump safety valve 110 . If the dump safety valve 110 opens under a condition in which oil must be diverted from a normal function and returned to the oil supply reservoir (oil tank 42 ), the unloader valve acts to unload the pilot control oil supply circuit to the component being supplied. This action prevents the operation of the component supplied by the protected oil line.
A check valve ( 94 , 98 , 104 , and 108 ) is a one-way poppet valve that allows oil to flow through the oil line in one direction only. The check valve closes if the oil pressure in the line reverses direction. It is used, in the present invention, to maintain oil flow in one direction only—toward the oil tank and away from the pump.
A normally open dump safety valve ( 110 ) is held closed by the action of an energized solenoid coil. When installed in a bypass circuit, a closed dump safety valve prevents the operation of the bypass circuit. When the solenoid drops out, i.e, releases, the dump safety valve opens and allows the oil supply to flow from the unloader valves through the bypass circuit to return to the reservoir.
A proximity switch ( 170 ) is used to sense the change in the proximity of a nearby movable component to a sensing element in the switch. In one configuration of the present invention a set of contacts in the proximity switch, closed when the nearby component is in proximity, open with the loss of proximity. These contacts, when connected in the operating circuit of a solenoid coil in the dump safety valve, cause the solenoid coil to release when the proximity is lost. Release of the solenoid coil opens the dump safety valve, which opens the unloader valves and diverts the oil supply for the conveyor and agitator motors back to the oil tank.
Continuing with FIG. 1 , a bypass circuit (See the enlarged view of the bypass circuit 190 shown in FIG. 3 ) in the hydraulic control system 40 is controlled by a normally open dump safety valve 110 . The bypass circuit includes bypass oil lines that divert the pilot control oil for both the conveyor motor 70 and the agitator motor 80 back to the oil tank 42 whenever the safety door 14 begins to open. The bypass circuit for the conveyor motor 70 includes two branch circuits: a first oil line 82 , an unloader valve 96 connected between the stack valve 58 and a first branch of a tee fitting 90 , which is connected to a first entry branch of the dump safety valve 110 ; and a second oil line 84 , an unloader valve 92 connected between the stack valve 58 and a second branch of a tee fitting 90 , which is connected to the first entry port of the dump safety valve 110 . Similarly, the bypass circuit for the agitator motor 80 includes two branch circuits: a third oil line 86 , an unloader valve 106 connected between the stack valve 58 and a first branch of a tee fitting 100 , which is connected a second entry port of the dump safety valve 110 ; and a fourth oil line 88 , an unloader valve 102 connected between the stack valve 58 and a second branch of a tee fitting 100 , which is connected to the second entry port of the dump safety valve 110 . Persons skilled in the art will realize that not every hydraulic circuit in a machine that may be used in a hopper body will require an associated bypass circuit—only those circuits that may pose a hazard to persons in the proximity thereto or which may require bypass circuits for other operational reasons.
In one embodiment of a stack valve 58 as used in the present invention, the unloader valves 92 , 96 , 102 and 196 are installed in respective auxiliary option ports of the stack valve 58 . Thus, pilot control oil line 84 is associated in the stack valve 58 with oil line 74 and pilot control oil line 82 is associated with oil line 72 . Similarly, pilot control oil line 88 is associated in the stack valve 58 with oil line 78 and pilot control oil line 86 is associated with oil line 76 . Further, an outlet port of the dump safety valve 110 is connected to a return oil line 54 , which returns oil diverted by the dump safety valve 110 to the oil tank 42 . Electric current for operating the solenoid coil 112 of the dump safety valve 110 is connected to the solenoid coil 112 via terminals 114 , 116 , as will be described herein below.
Included in the pictorial schematic of the hydraulic control system 40 in FIG. 1 are hydraulic actuating cylinders and associated components for opening and closing the door panels and providing the safety interlock functions of the door safety system of the present invention. As used in the illustrative embodiment, a hydraulic actuating cylinder is a linear actuator having a sealed tubular cylinder and a movable rod protruding from one end that may be extended from or retracted within the one end of the tubular cylinder. As oil is pumped into one end or the other end of the tubular cylinder, the movable rod, attached to a piston at the end of the rod inside the tubular cylinder, extends or retracts the overall length of the hydraulic actuating cylinder.
A first hydraulic actuating cylinder 120 (which will also be referred to as an ‘actuator 120 ’) is connected between a first pin 122 on the side of an upper portion of the hopper body and a second pin 124 on a first edge of the door panel 22 . As oil is pumped into the actuator 120 it increases in length and causes the door panel 22 to swing upward from the hopper body 12 about the hinge axis 30 . When door panel 22 pivots upward, the door panel 20 , which is hinged to the door panel 22 along the joint 26 , is lifted away from the hopper body 12 . The free edge of the bifold door 20 , 22 slides along the upper rim of the hopper body 12 as it is opened. Similarly, a second hydraulic actuating cylinder 130 (which will also be referred to as an ‘actuator 130 ’) is connected between a third pin 132 on the side of an upper portion of the hopper body and a fourth pin 134 on a first edge of the door panel 16 . As oil is pumped into the actuator 130 it increases in length and causes the door panel 16 to swing upward from the hopper body 12 about the hinge axis 28 . When door panel 16 pivots upward, the door panel 18 , which is hinged to the door panel 16 along the joint 24 , is lifted away from the hopper body 12 . The free edge of the bifold door 16 , 18 slides along the upper rim of the hopper body 12 as it is opened.
The actuators 120 , 130 may be extended together via a common ‘open’ oil line 150 and retracted via a common ‘close’ oil line 160 , both of which are connected at a supply end of the respective oil lines 150 , 160 to the stack valve 58 . The opposite end of the respective oil lines 150 , 160 is connected to respective ‘tee’ fittings 152 , 162 to feed both respective actuators 120 , 130 simultaneously. During an extension cycle, oil flows via oil line 150 , tee fitting 152 where the paths diverge into oil line 154 to port 126 on a base end of the actuator 120 and into oil line 156 to port 136 on a base end of the actuator 130 . The extension cycle is activated by moving the door lever 64 to the ‘OPEN’ position denoted by the letter ‘O’ marked on the stack valve 58 . During a retraction cycle, oil flows via oil line 160 , tee fitting 162 where the paths diverge into oil line 164 to port 128 on the rod end of the actuator 120 and into oil line 166 to port 138 on the rod end of the actuator 130 . The retraction cycle is activated by moving the door lever 64 to the ‘CLOSE’ position denoted by the letter ‘C’ marked on the stack valve 58 . Thus, as oil is pumped into oil line 150 to extend the actuators 120 , 130 the bifold doors 20 , 22 and 16 , 18 are opened. Similarly, as oil is pumped into oil line 160 to retract the actuators 120 , 130 the bifold doors 20 , 22 and 16 , 18 are closed.
Installed near the first end of actuator 120 is a proximity switch 170 , installed in a port in the cylinder body of the actuator 120 . The proximity switch 170 includes a sensing element (not shown)coupled to a pair of normally closed (‘NC’) contacts (not shown). The sensing element, for example, may be a magnet (not shown) within the proximity switch and attached or otherwise coupled to one of the contacts. The rod portion of the actuator is terminated in an iron piston at the inside end of the rod. The magnet responds to the proximity of the piston within the actuator 120 . In the illustrative example, the proximity switch 170 is placed in the port of the actuator so that, when the rod portion is in the fully retracted or ‘rest’ position corresponding to the safety door it controls being in a fully closed condition, the contacts of the proximity switch 170 are held closed by the internal magnet. As the door lever 64 is moved to the OPEN position, the oil pressure in the cylinder portion of the actuator 120 increases and forces the piston and rod to move away from its rest (fully retracted) position. The movement of the piston and rod is sensed by the sensing element in the proximity switch 170 , causing the contacts in the proximity switch 170 to open.
The proximity switch 170 is positioned on the actuator 120 such that the contacts in the proximity switch 170 open when the piston has moved to extend the overall length of the actuator 120 by a predetermined amount, in a typical embodiment of approximately five percent (5%) or less of the overall, extended length of the actuator 120 . This predetermined amount is only an approximation—an initial setting subject to experimentation in the particular case—and may vary substantially with the geometry of the safety door, the hopper body, the actuator used and the tolerances thereof. In the illustrative embodiment, for example, the contacts open when the piston has moved approximately ⅜″ from its rest position. This corresponds with limiting the distance to about one to four inches (e.g., to prevent a person inserting an arm through the door opening) that the safety door is allowed to open before the powered implement(s) is disabled. The overall stroke of the actuator in the illustrative embodiment is 13 inches. In other applications, the location of the port for the proximity switch in the cylinder body of the actuator may be specified to the manufacturer to meet the requirements of a particular application.
It will also be understood that, while the proximity switch is installed in the hydraulic actuating cylinder that opens and closes the safety door in the illustrated embodiment, in other applications a proximity switch may be installed elsewhere. For example, a proximity switch may be installed on the rim of the hopper body (or the edge of a door panel) and configured to respond to a magnet on the edge of a door to be opened (or the rim of the hopper body). In such cases, the contacts in the proximity switch may be adjusted to open when the edge of a door panel and the rim of the hopper body become separated by a distance in the range of, for example, one to four inches. This predetermined distance is approximate and subject to the results of experimentation in the particular application. The determination of this distance may also be in consideration of bending or distortion of the door panel structure. It is understood that the amount the door panel is separated from the hopper body to cause interruption in the movement of the rotating or powered implement is limited to a range of separation, at a location along the periphery of the door panel where a person may most likely attempt to gain entry into the hopper body, that prevents the person, or an arm or leg of the person, from entering the hopper body or reaching into the hopper body to the vicinity of the rotating or powered implement.
The proximity switch 170 has at least two terminals or leads. In the illustrative embodiment proximity switch 170 has a first lead 172 connected to a first terminal 114 of the solenoid coil 112 of the dump safety valve 110 and a second lead 174 connected to a ground terminal 176 . Connected between the terminal 116 of the solenoid coil 112 and the positive terminal 188 of a battery 182 is a wire 184 , an ON/OFF switch 180 and a wire 186 . The battery may be the battery of the vehicle carrying the hopper body 12 , e.g., a 12 VDC battery. Accordingly, the solenoid coil 112 of the dump safety valve 110 would also be rated at the same voltage, 12VDC. Other voltages may be employed, of course, as long as the solenoid voltage rating is consistent with the available supply voltage. A fuse may be inserted in the wire 184 . The ON/OFF switch 180 , which serves to activate the door safety system of the present invention, may be part of a vehicle ignition switch or a stand alone switch. Thus, when the door lever 64 is in a CLOSED position, the safety door is closed, the ON/OFF switch 180 is closed, and the safety door system is activated. If the door lever 64 is moved from the CLOSED position to the OPEN position, the proximity switch senses the movement of the rod in the actuator 120 and opens the circuit of the solenoid 112 of the dump safety valve 110 , diverting the oil supply from the conveyor and agitator motors 70 , 80 to stop the rotation of the rotating implements within the hopper body.
The movement of the bifold doors 16 , 18 and 20 , 22 is illustrated in FIGS. 2A , 2 B and 2 C described herein below, wherein the same reference numbers are used to identify the same structures as shown in FIG. 1 .
Referring to FIG. 2A , there is illustrated an end view of the hopper body 12 with the bifold safety doors 16 , 18 and 20 , 22 of the embodiment of FIG. 1 shown in a fully closed position. In this case, the actuators 120 , 130 are de-energized and in their fully retracted position, the contacts of the proximity switch 170 are closed, the solenoid 112 is energized, and the dump safety valve 110 is also closed. In FIG. 2B , there is illustrated an end view of the hopper body 12 with the bifold safety doors 16 , 18 and 20 , 22 of the embodiment of FIG. 1 shown in a partially opened position corresponding to actuators 120 , 130 having been partially filled with oil. In this case, the actuators 120 , 130 are partially extended, the contacts of the proximity switch 170 are open, the solenoid is de-energized or released, the dump safety valve 110 is open, diverting oil away from the conveyor motor 70 and the agitator motor 80 , which stops the rotating implements. The outline of the rim of the hopper body 12 is shown in a broken line. In FIG. 2C , there is illustrated an end view of the hopper body 12 with the bifold safety doors 16 , 18 and 20 , 22 of the embodiment of FIG. 1 shown in a more fully opened position, with the actuators 120 , 130 nearly fully extended. Here, the conditions of the door safety system are the same as in FIG. 2B .
Referring to FIG. 3 , there is illustrated an enlarged pictorial view of the bypass circuit 190 portion of the hydraulic system 40 for operating the safety door system of the embodiment of FIG. 1 according to the present invention. Most of the structures of FIG. 3 are illustrated in FIG. 1 and like elements bear like reference numbers. FIG. 3 also shows the oil lines 192 , 194 coupling the respective conveyor and agitator bypass circuits to the dump safety valve 110 . A hydraulic flow control valve at port 128 on the actuator 120 is also shown in FIG. 3 . The actual physical location of each of the structures of FIG. 3 , as in FIG. 1 , is not shown; rather, FIG. 3 is intended to show the relationship of the components with each other. For example, the solenoid 112 that controls the safety dump valve 110 may be located remotely to the stack valve 58 or other structures (because it needs only electrical wiring connections and has no oil lines connecting to it), or, it may be part of the stack valve 58 . The latter configuration is preferred because it saves space and provides a neater installation with no increase in cost, in the illustrative application of FIGS. 1 through 4 .
Referring to FIG. 4 , there is illustrated a side cross-sectional view along a vertical centerline of the hopper body 12 of the embodiment of FIG. 1 showing one configuration of powered or rotating implements that may be used in the hopper body. An auger configured as a screw conveyor 196 is supported in bearings 198 , 200 in the end walls of the hopper body 12 and driven by conveyor motor 70 . A paddle shaft configured as an agitator 202 is supported in bearings 204 , 206 in the end walls of the hopper body 12 above the screw conveyor 196 and driven by agitator motor 80 . Included in a lower portion of the hopper body 12 is an outlet opening 208 and a dispensing chute 210 from which viscous liquid or granular material such as an asphalt mix is dispensed from the hopper body by the screw conveyor 196 following agitation as necessary by the paddle shaft 202 during a pothole patching operation. In some embodiments, other powered implements such as conveyor belts, stirring rods, chopping or cutting blades, metering and dispensing apparatus, and the like, which may all be powered by hydraulic motors, may be used within the hopper body 12 .
While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications as described herein above without departing from the spirit thereof. | Accordingly there is disclosed a safety door system, comprising a hopper body containing a powered implement powered by a hydraulic control system, for dispensing liquid or granular materials or for agitating the liquid or granular materials; a safety door for covering and preventing access into the hopper body during use; a hydraulic actuating cylinder operative to open the safety door; and an interlock device coupled between the hydraulic actuating cylinder and the hydraulic control system such that the powered implement within the hopper body is prevented from operating whenever the safety door is not in its closed position.
In another embodiment there is disclosed a method of limiting access to a hopper body of a mobile pavement repair system during its use, the hopper body having a powered implement within the hopper body and powered by a hydraulic motor. The method comprises the steps of covering the open top of the hopper body with a safety door; opening and closing the safety door using a hydraulic actuating cylinder; and preventing the powered implement from operating whenever the safety door is not in its closed position, under the control of an interlock device coupled between the hydraulic actuating cylinder and the hydraulic motor. | 4 |
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to an optical device. It arose in relation to the design of gun sights but could possibly be applicable to other areas of optics. In this specification the terms "optical" and "optics" are to be construed as including visible, infra-red, ultra-violet and any other lens and/or mirror systems.
In operation of a gun sight the gunner sometimes needs to view subjects outside the field of view of the sight and, in order to do so, needs to move the sight so as to change its field of view. This either involves moving the gun, which may be undesirable because such movement can be detected by others; or involves moving the sight relative to the gun. Moving the sight relative to the gun introduces the problem of subsequently needing to re-align the sight with the gun.
SUMMARY OF THE INVENTION
This invention provides an optical device comprising image producing means for producing an image, receiving means for receiving a selected portion of the image, and an adjustment mechanism for adjusting the receiving means so as to select the said portion of the image.
By employing the invention, a gun sight can be built whose objective system (the "observation means") is designed to produce a larger than normal image; i.e. an image of a wider than normal field of view. In such a system the eye-piece is designed to view, at any one time, only a selected portion of the image but can be moved off-axis, to view other selected portions without interfering with the bore-sight of the gun. Furthermore, the gunner is able to adjust the eye-piece so that a feature of particular interest is located at the centre of the "selected portion" allowing it to be viewed with the minimum of aberration.
The objective lens, or other observation means, is preferably designed so that the principal rays are normal to the image surface, thus allowing even focus across the complete field of view of the eye-piece or other observation device. The term "principal ray" is used in this specification in the sense as defined in the book "Modern Optical Engineering" by Warren J. Smith published by McGraw Hill Book Company page 124 i.e. as meaning "the ray through the centre of the aperture stop". The entrance and exit pupils of the system are the images of the aperture stop in object and image space respectively.
The invention is not exclusively applicable to gun sights or to systems using the human eye as a sensor. Instead of the human eye, an optical sensor, e.g. an infra-red detector or array could be employed in which case the eye-piece could be replaced by an analogous optical observation means. There may be other systems in which it is desirable for an infra-red or visual photosensor to view just a part of a larger image and so the invention could find application in environments other than gun sights.
Conventional optical design practices would lead one to believe that by moving the eye-piece or other receiving device off-axis unacceptable aberrations would result. However the inventor has realised that this problem can be overcome by affecting the adjustment in such a way that the optical axis of the receiving device is always colinear with either the optical axis of the observation device or one of its principal rays. It will be understood that, for an optical system such as an eye-piece a change in stop, pupil, position will cause a change in aberrations in the system. By adopting principal rays as axial rays it is possible to move the eye-piece without moving the position of the pupils relative to the eye-piece.
The principle of avoiding unacceptable aberrations by moving one optical system so that its axis remains colinear with the principal rays of another optical system could be useful in other environments. Thus, according to a second aspect of this invention there is provided an optical device comprising first and second optical assemblies, the first optical assembly defining principal rays, and guide means allowing relative movement between the two assemblies in such a way that an optical axis of the second assembly is always co-linear with a principal ray of the first assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
One way in which the invention may be performed will now be described by way of example with reference to the accompanying drawings in which:
the scale figure shows, in very schematic form, a gun fitted with a gun sight constructed in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the scale figure of the drawings there is shown a gun 1 joined by a mechanical or electrical link 2 to a gun sight 3.
The gun sight 3 comprises an objective lens system 4 (forming the "observation means" of the invention). The objective lens system 4 has an optical axis 5 which is bore-sighted to the gun. The characteristics of the optical lens system 4 are as shown by table below.
__________________________________________________________________________SURNUM ND R ND T dN MATERIAL__________________________________________________________________________ 1 1 165.402307 1.5206 8.08495018 8.59E-3 HC 519604NF 1 1.52496NC 1 1.51637 2 1.5206 -164.700937 1 1.22499245 0 AIRNF 1.52496 1NC 1.51637 1 3 1 -150.404756 1.62324 5.38996679 1.705E-2 DF 620364NF 1 1.63208NC 1 1.61503 4 1.62324 -2021.74382 1 82.7255847 0 AIRNF 1.63208 1NC 1.61503 1 5 1 360.312376 1.62324 6.37787572 1.705E-2 DF 620364NF 1 1.63208NC 1 1.61503 6 1.62324 129.129543 1 1.59478431 0 AIRNF 1.63208 1NC 1.61503 1 7 1 168.847528 1.5206 8.58550863 8.59E-3 HC 519604NF 1 1.52496NC 1 1.51637 8 1.5206 -258.145257 1 193.5 0 AIRNF 1.52496 1NC 1.51637 1 9 1 -54.741203 1.70332 2.999415 2.3246E-2 EDF 699301NF 1 1.71546NC 1 1.6922110 1.70332 54.741203 1.57043 13.2477177 9.016E-3 DBC 569631NF 1.71546 1.57498NC 1.69221 1.5659711 1.57043 -30.9588275 1 0.662385886 0 AIRNF 1.57498 1NC 1.56597 112 1 44.6780051 1.51119 7.72541567 7.91E.3 BSC 510644NF 1 1.51518NC 1 1.5072713 1.51119 -64.4225768 1 0.661478509 0 AIRNF 1.51518 1NC 1.50727 114 1 35.0746938 1.57043 13.2477177 9.016E-3 DBC 569631NF 1 1.57498NC 1 1.5659715 1.57043 -26.9805337 1.70332 2.4995125 2.3246E-2 EDF 699301NF 1.57498 1.71546NC 1.56597 1.6922116 1.70332 87.5465713 1.57043 3.4993175 9 016E-3 DBC 569631NF 1.71546 1.57498NC 1.69221 1.5659717 1.57043 ∞ 1 0 0 AIRNF 1.57498 1NC 1.56597 1__________________________________________________________________________ SUR NUM = SURFACE NUMBER FROM LEFT TO RIGHT R = RADIUS OF SURFACE ND = REFRACTIVE INDEX FOR 0.555μ WAVE LENGTH TO LEFT OF SURFACE ND = REFRACTIVE INDEX FOR 0.555μ WAVE LENGTH TO RIGHT OF SURFACE T = THICKNESS/SPACE TO RIGHT OF SURFACE NF = REFRACTIVE INDEX FOR SPECTRAL LINE F NC = REFRACTIVE INDEX FOR SPECTRAL LINE C dN = NF - NC ENTRANCE PUPIL AT FIRST SURFACE
The objective lens system 4 produces an image in an image plane P which is parabaloidal but, in the particular example illustrated, approximates to a spherical surface. In alternative designs the image plane could be plane or could be a distinct parabolic curve. An important feature of the design of the lens system 4 is that it defines principal rays, such as that shown at PR, which pass through the centre C of the entrance pupil (which in this case is the aperture stop defined by the casing 7) and appears to emerge from the virtual exit pupil CA. Each principal ray is normal to the image plane P.
An eye-piece 6 magnifies a portion P1 of the spherical image and presents it to a sensor 8 which, in this case, is a human eye. The gunner thus sees a portion of the field of view which contains a feature on which the gun is targeted. Other features, on which the gun is not currently targeted, can be viewed by adjusting the eye-piece. For this purpose the eye-piece has a flange 6A of part-spherical form which slides in a slot 7A of complimentary shape formed in part of a casing 7 of the gun sight. The arrangement of the flange 6A and slot 7A is such that, at all positions of the eye-piece 6 (e.g. the position indicated in broken lines), the optical axis of the eye-piece is aligned with a principal ray and is normal to the image plane P. Thus the eye-piece is at all times spaced by the same distance from the image plane P.
It is notable that the adjustment of the eye-piece can be affected without interference with the bore-sight of the gun. A graticule might be injected into the system in such a way as to match the spherical image. Alternatively a glass graticule might be used, which could be spherical or plane. Some facility for re-aligning the eye-piece with the axis of the objective might be needed. It would be possible to provide some form of detent mechanism for this purpose.
It will be appreciated that the system as illustrated is very much simplified for the purposes of description and that a practical system would include other features which are matters of routine design practice. For example, an erecting lens or prism system would be required to give an upright image and the system might also be periscopic. In extreme cases one might wish slightly to adjust the aperture stop to redefine the principal rays. In that case, the guiding mechanism for the eye-piece will be designed to take this into account and to ensure that the desired alignment of eye-piece-axis with principal rays is maintained. | In a gun sight an objective lens system 4 is designed to produce a larger than normal image and the eye-piece 6 is designed to be adjusted so as to view different parts of the image. This allows the gunner to view features which are significantly off-axis without interfering with the bore-sighting of the gun. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. Sections 119(a)-(d), 120, 363 and 365 to International Patent Application No. PCT/EP2009/067405, filed Dec. 17, 2009 which designated the United States and at least one other country in addition to the United States and claimed priority to German Application Nos. 10 2008 063 859.5 filed Dec. 19, 2008 and 10 2009 020 385.0 filed May 8, 2009. PCT/EP2009/067405, German Application No. 10 2008 063 859.5 and German Application No. 10 2009 020 385.0 are expressly incorporated by reference herein in their entirety to form a part of the present disclosure.
FIELD OF THE INVENTION
The invention relates to a compressed air tank for utility vehicles
The invention further relates to a method for manufacturing compressed air tanks and to an apparatus for implementing the method.
BACKGROUND OF THE INVENTION
Compressed air tanks for utility vehicles are known from the general state of the art and are used for various functionalities, in particular for supplying compressed air to air suspensions of utility vehicles.
Compressed air tanks can be used in utility vehicles to supply a multiplicity of consuming devices. In addition to compressed-air brake systems and air suspensions, these consuming devices can also take the form, for example, of life-saving systems, (for example airbags) or systems which alter the tire pressure of utility vehicles. Pressure tanks are used, however, not only in the field of utility vehicles and passenger vehicles, but also in respect of other vehicles, for example rail vehicles.
A pressure tank for supplying vehicles, in particular utility vehicles, with a pressurized gaseous medium is known, for example, from DE 20 2005 018 579 U1.
Traditional pressure tanks have a tubular or cylindrical peripheral wall (casing), the open end faces of which are sealed, generally welded, with appropriate caps (outer bases). A cavity for storing the designated gas is thereby formed. The cavity can be loaded and/or unloaded via ports or bores in the casing or in the outer bases.
DE 20 2005 018 579 U1 describes an advantageous embodiment of a compressed air tank such that at least one outer base is configured integrally with the casing. If necessary, both outer bases can also be configured integrally with, respectively, a part of the peripheral wall.
In general terms, compressed air tanks must be able to withstand mechanical loads resulting from internal or external pressure, as well as further mechanical, physical (temperature) and chemical loads. A commonly used material for the manufacture of appropriate pressure tanks is steel. Steel tanks have in essence the advantage of high mechanical strength, and thus high compressive strength, and also good temperature resistance. On the other hand, the chemical resistance of steel with respect to corrosive substances is rather poor. Steel tanks are also relatively susceptible to external weather influences, so that an additional outer and, if necessary, inner coating or paint coating is generally provided. In the prior art, the inner coating of a compressed air tank is obtained by virtue of a so-called wet paint coating, which does not however yield satisfactory results and, in particular, cannot be applied in a cost-effective manner. In the known compressed air tanks, moreover, the problem exists that, at the junction between the outer base and the peripheral wall (casing), a so-called dirt-collecting edge (also termed a chemical edge) is formed. Particles, or in general terms impurities, stick to this edge, which then hinder or prevent the application of an inner coating there. The dirt-collecting edge which is formed when the outer base is connected to the casing can be seen, for example, from FIG. 6 of DE 20 2005 018 579 U1. The outer base has in general an inwardly tapered bead (lead-in chamfer), over which the casing or the peripheral wall is slid. A contact region is thereby created, which is then next welded by a MAG welding process such that the outer base is connected to the casing.
In the compressed air tanks known from the prior art in which both outer bases are configured independently from the casing, two such dirt-collecting edges are consequently formed. Although the embodiment according to FIG. 1 of DE 20 2005 018 579 U1 avoids such dirt-collecting edges, it does however demand a higher cost for the manufacture of the sleeves.
A drawback of the MAG welding process for connecting the outer base to the casing consists in the MAG welding process being relatively slow.
A further problem with the compressed air tanks known from the prior art consists in the fitting of sleeves onto or around the bores in the outer bases or in the casing. The bores serve various purposes, for example the connection of lines. Such connections can be seen, for example, from FIG. 1 of DE 200 23 422 U1, which shows a plastic compressed air tank. In a configuration of a metal pressure tank, it is generally provided to weld sleeves onto the bores in the outer base or the casing. Here, the sleeves are again welded on by a MAG welding process. A drawback with this is that the welding-on of the sleeve engenders a high cost, since the MAG welding process is relatively slow and welding material, moreover, is necessary.
SUMMARY OF THE INVENTION
The object of the present invention is to solve the drawbacks of the prior art, in particular to provide a compressed air tank for utility vehicles which can be manufactured in a cost-effective and simple manner.
The object of the present invention is also to provide an advantageous method for manufacturing a compressed air tank, as well as an apparatus for implementing the method.
By virtue of the fact that the contact surfaces between the casing and outer bases are designed such that the contact surfaces abut squarely or obtusely one against the other and a connection is realized without welding material by laser welding, a compressed air tank without the previously usual dirt-collecting or chemical edge is provided, i.e. the previously present, inwardly tapered protrusion or bead on the outer bases, over which the casing is slid in order to prepare for a weld joint, is dispensed with by the solution provided according to the invention.
The solution according to the invention provides on the inner side of the tank a surface which is optimally suitable for painting and coating, since projections and recesses (dirt-collecting edges or chemical edges) are avoided. A high quality is thereby obtained for the painting or coating. A situation in which residues can collect on the inner edges, which residues, during operation, travel through the lines and possibly cause problems in brake lines or the like, is thereby avoided.
The outer bases can be connected to the casing in a quick and reliable manner by a circumferential weld seam, produced by laser welding. In order to enable the use of a laser, the respective contact surfaces are prepared such that the contact surfaces to be connected can be abutted squarely or obtusely or to size one against the other. The gap which is hereupon formed between the contact surfaces should be as small as possible, i.e. the contact surfaces are precisely worked such that the resulting gap is small, i.e. suitable for laser welding.
For the production of an optimal weld seam, it can be advantageous to align the laser such that the laser beam hits the gap between the two contact surfaces such that no light gap is present.
In one embodiment of the invention, it can be provided that the mutually aligned contact surfaces have a bevel of up to forty five degrees)(45°, preferably fifteen degrees plus or minus five degrees (15°+/−5°). The mutually aligned contact surfaces can here preferably have an identical bevel. The effect of the bevel is that, when the outer base is applied to the end face of the casing, a self-centering of the two components is obtained. The bevel can be configured such that a type of dovetail joint is obtained between the two components to be connected.
The bevel can be configured to both fall and rise from inside to out. In both cases, a self-centering of the components is obtained, at the same time as a light gap is avoided.
The drawback with the bevel consists in the fact that it engenders an additional manufacturing cost. It is therefore preferably provided that the contact surfaces have no bevel, i.e. the contact surfaces run or lie in a radial plane of the compressed air tank or extend in a plane standing perpendicular to the axis of the pressure tank.
It is advantageous if the laser, in addition to the welding of the outer bases to the end faces of the casing, is also used to provide the casing (after bending) with a longitudinal weld seam.
It is advantageous if two laser heads are used to produce the orbital weld seam for connecting an outer base to the casing, which laser heads simultaneously weld the contact surface between the outer base and the casing. A further speed advantage is thereby obtained.
All weld joints for the manufacture of the compressed air tank, i.e. the longitudinal weld seam and the two orbital weld seams, for example, can be produced by means of the laser without welding material. One advantage is that in this case no oxide layer is formed, since the component is only lukewarm.
According to the invention it is further provided that the sleeve is welded onto the bore by laser welding or by CD welding.
This enables the sleeve to be welded on substantially more quickly than in the prior art. An addition of welding material is no longer necessary.
A further advantage of laser welding consists in the fact that the visually unattractive weld seam bead which is regularly formed in MAG welding is avoided. In laser welding, moreover, no cleaning of the weld seam is necessary, so that this operation, which is frequently necessary in the case of a MAG weld seam, can be dispensed with.
Compressed air tanks generally have a plurality of sleeved bores, which bores are arranged both in one or both outer bases and/or on the casing. It is here advantageous if the inner diameter of the bore is somewhat larger than the inner diameter of the sleeve. The sleeve can be configured in a known manner, preferably with an internal thread. The sleeve is preferably made of steel or special steel.
The bores or holes in the outer base can be produced, for example, by piercing dies or by punches.
It is advantageous if the laser welds the sleeve to the compressed air tank circumferentially, radially on the outside.
In one embodiment, it can be provided that the sleeve has an indentation, a chamfer, a (preferably wedge-shaped) groove or the like, which is arranged such that between this and the compressed air tank there remains a burr formed by the sleeve, an annular projection or the like. It can here be provided that the laser beam of a laser applied from outside penetrates into the indentation, the chamfer or the groove such that the burr or the annular projection of the sleeve is welded to the adjacent material of the compressed air tank. The sleeve is thereby able to be welded to the compressed air tank in a particularly reliable, quick and robust manner. It is additionally advantageous if the welding of the sleeve to the compressed air tank is realized radially on the outside and circumferentially on the bottom side of the sleeve. Hence no gap, into which impurities might possibly penetrate, is present between the sleeve and the compressed air tank.
The welding of the sleeve by a laser applied on the outside is suitable both for welding of the sleeve on the outer bases and on the casing.
Alternatively or in addition thereto, it can also be provided that the laser, in particular in order to weld sleeves onto bores of the outer base, is applied from inside. Preferably, the laser can here weld an annular surface of the sleeve to the compressed air tank, which annular surface lies radially as far out as possible. Hence, a radially circumferential gap between the sleeve and the compressed air tank is once again avoided.
The fusion edge should preferably lie radially as far out as possible.
One advantage of the sleeve being welded on by the laser being applied to the inner side of an outer base consists in the fact that the sleeve fuses particularly advantageously with the material of the compressed air tank. The welding process, as the inventor has discovered, can here be managed in a particularly reliable manner. The process is particularly suitable for fitting sleeves to the outer base, since in this case the laser can be applied particularly easily to the inner side of the outer base. The sleeves can here preferably be welded onto the outer base before the outer base is welded to the casing, since the laser cannot be used to weld in the casing.
A further option for welding the sleeve onto or around the bore of the compressed air tank consists in using a so-called CD welding process. CD welding process means Capacitor Delivery welding. CD welding is a special form of projection welding and, as the inventors have discovered, has particular advantages in the connection of sleeves to compressed air tanks. Through an appropriate earthing of the compressed air tank, a permanent and reliable welding of the sleeve at the designated location on the compressed air tank can be realized, followinglication of the sleeve, within just a few milliseconds by an appropriate burst of current. The sleeve can be applied, for example by means of a copper die, at the designated location on the compressed air tank. The sleeve is then welded onto the compressed air tank by the use of a suitable burst of current. A particular advantage consists in the fact that, by using an appropriate number of copper dies, it is possible to weld a plurality of sleeves simultaneously in a single operation.
In a particularly advantageous refinement of the invention, it can be provided that the sleeve has on its bottom side adjoining the compressed air tank at least one fusion edge, which is connected to the compressed air tank by CD welding. The connection of the sleeve to the compressed air tank is thus realized not by areal welding, but simply by welding of the (preferably annularly) circumferential fusion edge to the adjacent material of the compressed air tank. In this context, the inventor has recognized that an areal welding of the sleeve is disadvantageous compared to the configuration of a fusion edge on the bottom side of the sleeve. It is advantageous if the fusion edge annularly encircles the bottom side of the sleeve radially on the outside (as far out as possible). A radially circumferential gap between the top side of the compressed air tank and the bottom side of the sleeve is thereby avoided. If necessary, a plurality of circumferential fusion edges can be formed or a plurality of fusion points or fusion lines can be present on the bottom side of the sleeve. The welding of the sleeve on the compressed air tank is thereby further improved, though the fusion edges add to the cost of manufacture of the sleeve.
It is advantageous if two annularly circumferential fusion edges are formed. In this case, one fusion edge can be configured such that it encircles the bottom side of the sleeve radially on the outside, and the other one such that it encircles it radially on the inside. This avoids a situation in which dirt or impurities can penetrate beneath the sleeve. If necessary, a plurality of, for example, five circumferential fusion edges may also be provided.
It is advantageous if an apparatus for conducting the CD welding process is provided, which apparatus has dies which resiliently bias the sleeve against the compressed air tank in order to ensure that the sleeve, when current is applied, is pressed against the compressed air tank. The welding process is thereby further improved. Preferably, the springs press against the sleeve with a slight pretension.
It is particularly advantageous if the sleeve has a form which enables the sleeve to be inserted, at least with a section, into the bore. Preferably, the sleeve can here be inserted into the bore in the casing or in one of the outer bases of the compressed air tank to the point, where the bottom side of the sleeve lies substantially in one plane with the adjoining inner side of the compressed air tank. Dirt-collecting and chemical edges are thereby avoided. The insertion of the sleeve into the bore can be enabled, for example, by the sleeve having an outer diameter which is slightly smaller than the inner diameter of the bore. If necessary, a press fit can also be provided. Alternatively, it can also be provided that the sleeve has a projection, a boss, a taper or a step which is inserted into the bore. The sleeve can here have in total an outer diameter which is larger than the inner diameter of the bore, so that the sleeve can be mounted from outside onto the bore and only the taper or the projection of the sleeve juts into the bore. The sleeve can thus rest substantially flat upon the outer side of the compressed air tank and be welded to the tank from outside.
Irrespective of whether the sleeve is welded by means of laser or CD welding, it has proved advantageous if that region of the casing and/or of the outer bases which surrounds the bore is flat or flattened. The casing, but also the outer bases, generally have a curvature. Hitherto, this has been tolerated and appropriately compensated by the application of filler wire. The inventor has recognized, however, that the welding of the sleeve is able to be considerably improved if the region onto which the sleeve is to be welded has no curvature. A flattening can be produced particularly advantageously by a stamping tool.
According to the invention, it is provided that the inner coating of the tank is produced by a powder coating. In the previously known pressure tanks, the coating is applied by a wet coating process (wet painting). This appeared necessary, since, because of the projections and edges on the inner side of the tank, it was felt that only a wet coating process could ensure a complete inner coating. Now that, according to the invention, dirt-collecting edges and the like on the inner side of the tank are avoided, the advantages of a powder coating process can be exploited.
In this context, it is advantageous if the powder coating is applied electrostatically to the inner side of the tank, preferably by a tribo charge. The inventor has recognized that though the use of a powder coating process is particularly suitable, it can pose problems in terms of the realization. A powder coating of the casing and of the outer base before these are welded together has proved less suitable. More advantageously, the powder coating should only be applied once the casing and the outer bases are welded together. In this case, the problem arises itself that the powder has to be introduced into the pressure tank. Furthermore, it is necessary to ensure that the powder sticks there to the inner side of the tank such that a full and reliable coating is achieved. The inventor has here recognized that this is best achieved by an electrostatic powder coating process and, particularly preferably, by the use of a tribo charge. By an electrostatic powder coating process is understood, in general terms, both a corona charge and a tribo charge. The corona charge is a high-voltage process. In the case of the tribo charge, the powder particles are driven at high speed along the surface, whereby they are charged. For the introduction of the powder into the compressed air tank, a tribo lance can be used. Preferably, a sleeve opening or one of the bores in the compressed air tank, preferably one of the bores in the outer base of the compressed air tank, can here be used as the access opening. By means of a nozzle or a spray head on the tip of the tribo lance, the powder which has been charged by the friction can be sprayed into the interior of the pressure tank. Due to the charge, the powder attaches to the inner side of the compressed air tank.
The process of the electrostatic charging and the attachment to the inner wall is fundamentally known. The inventor has recognized that, with the compressed air tank, an optimal, reliable and even powder distribution in the interior of the compressed air tank is obtained. This, in particular, since the geometry in the interior of the compressed air tank, according to the invention, has been created such that projections and recesses are no longer present.
According to the invention, it can be provided that the tribo lance is first driven sufficiently far into the compressed air tank that that end of the compressed air tank which is remote from the access opening can be provided with a coat of powder. As the powder is being sprayed out, the tribo lance can then be withdrawn, so that an even distribution of the powder is ensured.
The inner coating can next be dried at a temperature of one hundred fifty degrees Celsius to two hundred fifty degrees Celsius (150° C. to 250° C.), preferably two hundred degrees Celsius plus or minus ten degrees Celsius (200° C.+/−10° C.)
In the method according to the invention for manufacturing a compressed air tank for utility vehicles, it is firstly provided that a cylindrical or tubular casing is bent out of a sheet blank. It is further provided that two outer bases are produced by drawing or stamping and are welded to the end faces of the casing. Preferably prior to being welded together, at least one outer base and/or the casing are provided with a bore, onto which a sleeve is welded. The sleeve can here likewise already be welded on before the casing is put together with the outer bases, but also afterward. It is provided that at least the inner side of the compressed air tank is provided with an inner coating. According to the invention, it is here provided that the inner coating is produced by a powder coating. It is further provided according to the invention that the contact surfaces between the casing and the outer bases are designed such that the contact surfaces can be abutted squarely or obtusely one against the other, whereafter the contact surfaces are joined together by laser welding without welding material. According to the invention, it is further provided that the sleeve is applied to the bores by laser welding or by CD welding.
A particularly preferred apparatus for conducting the process with regard to the production of a powder coating on the inner side of the compressed air tank is obtained from an apparatus having a lance, preferably a tribo lance having a spray head for insertion into the compressed air tank. In addition, the apparatus should have a bolt having an inner bore for insertion into a bore in the outer base in order to produce an access opening for the lance. In addition, a beam should be provided, in order to receive the compressed air tank such that the access opening is aligned downward. Furthermore, a device should be provided, in order to introduce the lance through the access opening and withdraw it again in the course of delivery of the coating powder.
It has proved advantageous if that part of the lance which is to be introduced into the bolt, as well as the spray head, have a diameter of no more than twenty millimeters (20 mm), preferably of no more than fifteen millimeters (15 mm). The lance with the spray head is thereby able to be inserted through the inner bore of the bolt into the compressed air tank particularly easily.
It is advantageous if the apparatus has a device for pretreating the inner side of the compressed air tank. The pretreatment can here consist in cleaning the inner side of the compressed air tank, for example in degreasing it, washing it and clearing it of chemicals. The following coating process is thereby improved.
The tribo lance can consist, for example, of a plastic, preferably of polyamide or polyethylene. Preferably, the beam is configured such that a plurality of compressed air tanks can be fitted, for example twelve compressed air tanks. It can here be advantageous if a corresponding number of tribo lances and bolts is provided.
It is advantageous if the compressed air tank is first fixed on the beam. After this, the bolt, which is provided with an inner bore, can be inserted into the access opening. The bolt can here preferably have a lead-in aid, for example a funnel, through which the lance can be inserted.
The apparatus can have a device for drying the applied powder, the device preferably being designed such that the drying takes place at a temperature of one hundred fifty degrees Celsius to two hundred fifty degrees Celsius (150° C. to 250° C.), preferably two hundred degrees Celsius plus or minus ten degrees Celsius (200° C.+/−10° C.). This drying process is fundamentally known from the prior art.
The tribo lance can also be made of Teflon or have Teflon. The spray head is preferably configured such that it sprays in all directions, i.e. both radially and to the front and rear.
The compressed air tank according to the invention is suitable for any chosen gases.
The compressed air tank can, if necessary, have an outer base configured integrally with the casing, as is represented in FIG. 6 of DE 20 2005 018 579 U1.
BRIEF DESCRIPTION OF THE DRAWINGS
Illustrative embodiments of the invention are represented schematically below with reference to the drawings, wherein:
FIG. 1 shows a perspective representation of a compressed air tank;
FIG. 2 shows a longitudinal section through a compressed air tank;
FIG. 3 shows a top view of an outer base of a compressed air tank;
FIG. 4 a shows an enlarged longitudinal section through a selected portion of a compressed air tank according to the detail IV of FIG. 2 , in the region of the plane of contact between the contact surfaces of an outer base and of the casing, with oblique-running contact surfaces;
FIG. 4 b shows an enlarged longitudinal section through a selected portion of a compressed air tank according to the detail IV of FIG. 2 , in the region of the plane of contact between the contact surfaces of an outer base and of the casing, with straight-running contact surfaces;
FIG. 5 shows a sectional representation of that region of an outer base in which a sleeve is welded onto a bore;
FIG. 6 shows a particularly suitable design of a sleeve for welding the latter to the compressed air tank by means of a laser;
FIGS. 7 a to 7 c show three further suitable designs of a sleeve for welding the latter to the compressed air tank by means of a laser applied to the outside;
FIG. 8 shows a view of an inner side of an outer base to which a sleeve is applied on the outside, which sleeve is welded to the outer base by a laser applied to the inner side.
FIG. 9 shows a view of a bottom side of a sleeve having a fusion edge for the use of a CD welding process;
FIG. 10 shows a longitudinal section through a compressed air tank with a schematic representation of a tribo lance inserted into the compressed air tank;
FIG. 11 shows an advantageous apparatus for the inner coating of a pressure tank in a schematic representation.
DETAILED DESCRIPTION
Compressed air tanks for utility vehicles are sufficiently known from the general state of the art, for which reason their basic working method and their integration into a utility vehicle are not examined in detail below. Reference is simply made to DE 20 2005 018 579 U1 and to DE 200 23 422 U1.
The compressed air tank 1 according to the invention is suitable for absorbing high pressures, of over 70 bar for example.
FIGS. 1 and 2 show a compressed air tank 1 for utility vehicles which is formed of a tubular or cylindrical casing 2 and two outer bases 3 . The casing 2 can be produced, for example, from a correspondingly large sheet blank by bending. The outer bases can be produced in a fundamentally known manner by drawing or by stamping.
In the illustrative embodiment, the outer bases 3 are of saucer-shaped configuration or have a depression.
As the material for the casing 2 and the outer bases 3 , various materials are suitable, in the illustrative embodiment it is provided that the casing 2 and the outer bases 3 are formed of metal, preferably steel or special steel, or alloys thereof. In principle, compressed air tanks 1 can also be formed of aluminum or aluminum alloys.
In the illustrative embodiment, the compressed air tanks 1 have a length between two hundred millimeters (200 mm) and fourteen hundred millimeters (1400 mm). It has proved advantageous to configure the shortest tank with a length of two hundred millimeters (200 mm) to three hundred millimeters (300 mm) and the longest tank with a length of thirteen hundred millimeters (1300 mm) to fourteen hundred millimeters (1400 mm).
As is evident from FIGS. 1 to 3 , the compressed air tank 1 has bores 4 both in the casing 2 and in one of the outer bases 3 , which bores can be used for the connection of various lines, for example to the consuming devices or for the drainage of condensation water. The bores 4 are respectively provided with a sleeve 5 , which in the lead-out region can be provided with an internal thread to enable the simple connection of ongoing lines. The inner side 1 a of the compressed air tank 1 is provided with an inner coating 6 , the application of which is not represented in detail in FIGS. 10 and 11 .
As is evident in particular from FIGS. 1 through 4 a and 4 b , the casing 2 has contact surfaces 2 a and the outer bases 3 have contact surfaces 3 a , which are designed such that the contact surfaces 2 a , 3 a abut (squarely or obtusely) one against the other. The casing 2 and the outer bases 3 can be welded together at the contact surfaces 2 a , 3 a without welding material by laser welding. A laser 7 which is used for this purpose is represented schematically in FIG. 4 . In the illustrative embodiment, it is provided that the laser 7 has two laser heads, which simultaneously weld together the contact surfaces 2 a , 3 a between an outer base 3 and the casing 2 . Alternatively, two or more lasers may also, of course, be used.
It has proved advantageous if the casing 2 has a material thickness of two point two millimeters plus or minus zero point five millimeters (2.2 mm+/−0.5 mm).
FIG. 4 a shows contact surfaces 2 a , 3 a which are inclined in relation to a radially extended plane of the compressed air tank 1 or have an angle to the radial. A bevel 8 is thereby formed, which bevel can measure up to 45°, preferably 15°. This gives a self-centering of the outer base 3 relative to the casing 2 .
For the production of the bevel 8 , in the illustrative embodiment it is provided to stamp the edges of the casing 2 or of the outer bases 3 .
FIG. 4 b shows an alternative embodiment to FIG. 4 a of the contact surfaces 2 a , 3 a , which are not inclined in relation to a radially extending plane of the compressed air tank 1 or run in the plane. The contact surfaces 2 a , 3 a thus abut one against the other in a straight or flat arrangement, i.e. without inclination one to the other. This embodiment is preferable to the embodiment represented in FIG. 4 a.
The bores 4 in the casing 2 and the outer base 3 can preferably be formed by punching. It is here provided that the bores 4 or the holes are punched from inside to out. Next, the region around the bore 4 can be provided by means of a stamping die (in a non-detailed manner) with a flattening 9 . The flattening 9 is represented schematically in FIG. 3 . In the illustrative embodiment, a flattening 9 is provided at all bores 4 .
The sleeve 5 can be applied onto the bore 4 on the outside and welded to the adjacent material of the compressed air tank 1 . In the illustrative embodiment according to FIGS. 5 to 9 , it is provided that the inner diameter of the bore is larger than the inner diameter of the sleeve 5 .
In the illustrative embodiment, the welding of the sleeves 5 on the compressed air tank 1 is realized by laser welding or by CD welding.
In the illustrative embodiment, the sleeve 5 is made of metal, preferably of steel or special steel.
According to FIG. 5 , it is provided that the sleeve 5 has a substantially uniform outer circumference. If necessary, it can be provided that the end-face edges are slightly chamfered. According to FIG. 5 , it is here provided that the laser 7 is applied from outside, i.e. to the outer side of the outer base or of the casing 2 . The laser 7 is intended to weld the sleeve 5 to the adjacent material of the compressed air tank 1 as far out as possible in the radial direction and in annularly circumferential configuration. An advantageous positioning of a weld seam 10 produced by the laser 7 is represented schematically in FIG. 5 .
FIG. 6 shows a particularly suitable form of the sleeve 5 for conducting the laser welding process described according to FIG. 5 . The sleeve 5 here has an indentation 11 or groove, which is arranged in the peripheral wall of the sleeve 5 such that a burr 12 formed by the sleeve 5 , or an annular projection, remains between the indentation 11 or groove and the outer side of the compressed air tank 1 . The laser beam of the laser 7 applied from outside penetrates preferably into the indentation 11 or groove in order to fuse or weld the burr 12 or the annular projection of the sleeve 5 to the adjacent material of the compressed air tank 1 . A preferably provided positioning of the resulting weld seam 10 is represented by dashed lines in FIG. 6 . The indentation can also have a wedge-shaped course, so that beneath the wedge-shaped groove there remains a burr or an annular projection for welding to the underlying material of the compressed air tank. Alternatively thereto, the bottom side of the sleeve 5 may also be provided circumferentially with a chamfer.
FIGS. 7 a to 7 c show three particularly suitable forms of sleeves. FIGS. 7 a to 7 c also show a particularly suitable solution for welding the sleeve 5 to the compressed air tank 1 .
As is evident from FIGS. 7 a to 7 c , in the preferred embodiment of the sleeve 5 it is provided that this has an outer diameter which is smaller than the inner diameter of the bore 4 . The sleeve 5 can hence be introduced or inserted into the bore 4 , at least with a section of its axial length, and is welded there.
FIG. 7 a shows an embodiment in which the sleeve 5 has an outer diameter which is substantially constant over its axial length. The sleeve 5 is here inserted with an end-face end into the bore 4 and welded there. Preferably, the sleeve 5 can be inserted into the bore 4 to the point where the bottom side of the sleeve 5 , which bottom side is inserted into the bore 4 , is substantially flush with the inner side of the outer base 3 or of the casing 2 .
The welding of the sleeve 5 according to FIG. 7 a can be realized by a laser 7 applied on the outer side and/or inner side. In FIG. 7 a , an externally applied weld seam 10 is represented.
The advantage of the solution represented in FIG. 7 a consists in the fact that the sleeve 5 can be produced in a particularly cost-effective manner, preferably as a turned part.
According to the embodiment represented in FIGS. 7 b and 7 c , it is provided that the sleeve 5 has on its bottom side facing the bore 4 a taper 13 and/or an axially prominent projection and/or a boss. The taper 13 and/or the projection and/or the boss here have, at least at their end facing away from the sleeve 5 , an outer diameter which is smaller than the inner diameter of the bore 4 . The sleeve 5 can thus be inserted with its taper 13 or the projection or boss into the bore 4 , as is represented in FIGS. 7 b and 7 c.
According to the embodiment represented in FIGS. 7 b and 7 c , it can be provided that the taper 13 or the projection or boss is integral with the sleeve 5 . As is also evident from FIGS. 7 b and 7 c , the course of the outer diameter of the taper 13 or projection or boss is preferably tailored to the course of the inner edge of the bore 4 . The taper 13 is thereby able to be inserted particularly easily into the bore 4 . It is further ensured that, in the laser welding, no light gap is present.
As is evident from FIGS. 7 b and 7 c , the taper or the projection or boss has an outer diameter which at least approximately completely fills the bore 4 . In both embodiments, the weld seam 10 can be formed from the inside and/or from the outside. In FIGS. 7 b and 7 c , a weld seam 10 is formed from the outside by means of laser welding. This embodiment is preferable.
As is evident from FIG. 7 b , the sleeve has in this embodiment a taper 13 or a projection or boss with an oblique course. The taper 13 or the projection or boss has a chamfered outer edge, so that the outer diameter of the taper 13 or projection or boss tapers toward the free end thereof. The angle α of the chamfer can here measure, for example, thirty degrees (30°) to seventy degrees (70°), preferably sixty degrees (60°). As a result of the chamfer, a self-centering is obtained.
FIG. 7 c shows a particularly preferable embodiment of the sleeve 5 . It is here provided that the taper 13 , projection or boss is configured as a step of substantially constant outer diameter. The sleeve 5 can here be produced as a turned part. It is hence unnecessary to produce the bore 4 in the outer base 3 or in the casing 2 with a chamfer. Alternatively, a chamfer can additionally be provided, however, in the outer base.
As a result of the relinquishment of the chamfer in the outer base 3 or in the casing 2 , the bore 4 can be produced in a particularly simple and cost-effective manner by punching.
According to the embodiment represented in FIG. 7 b and that represented in FIG. 7 c , it can be provided that the bottom side of the taper 13 runs substantially in one plane with the inner side of the outer base 3 or of the casing 2 in the region of the bore 4 .
The advantage of the embodiments represented in FIGS. 7 a to 7 c over the embodiments according to FIGS. 5 and 6 consists in the fact that no dirt-collecting edge is formed within the compressed air tank 1 , since, as a result of the form and arrangement of the sleeve 5 , recesses on the inner side of the compressed air tank 1 are avoided.
In principle, the illustrative embodiments represented in FIGS. 7 a to 7 c can be combined with the further features which have been represented with respect to the other embodiments or generally with respect to the invention.
FIG. 8 shows schematically an alternative welding of the sleeve 5 to the compressed air tank 1 . It is here provided that the laser 7 is applied to the inner side of an outer base 3 . The sleeve 5 mounted on the outside of the compressed air tank 1 is thus welded on the bore 4 by action of the laser 7 upon the inner side of the outer base 3 . Preferably, the laser 7 is applied such that it welds a radially outer annular surface of the sleeve 5 to the adjacent material of the compressed air tank 1 . The radially outer annular surface is represented by dashed lines in FIG. 8 . Since the inner diameter of the sleeve 5 is smaller than the inner diameter of the bore 4 , the inner edge of the sleeve 5 overlaps the inner edge of the bore 4 . According to the invention, it can also be provided that the laser welds not just one annular surface of the sleeve 5 to the adjacent material of the compressed air tank, but two or more.
FIG. 9 shows a further option for welding the sleeve 5 onto the bore 4 or onto the compressed air tank 1 . For this, a CD welding process is used. The sleeve 5 is applied at the designated location on the compressed air tank 1 and is welded to the adjacent material of the compressed air tank 1 by a short burst of current or by the use of the CD welding process. As is evident from FIG. 9 , the sleeve 5 has on its bottom side 5 a a circumferential fusion edge 14 . The fusion edge 14 here has an annular course. The fusion edge 14 is connected or fused to the compressed air tank by the CD welding process. Preferably, the fusion edge 14 has a wedge-shaped course, i.e. tapers starting from the bottom side 5 a of the sleeve 5 , in the direction of the compressed air tank 1 . If necessary, two or more fusion edges 14 can also be configured on the bottom side 5 a of the sleeve 5 . It is advantageous if the fusion edge 14 annularly encircles the bottom side 5 a of the sleeve 5 radially on the outside.
The compressed air tank 1 which is represented in the illustrative embodiment has an inner coating 6 on the inner side 1 a of the compressed air tank, which is produced by a powder coating process. In the illustrative embodiment, it is here provided that the powder coating is applied electrostatically to the inner side 1 a of the compressed air tank and, for this purpose, a tribo charge is used. As is evident from FIG. 10 , in the illustrative embodiment it is provided that the powder coating is introduced into the compressed air tank 1 by a tribo lance 15 . The tribo lance 15 here has a spray head 16 , which delivers powder both radially and to front and rear. This is represented correspondingly in FIG. 10 .
A particularly suitable apparatus for conducting the powder coating is represented in FIG. 11 . Here a beam 17 is provided to receive a plurality of compressed air tanks 1 . For each compressed air tank 1 , a tribo lance 15 having a spray head 16 is here provided. In addition, a bolt 18 having an inner bore is provided. The bolt 18 is inserted into a bore 4 in the outer base 3 in order thus to provide an access opening for the lance 15 . That part of the tribo lance 15 which is to be introduced into the bolt 18 , as well as the spray head 16 , are preferably intended to have an outer diameter of no more than twenty millimeters (20 mm), particularly preferably no more than fifteen millimeters (15 mm). The apparatus represented in FIG. 11 also has a device 19 for introducing the tribo lances 15 through the access opening and for withdrawing them again as the coating powder is delivered. According to FIG. 11 , a device 20 for pretreating the inner side 1 a of the compressed air tank 1 is further provided. In addition, a device 21 for drying the applied powder at a temperature of 150° C. to 250° C., preferably 200° C., is provided. The beam 17 can be movable by an appropriate suspension mounting. The beam 17 fixes the compressed air tank 1 both at the top and at the bottom. It is provided that a plurality of compressed air tanks 1 are treated simultaneously.
In the illustrative embodiment, it is provided that also the outer side of the compressed air tank 1 is provided with a powder coating.
While the foregoing constitute preferred embodiments of the invention according to the best mode presently contemplated by the inventor of making and carrying out the invention, it is to be understood that the invention is not limited to the particulars described above. In light of the present disclosure, various alternative embodiments and modifications will be apparent to those skilled in the art. Accordingly, it is to be recognized that changes can be made without departing from the scope of the invention has particularly pointed out and distinctly claimed in the appended claims as properly construed to include all legal equivalents. | The invention relates to a compressed air tank for utility vehicles, comprising a tubular or cylindrical jacket sealed at both ends by way of welded outer bases. At least one outer base and/or the jacket is provided with a hole. A sleeve is welded onto the hole. At least the inside of the compressed air tank is provided with an inner coating. The contact surfaces between the jacket and the outer bases are adapted such that the contact surfaces abut one another and such that the contact surfaces can be welded together without using any weld material through laser welding. The sleeve is welded onto the hole by way of laser welding or CD welding. The inner coating of the tank is manufactured by powder coating. | 8 |
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application No. 60/294,536 filed May 30, 2001 and which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed towards a laboratory device that facilitates studies using cell culture techniques to assay biomaterials. Specifically this invention is a device that facilitates control of the exposure of animal cells and/or media to biomaterials and the measure of the main and interaction effects of the cells, tissue and media on the biomaterials. By way of example, but not as a limitation, the device can be used to evaluate biomaterial toxicity or drug release from films. The laboratory device also facilitates the recovery of biomaterials, cells, tissues, and/or the cell-material interface following controlled experiments.
2. Background
Technology related to the continued development of medical devices for humans comprises two fundamental areas of research and development: design and fabrication of said devices and development of minimally toxic, biologically compatible materials (biomaterials) to be used in the manufacture of said medical devices. Safety and health considerations require that the potential of toxic effects of biomaterials that are otherwise suitable for medical devices must be fully evaluated, and performance considerations require that the material maintain its function in an in vivo environment. Devices to facilitate cell culture and study are known in the art as shown and claimed in U.S. Pat. Nos. 5,578,492 and 5,139,951, which are hereby incorporated by reference in their entirety.
Direct contact cell culture is employed to evaluate biomaterial reactions and interaction of cells with a biomaterial. Evaluation includes toxicity, drug delivery, or material degradation analysis. Such studies require a laboratory apparatus that supports cellular growth, allows cell cultures to be exposed to known amounts of biomaterials, and to be handled for study purposes which includes observation of cells, sampling materials and media, changing media, and moving samples into and out of controlled environment facilities while protecting samples from contamination. Additionally, such evaluation apparatuses must provide a container which provides surfaces to support cellular growth.
Details of the preparation of media and methods of culture of cells are well known and comprehended by those skilled in the art. Specific environmental conditions including factors such as minimizing contamination of cultures and maintaining controlled temperature, humidity, and light conditions are common to all studies although specific conditions of light, temperature, and humidity may vary with the material to be tested. Nonetheless, the specific conditions are well known to those skilled in the art or are otherwise readily available without the need for excessive experimentation. See for example, R. I. Freshney, “Culture of Animal Cells”, 2 nd ed., Wiley/Liss, 1994, N.Y., N.Y., which is hereby incorporated by reference in its entirety.
With current technology, biomaterials may float or otherwise move during the study making precise observations more difficult. To minimize these issues, materials are commonly glued or weighted, which introduces additional complications. Additionally, current technology necessitates mechanical collection using a spatula or similar instrument to recover the cells from bioassay apparatus. Commonly, this results in damage to the cells thereby reducing the value of the cells for further analysis. These and related difficulties limit aspects of the accuracy and dependability of biomaterial assays. Accordingly, there remains room for variation and improvement in the art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a biomaterial assay apparatus and process which provides a stable, controlled surface for cell growth and study. Further the apparatus and process may expose the cells to only a single surface of the biomaterial. The fixed positioning of the biomaterial being evaluated minimizes damages to cell material and resultant experimental error. In addition, the apparatus is readily manufactured using injection-molding techniques as would be recognized by one skilled in the art.
This and other objects of the invention are accomplished by a well-plate insert comprising a support platform and at least one cylinder that traverses and is connected to the platform. A portion of the cylinder extends below the platform and fits into a well of a multi-well plate. The distal end of the extended portion of the cylinder contacts the floor of the well and is capable of forming a fluid-tight seal with a biomaterial placed on the floor. The well-plate is positioned in a frame connected to the platform of the sleeve insert. The connection can be adjusted to increase a compressible force between the interface of the cylinder and biomaterial, thereby creating the potential for a fluid-tight seal between the biomaterial and cylinder and simultaneously preventing excessive movement of the biomaterial to be assayed. In this configuration, only a specified portion of the biomaterial is exposed to cell growth, and cells are protected from damage.
Further, the invention includes a process for the assay of biomaterial, for using the growth of animal cells on the biomaterial as a bio-indicator of toxicity of the biomaterial. The process requires providing a container suitable for cell culture and placing a substantially flat sample of biomaterial on the floor of the container, followed by inserting a hollow, open-ended cylinder into the container with the distal end of the cylinder over and contacting the biomaterial throughout its full circumference. These steps are followed by applying compressible pressure on the cylinder thereby allowing a fluid-tight seal between the cylinder and biomaterial, followed by introducing animal cells and appropriate, supporting growth media to the cylinder and contacting the biomaterial with the cells and media, and next culturing the cells, followed by assaying the cells, and finally recovering the sample of biomaterial for additional study, assays, and observations.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 illustrates the well plate insert.
FIG. 2 provides a cross-section view of a well plate and its relationship to the biomaterial and cylinder.
FIG. 3 illustrates the base that supports the well plate and is connected to the sleeve insert.
FIG. 4 provides a cross-section diagram of a well plate positioned in and supported by the base.
FIG. 5 is a cross-section illustration of the platform connected to the base and the relationship of the well-plate insert, platform, cylinders, and connectors
FIG. 6A illustrates adaptation of the cylinder to facilitate sealing biomaterial disks with a compressible O-ring positioned in the distal end of the cylinder.
FIG. 6B illustrates an alternative adaptation to sealing biomaterials of different thicknesses by fabricating a portion of the cylinder with a compressible material, such as rubber.
FIG. 7A illustrates a modified platform to accommodate a moveable cylinder.
FIG. 7B provides illustrates modifications of a cylinder to permit unidirectional movement in a modified platform.
FIG. 7C illustrates interlocking surface of the platform and cylinder.
FIG. 8 illustrates adaptation of bioassay apparatus to biomaterials of different thicknesses.
FIG. 9 illustrates the four major elements of a bioassay apparatus.
FIG. 10 provides an angular top view of the nested bioassay apparatus.
FIG. 11 provides a front view of the nested bioassay apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Detailed Description of the Figures
FIG. 1 illustrates a well plate insert 1 with a platform 2 with a bottom surface 3 , a top surface 4 , a cylinder 5 , with an open longitudinal core traversing the platform 2 from the top surface 4 to the bottom surface 3 , and the cylinder 5 having a lower portion 7 extending below the platform 2 , a distal end 9 , a proximal end 8 and an outside diameter 6 . Apertures 13 are positioned for connectors 11 to physically connect the platform to the base 30 . The cylinder 5 traverses the platform 2 and is either molded as part of the platform 2 or secured to an aperture traversing the platform 2 (aperture not illustrated).
FIG. 2 describes the spatial relationship of the lower portion of the cylinder 7 , the well-plate 21 with well 23 having a sample of biomaterial 25 positioned on the floor 24 of well 23 . The outer diameter 6 of the lower portion of the cylinder 7 is less than the diameter of the well 26 such that the the lower portion of the cylinder 7 can be inserted into the well 23 with the distal end of the cylinder 9 contacting the biomaterial 25 and creating the potential to form a fluid-tight seal at the point of contact 27 .
FIG. 3 describes a rectangular base 30 capable of supporting a multi-well plate (as illustrated in FIG. 2 ) and of being connected to the platform 2 of the well plate insert 1 by means of threaded connectors 11 . The base 30 comprises a back piece 31 , a front piece 32 , and side pieces 33 . A ledge 34 is created by a groove on the interior of the front, side, and back pieces. The width 35 and length 36 of the ledge are determined by the corresponding dimensions of the well plate to be supported. Threaded apertures 10 are defined by the edge of the base, and positioned to align precisely with corresponding apertures 13 in the platform 2 to receive threaded connectors 11 .
FIG. 4 illustrates a cross-section of the base 30 with a well-plate 21 . Well-plate 21 , including wells 23 , is illustrated here positioned on ledge 34 formed on sidewalls 33 of base 30 . Threaded apertures 10 are positioned to correspond to and align with apertures 13 of the platform 2 .
FIG. 5 illustrates in cross-section the spatial and functional relation of the components. Well plate 21 is positioned on ledge 34 of side wall 33 of base 30 . Cylinder 5 is connected to platform 2 with lower portion of cylinder 7 extending below bottom surface of platform 3 . Biomaterial 25 is positioned on floor of well 24 . Distal end 9 of cylinder 5 is inserted in well 23 and contacts biomaterial 25 . Apertures 13 in platform 2 and threaded apertures 10 in base 30 align such that connectors 11 physically connect platform 2 and base 30 . Tightening connectors 11 creates the potential of a fluid-tight seal at the distal end of the cylinder 9 , between the biomaterial 25 and cylinder 5 by bringing well plate insert 1 relatively closer to base 30 thereby producing a compressive force on the interface 27 of the distal end 9 of the cylinder 5 and the biomaterial 25 .
FIG. 6A illustrates a longitudinal cross section of the cylinder 5 adapted to position and hold a compressible gasket or O-ring 61 on the distal end of the cylinder 9 . A groove 63 to receive the O-ring 61 is formed in the distal end face of the cylinder 64 . The O-ring 61 fits into the groove 63 with approximately one-half of its thickness 65 exposed to form a seal with the biomaterial 25 . This creates the potential to form a fluid-tight seal between the O-ring 61 and biomaterial 25 when compressed as a result of the compressive connection joining platform 2 and base 30 .
FIG. 6B illustrates the position of a compressible material as a segment of the lower portion of the cylinder 7 . Cylinder 5 traverses platform 2 , and lower portion of cylinder 7 extends below the bottom surface of the platform 3 . Any portion of the length 67 of the lower portion of cylinder 7 starting at point 66 of the lower portion of the cylinder 7 and extending towards the distal end of the cylinder 9 may be fabricated from a compressible material such as, but not limited to rubber. This portion 67 serves essentially the same function as the previously described function of O-ring 61 .
FIG. 7A describes a modification of the platform 2 in which an opening 70 with a diameter 71 traverses the platform 2 from its top surface 4 through its bottom surface 3 . Opening 70 is defined by a wall 72 with horizontal, uniformly spaced ridges 73 formed on the surface of the wall 72 . One skilled in the art would recognize that, alternatively, the ridges 73 may be formed and characterized as threads.
FIG. 7B describes modifications of cylinder 5 that permits only unidirectional movement of cylinder 5 through opening 70 in platform 2 . Uniformly spaced, horizontally parallel ridges 75 are formed over at least a portion of the outer surface 76 of the cylinder 5 . The ridges 75 are spaced and shaped to permit cylinder 5 to be inserted at the top surface 4 of platform 2 and to move downward. The configuration prevents opposite movement. One skilled in the art would recognize that, alternatively, the ridges 75 may be formed and characterized as threads that circumscribe the outer surface of the cylinder 76 . The threads are adapted to receive threads formed on the surface of wall 72 . In this configuration, the cylinder may be moved upward or downward by reversing the rotation of the cylinder as it is inserted in opening 70 .
FIG. 7C details how relative movement of the cylinder 5 through opening 70 is restricted. When cylinder 5 is inserted in opening 70 , the flat surface 77 of ridge 75 formed on cylinder 5 contacts the corresponding flat surface 78 of ridge 73 formed on wall 72 of opening 70 in platform 2 . Opposing flat surfaces resist upward pressure, arrow 81 , of the cylinder 5 in relation to platform 2 . Corresponding beveled surfaces on the cylinder 79 and beveled surfaces on the platform 80 will allow downward movement of cylinder 5 through opening 70 in platform 2 . Thus, when platform is physically linked to base, and cylinder is inserted into a well, downward pressure relative to platform on cylinder can create a fluid-tight seal to be maintained between the distal end of the cylinder and biomaterial positioned on the floor of the well.
FIG. 8 illustrates cylinders 5 A and 5 B traversing corresponding openings 70 A and 70 B in platform 2 . Distal ends 9 A and 9 B of corresponding cylinders are inserted into corresponding wells 23 A and 23 B of multi-well plate 21 . Platform 2 is connected to base 30 by connectors 11 . Samples of biomaterial 25 A and 25 B of different thicknesses are positioned in corresponding wells 23 A and 23 B. Interlocking ridges 73 and 75 formed on the adjacent, opposing surfaces of cylinders 5 A and 5 B and corresponding wall of opening 72 A and 72 B allow cylinders to be pressed downward so that contact is made with biomaterial samples. Biomaterial sample 25 B for illustrative purposes is thicker than biomaterial sample 25 A.
FIG. 9 illustrates the four basic elements of a bioassay apparatus 100 . When assembled the units are stacked in a nested configuration. Base unit 30 serves as a rectangular frame capable of supporting multi-well cell plate 21 . By way of illustration, but not limitation, multi-well cell plate 21 comprises six wells 23 . The well plate insert comprises one or more cylinders 5 that traverse a platform 2 and are structurally attached to the platform. Edges of the platform further define a plurality of apertures 13 . Lid unit 90 rests on and covers the proximal ends 8 of the cylinders 5 .
FIG. 10 describes and illustrates the relationship of the elements of a bioassay apparatus 100 from the perspective of an angular top. Multi-well plate 21 is nested into base 30 . Distal ends (illustrated as 9 in FIG. 1 ) of plurality of cylinders 5 are inserted into wells 23 of well plate 21 . Connectors 11 are inserted through apertures 13 and are threaded into threaded apertures 10 and tightening connectors 11 creates a compressive force at point of contact 27 of cylinder 5 and biomaterial 25 . Lid unit 90 fits over the proximal ends of cylinders (illustrated as 8 in FIG. 1 ) and fits nest fashion on platform 2 .
FIG. 11 provides a face on view of bioassay apparatus 100 . Multi-well plate 21 is positioned on ledge 34 formed by groove in base 30 . Well plate insert 1 is positioned above multi-well plate 21 with cylinders 5 inserted into wells 23 . Connectors 11 are fully tightened producing a compressive force at interface of distal end of cylinder and biomaterial positioned on floor of well 23 .
EXAMPLE I
As seen in reference to FIG. 9 , the major elements of a bioassay apparatus 100 are the base 30 , a multi-well plate 21 with a plurality of wells 23 , a well plate insert 1 comprising a plurality of open ended, hollow cylinders 5 attached to a platform 2 , and a lid 90 . Details of these elements and their spatial and functional relationships are described in the following example and discussion of certain figures.
As seen in reference to FIG. 3 , a base 30 is provided which may be in the form of a rectangular frame. An outer margin of the frame can define a plurality of threaded apertures 10 . An upper surface of the base defines a ledge 34 formed by a notch or groove which further defines a receiving surface for a conventional multi-well plate 21 (as illustrated in FIG. 2 ).
As seen in reference again to FIG. 9 , multi-well plate 21 may be provided by a conventional six-well plate as are commercially available from, for example Fisher Scientific, Pittsburgh, Pa. 15275. While the illustrated embodiment provides for a six-well plate, the number, size, and spacing of the individual wells can vary. The ledge 34 on the interior of the base 30 is adapted for nesting with the lower rim of the multi-well plate 21 .
As seen by FIG. 5 which represents the detail of only one of a plurality of wells 23 and associated elements of the assay apparatus, open-ended, hollow cylinder 5 traverses the platform 2 of the well plate insert 1 . Cylinder 5 is formed as part of, or attached to platform 2 . A lower portion 7 of cylinder 5 extends below the bottom surface of the platform 2 . The proximal end 8 (as illustrated in FIG. 1 ) of the cylinder 5 extends above the top surface of the platform 2 . Thus each of the plurality of cylinders 5 corresponds to one well 23 of the plurality of wells in a multi-well plate 21 , and the cylinder 5 allows access via the proximal end 8 of the cylinder 5 through the platform 2 to the distal end 9 of the cylinder 5 . The bottom edges of the multi-well plate 21 are nested within the groove of the corresponding edge of the base resting on and supported by the ledge 34 . A sample of biomaterial 25 is positioned on the floor of a well. The distal end 9 of the cylinder 5 is inserted into the well 23 and contacts the biomaterial 25 . Both the well-plate insert 1 and the base 30 further define a plurality of threaded apertures 10 which are vertically aligned when cylinders 5 are inserted into corresponding wells 23 in the multi-well plate 21 positioned on the base 30 , and the bioassay apparatus 100 (as illustrated in FIG. 9 ) is in a stacked configuration. Threaded connectors 11 inserted through the apertures 13 and 10 connect the well plate insert 1 and base 30 and provide a means of exerting a compressive force between these elements by tightening the connectors 11 . It is to be noted that FIG. 5 represents and illustrates only a single cylinder-well association in a cross-section view from the front of a bioassay apparatus 100 . Reference to FIG. 9 illustrates a configuration with six wells 23 , by means of example, not limitation.
As seen in reference to FIG. 9 , a lid 90 is provided having an upper surface and a lower surface. A lower surface of the lid 90 is surrounded by a protruding flange which extends around the perimeter of the lid 90 . As seen in further reference to FIG. 10 , the lid has a similar size and shape to the platform 2 , which is adapted to engage the lid 90 . The inner surface of the lid 90 defines a plurality of circular ridges which correspond to the proximal ends 8 of each cylinder 5 . For purposes of this invention, it has been found that a conventional lid 90 of commercially available multi-well plates 21 may be used. Fisher Scientific, Pittsburgh, Pa. 15275.
As best seen in reference to FIGS. 10 and 11 , the assembled bioassay apparatus 100 uses the base 30 to engage a lower surface of a multi-well plate 21 . Next, the well-plate insert 1 (as illustrated in FIG. 5 ) is positioned over the multi-well plate 21 . As seen in the referenced figures, for each well 23 within the multi-well plate 21 a corresponding cylinder 5 can be provided and appropriately spaced so as to align each cylinder 5 with a corresponding well 23 .
When so aligned, the apertures defined on the edges of the platform 2 (as illustrated in FIG. 5 ) and base 30 are aligned so as to receive a threaded connector 11 such as a bolt or screw. In this manner, the threaded connectors 11 can be used to apply a compressive force between the lower ends 7 of the cylinder 5 and the corresponding bottom portion of the multi-well plate 21 . The lid 90 may then be placed over the top surface 4 of the platform 2 , the lower surface of the lid 90 being in contact with at least the proximal end 8 of each cylinder 5 , which extends above the upper surface of the platform 2 .
As best seen in reference to FIG. 5 , the bioassay apparatus 100 can be used to test the compatibility of various biomaterials 25 as they are placed in contact with a test medium, which may contain living cells. For instance, a sheet of biomaterial 25 may be provided in which circular portions of a biomaterial 25 are cut and sized so as to be placed on the floor 24 of each well 23 of the multi-well plate 21 . Thereafter, when the well-place insert 1 is brought into engagement with the multi-well plate 21 , the engaging cylinder walls are placed in contact with the biomaterial 25 . As seen in reference to FIG. 6A , a lower edge of each cylinder wall can support a corresponding “O” ring 61 or similar flexible gasket-like material. When the gasket material of the lower sleeve wall is brought in contact with the biomaterial, a seal, which may be fluid tight, results. The use of the threaded connectors 11 helps maintain the necessary compressive force between the cylinder 5 and the biomaterial 25 which may provide and maintain a fluid-tight seal. While threaded connectors are illustrated in the preferred embodiment, it is recognized that there are alternative means of supplying a suitable compressive force between the cylinder 5 and the biomaterial 25 . For instance, spring-loaded clips could be used to secure the margins of the platform 2 to the base 30 . Likewise, clamps or other tensioning devices may be used to supply the necessary compressive force.
For instance, by selecting the use of dense materials such as glass or dense plastics, the weight of the well-plate insert 1 could be sufficient to provide a necessary compressive force.
As is readily appreciated by one having ordinary skill in the art, the amount of compressive force that needs to be supplied would vary depending upon the presence of a gasket or other sealing material. Additionally, some biomaterials may have sufficient physical properties that a seal can be formed without the necessity of a separate gasket. In addition, it is recognized that depending upon the texture and surface features of the biomaterial being assayed, a rough or textured material may require a more specialized gasket and/or increased compressive forces to bring about an effective seal. In specific cases a seal is not necessary or will not be possible. In these cases the insert will simply position the material.
Once a seal has been established, a test medium, for example a population of cells and growth media may be introduced through the upper opening defining each cylinder and brought into contact with the biomaterial. In this manner, the biomaterial is maintained in intimate contact with the growth media and resident population of cells. The biomaterial is firmly held in place by the compressive forces of the cylinder walls. Accordingly, the biomaterial is immobilized which eliminates cell damage attributed to movement of the biomaterial.
The above described embodiment is preferred in that it makes use of conventional and readily available multi-well assay plates. However, the process of carrying out the biomaterial assay can employ a variety of different apparatuses. For instance, a base unit may be provided in which a flat sheet of biomaterial is placed. A hollow cylinder-like structure may thereafter be brought into contact with the biomaterial so as to bring about a fluid-tight seal between the biomaterial and the engaging cylinder surface. An upper opening in the cylinder can provide an entry way for the addition of a cell culture and growth media. In this arrangement, a conventional assay plate is not needed in that the hollow cylinder is used to define an enclosure relative to the biomaterial which can contain the cells and media.
The entire device may be made of any materials that tolerate sterilization. In a preferred embodiment, the material is polystyrene. The invention anticipates a variety of materials including, but not limited to, appropriate polymers, glass, and metals.
EXAMPLE II
As seen by reference to FIG. 8 , illustrating a well plate 21 with two wells 23 , the current invention may be adapted for the study of biomaterials 25 of significantly different thickness. The number of wells 23 is for illustration purposes and not as a limitation. As seen by reference to FIG. 7A , a cylinder 5 adapted with closely spaced ridges, teeth, or serrations 75 in horizontally parallel arrangement along part of its exterior surface. Reference to FIG. 7B illustrates corresponding structures. The serrations 75 circumscribing the walls 72 define an aperture 70 in the platform 2 . Reference to FIG. 7C illustrates how a cylinder 5 inserted into the aperture 70 moves downward, but the shape and structure of the serrations 75 on the opposing surfaces of the aperture 70 and cylinder 5 for a locking interface that allows downward movement and restricts movement upward. The seal is created by tightening the connectors. Any previously described modification to the cylinder to enhance sealing may be incorporated into the cylinders employed in this example. This example requires the use of individual lids for each cylinder. Common types of commercially available laboratory petri dish lids have been found to be suitable. Fisher Scientific, Pittsburgh, Pa. 15275.
One of average skill in the art would recognize that the threads on the opposing faces of the cylinder and wall of the aperture in the platform could replace the serrations. In this configuration, the cylinder could be screwed into the aperture and depth adjusted in either an upward or downward direction. All other aspects of the invention remain as described, discussed and illustrated. In this configuration, the cylinder represents the male unit and the aperture the female unit. Regardless of the configuration, as can be inferred by reference to FIG. 7C , the sensitivity of the adjustment is a function of the space between serrations or the number of threads per centimeter of length of the cylinder or aperture.
EXAMPLE III
As seen in reference to FIG. 6B , a segment of the lower portion 7 of the cylinder 5 can be fabricated with a compressible material such as rubber. This adaptation serves the same function as the interlocking ridges and moveable cylinders, which is to accommodate biomaterials of different thicknesses. Thus, the modification described in FIG. 6B is appropriate for uses described in Examples I and II. | An apparatus to facilitate precise and efficient evaluation of biomaterials using direct contact cell culture techniques. The apparatus positions the biomaterial and creates the potential to form a fluid-tight seal between the biomaterial and the apparatus, at which point the biomaterial is exposed to cells and/or media. An assay method based on the apparatus is claimed. | 2 |
BACKGROUND
The present invention generally relates to electrical filters and in particular to demultiplexers for frequency division multiplexed (FDM) signals.
Filters for electrical signals exist in both analog and digital form. Analog filters are constructed with components whose number and precision increases with the desired precision in the filtered signal. Digital filters can provide precise filtering but require a large number of samples, and thus a high sampling rate, when a large bandwidth of signals is to be filtered. Accordingly, there is a trade-off between digital and analog filters depending upon the application for which the filtering is to be used.
Frequency selective filters and down converters have been used for many years in communication applications. An example of a simple unit of this type is the standard AM broadcast receiver. In the communications world, a typical application is the demultiplexing of frequency division multiplexed (FDM) signals. These signals are created by single-sideband modulation (conversion) of 4 kilohertz (kHz) bandwidth channels and placing the modulated signals in a channelized spectrum relative to a carrier frequency. The function of the demultiplexer is to select one of a set of modulated signals that have been multiplexed together in frequency, convert that signal to its original baseband form, and output the baseband signal either in analog or digital form. In analog technology, a typical implementation is the use of a double superheterodyne single-sideband receiver. Such an implementation requires complex crystal filters. The incoming signal is mixed with a controlled oscillating signal to produce a higher frequency signal which will be within the range of the crystal filter for the demultiplexer. The particular frequency to be received can be selected by tuning the oscillator for the controlled frequency signal so that the resultant heterodyned signal of higher frequency will be within the range of the filter. The filtered signal is then converted down to the baseband audio frequency range where the signal can be understood by a person.
A separate analog filter is required for each channel. Cumulative bandwidths on the order of 15 megahertz (MHz) are typically obtainable.
When a digital filter is used instead, the signal must be converted from an analog signal to a digital signal and then passed through a digital filter. The digital filter can be constructed using fast Fourier transforms in which the signal is broken down into its separate frequency components and each component is multiplied by a predetermined coefficient to produce the filtering desired. The drawback of digital filtering is the large number of computations required, which limits the bandwidth attainable. Bandwidths for digital implementations are typically limited to approximately 1 megahertz with currently available hardware.
SUMMARY OF THE INVENTION
The present invention provides a filter which uses both an analog portion and a digital portion to optimize filter performance. A simple analog bandpass filter provides an initial coarse filtering of the input signal. The output of the analog filter is converted into digital form and supplied to a digital filter. The coefficients defining the characteristics of the digital filter are changed by a digital computer in order to correct for the errors in the filtered signal produced by the analog filter. The coefficients necessary for the digital filter to provide an error offset are determined by comparing the filtered value of a test signal through the analog filter to an ideal filtered value of such test signal.
Preferably, an input signal is mixed with a fixed frequency signal to convert the entire baseband up to a higher frequency which is then filtered by a bandpass filter. The resultant signal is applied to a pair of mixers where it is modulated by the in-phase components and the quadrature components of a variable frequency signal which can be tuned to the desired channel. The output of each of these mixers is applied to a separate analog linear-phase, low-pass filter. The outputs of the two linear-phase, low-pass filters are applied to an analog-to-digital converter and then to a digital filter. The coefficients of the digital filter are controlled by a digital computer which is also coupled to the output of the analog-to-digital converter so that it may sample the analog filter output of a test signal.
The digital filter performs complex filtering but has its coefficients adjusted to shift the output frequency to produce a real signal output. Complex value filtering is needed to produce a quadrature component so that the phase of the signal can be adjusted.
By combining analog and digital techniques, the present invention eliminates the need for an analog filter with a large number of high precision components, allowing a simple analog filter to be used instead. In addition, the digital filter used need not have a high sampling rate because the analog filter has performed a large amount of the required filtering already.
Because the digital filter can adjust for errors, the two analog filters do not need to be closely matched, as required for prior art analog filters. In addition, the phase shifting to give the quadrature component of the variable frequency signal need not be precise.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a frequency division demultiplexer according to the present invention;
FIG. 2 is a flowchart of a program for the digital computer of FIG. 1 controlling the operation of the embodiment shown in FIG. 1;
FIG. 3 is a graph of the output characteristics of a general digital filter of FIG. 1;
FIG. 4 is a graph of the output characteristics of an analog 5 pole linear phase filter of FIG. 1;
FIG. 5 is a block diagram of the demultiplexer of FIG. 1 adapted to simultaneously process several channels for each baseband;
FIG. 6 is a graph of the response to a specific input of the analog filter of the embodiment of FIG. 1; and
FIG. 7 is a graph of the response to a specific input of the embodiment of FIG. 1 after correcting coefficients for the digital filter have been calculated and implemented.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a preferred embodiment of a demultiplexer 10 according to the present invention. A separate demultiplexer circuit 12, 14 is provided for each baseband channel to be demultiplexed. The components of circuit 14 mirror those of circuit 12 with a different bandpass filter 22 being used for the different baseband. Additional demultiplexer circuits can be added if additional baseband channels are to be demultiplexed.
Looking at demultiplexer circuit 12, an input signal 16 is applied to a mixer 18 which is also supplied a signal of fixed frequency from an oscillator 20. Mixer 18 serves to heterodyne the signal, producing a higher frequency signal which is filtered in an analog bandpass filter 22. The output of filter 22 is applied to a pair of mixers 24, 26. Mixer 26 is used to combine the signal with an in-phase frequency from an oscillator 28, while mixer 24 uses the quadrature component of the same frequency signal which is phase-shifted by a 90° phase-shifter 30. The frequency of the channel to be selected is determined by a tuner 32 which controls the frequency of oscillator 28.
The outputs of mixers 24, 26 are applied to analog linear phase low-pass filters 34, 36 respectively. The output of filters 34 and 36 are supplied to an analog-to-digital converter 38 and then to a digital filter 40. The output of digital filter 40 is applied to a digital-to-analog converter 42 and to a CODEC filter 44. The coefficients of digital filter 40 are set by a digital computer 46.
If a 15 MHz baseband is used for input 16, oscillator 20 can be used to provide a signal out of mixer 18 that is centered on 30 MHz and extends from 22.5 MHz to 37.5 MHz . Since the whole baseband is being up-converted, conversion filter 22 can be a very simple filter. Only the direct feedthrough signal from 0 to 15 MHz need be attenuated strongly. In an application where multiple channels are to be demultiplexed, this up-conversion need be done only once for each of the basebands to be processed (i.e., once for circuit 12, once for circuit 14, etc.)
Once the signal is up-converted, the down-conversion and selection process can begin. The in-phase component and the quadrature phase component of the signal from oscillator 28 are applied to mixers 24 and 26 to produce a second intermediate frequency (IF) signal centered at 0 (zero) Hertz in frequency. The signals to be selected are tuned by using tuner 32 to vary the frequency of oscillator 28 so that the resultant signal from mixers 24 and 26 will be at 0 (zero) Hertz in frequency. The difference frequencies between -2 kHz and +2 kHz are the selected frequencies. The negative frequencies are handled by processing both the in-phase component and the quadrature component of the signal.
In a completely analog system, mixers 24 and 26 and filters 34 and 36 would have to be very carefully designed so that the quadrature and in-phase components of the signal are processed in the same manner. The present invention can compensate for differences in phase and amplitude produced by mixer 24 and low-pass filter 34 as compared to mixer 26 and low-pass filter 36. This compensation is accomplished by varying the coefficients of digital filter 40.
The operation of digital computer 46 of FIG. 1 can be understood with reference to the flowchart of its programmed operation in FIG. 2. Computer 46 first operates to throw a switch 48 to provide a test signal from test signal generator 50 to mixers 24 and 26 (Step A). Computer 46 then samples the output of A/D converter 36 (Step B) to determine the error in the output of filters 34, 36. The error is the difference between the received sample values and the ideal filtered values stored in the memory of computer 46 (Step C). The measured errors are then used to calculate the proper coefficients for digital filter 40 to compensate for the errors in analog filters 34 and 36 (Step D). Computer 46 then sets the coefficients of digital filter 40 to the desired value (Step E). Switch 48 can then be switched back to receive the input from bandpass filter 22 and normal processing can take place (Step F). The output of digital filter 40 is converted back to analog by D/A converter 42, if necessary. The output of D/A converter 42 is supplied to a CODEC (coder-decoder) filter 44 which removes the aliased frequencies, as required, and corrects for the sin x/x filtering characteristics of the sample and hold circuitry of digital-to-analog converter 42.
In more detail, the errors in the implementation of the analog portions of circuit 12 can be measured at digital filter 40 by introducing a sine wave from test signal generator 50 that is within the desired passband. At the output of analog-to-digital converter 38, what should appear at steady state is a sine wave in the in-phase leg of the unit and a sine wave of exactly the same amplitude in the quadrature leg that is 90° out of phase with the signal in the in-phase leg. The amplitude error can be measured by measuring the amplitudes of the two sine waves over time. The phase error can be measured by comparing the phase of the two signals.
To measure the amplitude and phase errors of the signal, a block of data in the digital filter must be collected for a measurement. The block of data should cover many cycles of the test signal to make the measurement accurate. A block of one hundred cycles of the data is adequate to measure the error with a signal-to-measurement error ratio of 50 dB. To measure the amplitude of the signal, computer 46 averages the difference between each negative peak and the following positive peak over 100 cycles. To measure the amplitude difference, computer 46 calculates the ratio of the two amplitudes.
To measure the phase difference, computer 46 multiplies the output of the in-phase component and the output of the quadrature component together and averages them over 100 cycles. The averaged product is proportional to the amplitude product of the two signals times the phase difference in radians. Since the amplitudes of the two signals are known from the measurement of the amplitude, the amplitude effects can be taken out, leaving a measure of the phase. The technique is much the same as used in phase measuring devices and phase locked loops except that no hard limiting is done. As a consequence, the amplitude corrections must be made in order to measure the phase error.
The basic design of digital filter 40 is performed in a straightforward manner. Several filter design routines are available for the determination of the coefficients of a finite impulse response filter. The application of a McClellan-Parks design routine to the design of a symmetric filter covering 64 points results in the filter whose bandpass characteristic is shown in FIG. 3.
This filter provides a filtering operation that passes the frequencies from -1700 Hz to +1700 Hz. The filter rolls off to more than 50 dB down in the very short space of 300 Hz. The filter coefficients are symmetric, so the filter introduces absolutely zero group delay distortion, a very desirable characteristic for a selection filter.
The basic filter may be modified to correct for the bandpass errors of the preceding analog filter. To make the analog filter easy to construct, it is convenient to make the filter a linear-phase filter. The bandpass characteristic of a five-pole linear-phase filter is shown in FIG. 4. The filter characteristic rolls off slowly, making the peak of the filter pass band characteristic quite round. The digital filter pass band characteristic may be modified to correct for the pass band characteristic of the preceding analog filter by correcting the pass band of the digital filter to compensate for the errors in the analog filter pass band. The resulting composite pass band is essentially that shown in FIG. 3, the same characteristic as the original filter. However, since the signal has already been through the analog filter, the characteristics of FIG. 3 can be obtained with a lower sampling rate. A sampling rate 1/10 of that required for a totally digital filter can be obtained. Alternately, the bandwidth can be increased by a factor of 10 at the same sampling rate.
Once the error has been measured, it can be corrected. The correction can be performed by modifying the coefficients of digital filter 40. The quadrature component may be made to be 90° out of phase with the in-phase component by subtracting from the quadrature component the in-phase component multiplied by the sine of the phase error. When the averaged cross product is taken with the correction made to measure the residual error, the subtracted component will balance the phase error, demonstrating that the two signals are 90° out of phase.
Once the phase has been corrected, the amplitude may be corrected. The amplitude of the in-phase component may be taken as a reference, and the amplitude of the quadrature component modified by changing the coefficients of the filter. Those coefficients that act to produce the quadrature component digital filter output need to be multiplied by the reciprocal of the ratio of the quadrature amplitude to the in-phase amplitude as measured. The result will be that the in-phase amplitude will be the same as the quadrature amplitude to within the accuracy of the measurement and the accuracy of the arithmetic (usually integer) used in the computations.
The complex coefficients of the basic digital filter may be modified to perform the manipulations of phase correction and amplitude correction described above. The gain of the signals through the in-phase and quadrature channels may be modified by changing the coefficients. For example, the gain of the in-phase component through the quadrature channel may be adjusted to remove an in-phase component in the quadrature channel. If a leakage component of 10% of the in-phase component appears in the quadrature channel, it may be removed by using a filter coefficient set that multiplies the in-phase component by -0.1, and then by adding the result to the quadrature component.
More generally, the amplitude and phase characteristics at a number of frequencies across the pass band may be measured. The digital filter coefficients may be adjusted [using techniques available to those knowledgeable in the art]to adjust the phase and amplitude characteristics to compensate for the phase and amplitude errors of the analog filter. The digital filter will typically have enough coefficients for very fine adjustment of the filter characteristics.
The signal that comes through the digital filter is a signal that is centered on zero Hertz frequency. The use of the zero Hertz center frequency makes the digital filter simple to construct. To be useful, the output signal must be shifted to be a real signal (centered on two KHz in this embodiment). With a sample rate that is four times the center frequency, this frequency shift is particularly simple. A complex sine wave at two kHz when sampled at eight kHz has only four values, (1,0), (0,1), (-1,0), (0,-1). The mixing operation corresponds to multiplying by plus or minus one. Furthermore, half of the multiplications are multiplications by zero and need not be performed.
To make the signal real, the quadrature component of the signal is discarded. As a consequence, the quadrature component need not be computed.
The required set of computations is then the computation of the in-phase component at one sample time, the quadrature component the next sample time, the negative of the real component the next sample time, and the negative of the quadrature component the next sample time. After that the cycle repeats. The actual set of computations consists of the computation of only one of the two components of the output of the filter at any one sample output.
The completion of the operation is straight-forward. The real signal is passed through a digital-to-analog converter 42 to convert it to analog form. Analog filter 44 is applied to the output to correct for the sin x/x bias introduced by the conversion and to suppress the aliased signals that lie above the pass band of the signal. In the embodiment shown, the filter can be a very inexpensive filter known in the industry as a CODEC filter, used for just these purposes in digital telephony.
The up conversion process applies to all of the channels of the baseband at one time. It need not be done for each channel that is to be processed, only for each baseband that is to be processed. After the up conversion, thee is a basic analog process that must be performed for each channel that is to be processed. The process consists of the down conversion to the zero Hz IF frequency and the coarse filtering of the analog low-pass filters.
In one embodiment, shown in FIG. 5, the digital processing is performed on multiple channels at one time. Analog-to-digital converter 38 is preceded by a multiplexer 56 that presents the signals that are to be converted to the sample and hold that is part of analog-to-digital converter 38. In this manner many signals may be converted with the same circuit 52 or 54.
The elements that perform the digital processing have a capacity for computation that exceeds that required for a single channel by a large margin. Once the conversion to digital form has been made by A/D converter 38, the signal samples are buffered by buffer 58 for filtering by digital filter 40, which can compute the required outputs for many signals at once. Once the signals are available for digital-to-analog conversion, the distribution to multiple analog outputs must be performed. There are as many D/A converters 42 and CODEC filters 44 as there are channels to be processed.
In applications where a digital form of the filtered output is appropriate, the output of the digital filter may be retained in a time division multiplexed form for distribution as required.
FIGS. 6 and 7 illustrate the utility of the technique of the present invention. In FIG. 6 the spectrum of a signal where there has been no correction of the errors of the analog filter is shown. The amplitude errors are five percent and the phase error is five degrees. The result is an image of the input sine wave that is less than 20 dB below the signal itself. The image must be suppressed to form a good demultiplexer.
In FIG. 6 the corrections have been made using the coefficients of the digital filter. The results show that the image has been reduced by more than 20 dB. More careful estimation of the phase and amplitude error can reduce the image even further.
As will be understood by those familiar with the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. For example, a combination analog and digital filter could be used in other applications than frequency division demultiplexing. Accordingly, the disclosure of the preferred embodiment of the invention is intended to be illustrative, but not limiting, of the scope of the invention which is set forth in the following claims. | A filter which uses both an analog portion and a digital portion to optimize the filter performance. A simple analog filter provides a rough filtering of the input signal. The output of the analog filter is converted into digital form and supplied to a digital filter. The coefficients of the digital filter are changed by a digital computer in order to correct for the errors in the filtered signal produced by the analog filter. The coefficients necessary for the digital filter to provide an error offset are determined by comparing the filtered value of a test signal through the analog filter to an ideal filtered value of such test signal. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a pulley apparatus and, more particularly, to a novel hydraulically actuated pulley apparatus adapted to be attached to a member of a structural body, such as an automobile, for pulling the member with respect to the body for moving, straightening or performing any other desired work on the member or the body itself during the repair thereof.
2. Description of the Prior Art
Heretofore, it has been the conventional practice to use handtools, such as angle irons and crowbars in repairing automobile body parts. The advantage in using such tools is the easy maneuverability of the tools and the ready access that these tools permit in reaching these parts. Although these tools have been successfully employed in the past, several problems and difficulties have been encountered which severely limit their utilization.
On occasions when a large amount of force is needed in pulling or straightening body members, the pulling force generated by these leverage tools is usually insufficient to move these members. Furthermore, in order to gain any leverage, the body members sometimes act as a fulcrum for the tools. This oftentimes results in marring the appearance of or even damaging the members, which, of course, is undesirable. What is often required in aligning or straightening a body member is a steady continuous force acting to move the member only a few inches, but to an exact position. A common fault of the handtools is overpull, where a short burst of force carries the member past its intended aligned position.
It is recognized therefore, that in many situations some mechanical apparatus must be used in providing the means for working on automotive body members. A common means used is a pulley arrangement such as a block and tackle apparatus. In such a device, the mechanical advantage developed by the pulleys provides the pulling force that is required. However, such devices are usually not maneuverable enough to permit widespread usage and often require overhead beams, cranes, and other expensive and unwieldy apparatus. As a general rule, the angle of the pulling force on a body member varies numerously, depending on the position of the member and the manner in which it must be straightened or aligned. Since the block and tackle must be anchored from the same angle as the direction of the pulling force, such a device is often impractical to employ because such various anchoring positions are not readily available or, in fact, possible.
SUMMARY OF THE INVENTION
Accordingly, the problems and difficulties encountered with the conventional means and apparatuses mentioned above are obviated by the present invention which provides a hydraulic pulley apparatus supporting a first cable or chain which is adapted to be attached to a workpiece from a variety of positions. The hydraulic pulley apparatus includes a frame having a base portion mounted on wheels for easy maneuverability and portability. The upper portion of the frame is anchored to a tiedown assembly by a second cable or chain. The first chain is adapted to be connected at one end to the workpiece and at the other end to attachment means located on the base portion of the frame. A hydraulic piston and cylinder combination is pivotally connected at one end to the base portion with a first pulley being connected to a piston rod extending out of the other end of the cylinder. A second pulley is rotatably mounted on the frame adjacent the anchored portion thereof. The two pulleys and the attachment means are arranged in such a fashion that the first chain extends from the attachment means, around the first pulley, then around the second pulley in the opposite direction, and finally to the workpiece, forming a modified S-shaped configuration. Upon actuation of the piston-cylinder combination, the piston rod extends out of the cylinder to move the first pulley away from the attachment means and the second pulley, thereby drawing the end of the chain, attached to the workpiece, toward the second pulley. A novel lock mechanism is provided for holding the chain under tension during the work operation to permit release of the hydraulic power for sequential operation of the hydraulic piston to obtain pulling action for greater distances than the length of the piston.
In one form of the invention, the apparatus is provided with a third pulley adapted to be mounted in various positions on the frame above the second pulley to receive the cable or chain extending from the second pulley to the workpiece. Securing means are mounted on the third pulley for anchoring the third pulley to the tiedown assembly.
In another form of the invention, the apparatus is provided with a fourth pulley freely mounted on the cable or chain located between the second and third pulleys to function as a block and tackle arrangement.
Therefore, it is among the primary objects of the present invention to provide a highly maneuverable pulley apparatus for working on body members of an automobile.
Another object of the present invention is to provide a portable pulley apparatus that is capable of varying the angle of pulling force acting on the body member.
Another object of the present invention is to provide a portable pulley apparatus that is operable by hydraulic actuation.
Another object of the present invention is to provide a portable pulley apparatus that can be transported and operated in many environments.
Still another object of the present invention is to provide a novel pulley apparatus that is capable of various adaptabilities for a variety of uses.
Still other objects, features and attendant advantages of the present invention, together with various modifications, will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in the several figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view, partly diagrammatic, illustrating a hydraulic pulley apparatus in accordance with the present invention in an operative position in connection with a body member;
FIG. 2 is a perspective view of the pulley apparatus showing the novel hydraulic actuating means;
FIG. 3 is an enlarged elevational view, partly broken away, of the pulley apparatus showing the cable or chain by broken lines;
FIG. 4 is a front elevational view of the pulley apparatus as seen from the left in FIG. 3;
FIG. 5 is a fragmentary plan view, partially in section, of the upper pulley, taken substantially along line 5--5 of FIG. 3;
FIG. 6 is a fragmentary plan view, partially in section, of the second pulley, taken substantially along line 6--6 of FIG. 3 and showing the locking means;
FIG. 7 is a fragmentary plan view, partially in section, of the chain attachment to the frame, taken along line 7--7 of FIG. 3;
FIG. 8 is a fragmentary view similar in aspect to FIG. 6 and showing the locking means in a different position; and
FIG. 9 is a diagrammatic elevational view of the pulley apparatus utilizing another arrangement of pulleys.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, hydraulic pulley apparatus in accordance with the present invention is indicated generally at 10 and is anchored as to a tiedown device 11 by means of a cable or chain 12, shown in broken lines. The pulley apparatus 10 can also be secured to the tiedown device 11 at a second lower position, indicated in phantom lines at 12'. This option depends on the position from which the pulley apparatus 10 is pulling a cable or chain, a first position chain being shown in broken lines at 13 and a second position chain being shown in phantom lines at 13'.
In the operative position in which the chains are shown in broken lines, the chain 13 extends from the pulley apparatus 10 and is connected to a body member or workpiece 14. The body member 14 is illustrative only, and may be a bent automobile frame requiring straightening, in which case it is shown securely anchored as to a second tiedown device 15 by means of a cable or chain 16 for restrained rigidity against the pull of the apparatus 10.
Referring now in detail to FIGS. 2 and 3, the hydraulic pulley apparatus 10 includes a frame 17 having a pair of bifurcated legs 18 integrally connected to a base platform 19 and being vertically supported by gussets 21. The platform 19 acts as the sole support of the frame 17 in its operable position. However, a pair of wheels 22 are connected to one end of the platform 19 and are utilized to transport the whole apparatus to various work stations.
Located between the legs 18 and integrally connected to the platform 19 is a notched attachment plate 23, adapted to receive the chain 13. A hydraulic cylinder 24 is also located between the legs 18 and is pivotally connected thereto by pin means 25. A piston is axially movable within the cylinder 24 and is hydraulically controllably actuated in the conventional manner. A piston rod 26 is connected to the piston, extends out of the free end of the cylinder 24, and is integrally provided at its free end with a yoke 26' upon which a first pulley 27 is rotatably mounted so as to rotate about a movable axis.
Also located between the base legs 18 is a second pulley 28 rotatably mounted on the base legs 18 at their union. A lock mechanism 29 is pivotally mounted on the legs 18 adjacent the second pulley 28. Located on a cross brace 31 integrally connecting the legs 18 is a hook 32 adapted for connection to the anchor chain 12' of FIG. 1.
A pair of stanchions 33 are integrally connected to the base legs 18 at their union and include a plurality of vertically spaced holes 34 for selectively receiving a pin 35 or 35'. The pin 35 is utilized to rotatably support a third pulley 36 in a plurality of vertical positions. The positioning of the pulley 36 depends on the height desired and the angle of the pulling force of the cable 13 required. A modified V-shaped member 37 is also pivotally connected to the pin 35 on both sides of the third pulley 36. A hook 38 is connected to the lower leg of the member 37 and is adapted for connection to the anchor chain 12 of FIG. 1.
Referring to FIG. 3, the chain 13 is adapted to operate in various configurations. In one circuit, one end of the chain 13 is connected to the attachment means 23. The chain 13 then extends horizontally to the first pulley 27, around the pulley 27 and then to the second pulley 28 in the reverse direction. The chain 13 then extends horizontally to the first pulley 27, around the pulley 27 and then to the second pulley 28 in the reverse direction. The chain 13 then extends around the second pulley 28 and finally in a horizontal direction to be attached to the body member 14. As can be seen, this first circuit forms a modified S-shaped configuration.
The second circuit illustrated shows the chain 13 extending from the attachment means 23, around the first pulley 27 and to the second pulley 28, as done previously. However, in this circuit, the chain 13 extends partially around the second pulley 28 and then vertically to the third pulley 36. The chain 13 then extends around the third pulley 36 and onward to the body member 14. In this modified S-shaped configuration, the upper loop of the "S" is larger than the lower loop. As previously stated, the height of the third pulley 36 can be adjusted as desired.
As more clearly shown in FIG. 4, the pins 35 and 35' can be easily removed for ease of installation and convertibility of the third pulley 36. It should also be noted that all three of the pulleys lie in the same vertical plane negating the possibility of developing any bending moments in the axial direction of the pulleys.
FIG. 5 shows a spring detent mechanism 41 including a bearing member 42 located on the member 37 and spring biased against the chain 13 as it extends over the third pulley 36. This detent mechanism 41 serves to retain the chain 13 in a taut condition between the pulleys 28 and 36 to prevent the occurrence of slack or twist in the chain.
Referring now in detail to FIGS. 6 and 8, the lock mechanism 29 includes a latch 45 pivotally mounted on a cross rod 46 secured to both base legs 18. The latch 45 is bifurcated to provide a pair of prongs 47 for engagement with the links of the chain 13. As illustrated by FIGS. 6 and 8, the latch 45 is axially movable along the cross rod 46. In FIG. 6, the latch 45 is in a center position whereby a link 49 in the chain is located between the prongs 47, which in turn engage the top side of the link 50 directly below the link 49 shown between the prongs 47. In FIG. 8, the latch 45 has been axially moved on its cross rod 46 to a side position whereby only one of the prongs 47 engages the inner portion of the registering link 50 by insertion therethrough. As seen most clearly in FIG. 3, the prong or prongs 47 bear against the pulley 28 to limit the upward rotational movement of the latch 45 to achieve the locking function. The positioning of the latch 45 is done manually depending on the registration of the chain links. The advantage of this adjustable locking means 29 is that it can engage and lock the chain 13 at any link when it is desired to lock the chain under tension, as when retracting the hydraulic piston 26 preparatory to a sequential stroke.
FIG. 7 more clearly shows the chain 13 being connected to the attachment means 23. This is accomplished simply by inserting the cross link of the chain 13 into the shot 48 for abutment obstruction retention of the next link.
Referring now to FIG. 9, the pulley apparatus has been modified to include a fourth pulley 51 acting as a block and tackle means. In this arrangement, the chain 13 extends from the attachment means 23, around the first and second pulleys 27 and 28, around the free-floating pulley 51 and finally is fixedly attached to the third pulley 36 or other securing means on the stanchions 33. The pulley 51 is then adapted to be hooked on to any workpiece such as the body member 14 or a chain thereto.
The operation of the pulley apparatus will be more clearly understood with reference to FIGS. 1 and 3. With the pulley apparatus 10 in the operable position where only the first two pulleys 27 and 28 are utilized, the chain 12' is connected to the lower hook 32 for anchoring to the tiedown device 11. The chain 13' is connected to the attachment means 23 and extends around the pulley 27. Initially, the piston rod 26 is located in its retracted position within the cylinder 24. Upon actuation of piston and cylinder 24, the piston rod 26 and its integral yoke 26' extend outwardly, moving the pulley 27 from its position shown in solid lines to a position shown in broken lines, the length of travel depending upon the length of the piston stroke. As the pulley 27 moves away from the attachment means 23 and the second pulley 28, the lower portion of the "S" is extended with the portion of the chain 13' ahead of the second pulley 28 being drawn over the second pulley 28. This obviously exerts a pulling force on whatever the object or body may be to which the free end of the chain 13' is attached, for performing work thereon in a direction toward the second pulley 28. If further work movement is required, the chain 13' is retained in its tensioned position at the pulley 28 by means of the lock mechanism 29, and the pulley 27 is then returned to its starting position by release of the hydraulic pressure in the cylinder 24. The chain slack below the pulley 28 caused by this retracting movement is then taken up by removing the chain from the attachment means 23 and manually pulling the chain taut again over the piston pulley 27. The registering link is placed into the attachment means 23 in this new location and the entire process is repeated as often as desired in order to pull the body member 14 or other object toward the second pulley 28. It should be noted that, in this operation, the horizontal component of the load on the chain 12' is equal and opposite to the horizontal component of the load of the chain 13' so that there are no resultant force components generated externally to cause an upsetting moment arm on the frame 17. Also, the external forces caused by the chains 12' and 13' act on a single point on the frame 17 thereby not causing any torsional effects within the frame. The frame 17, therefore, is perfectly stable with no need for further anchor means, it being noted that the resultant vertical force component of all external forces applied to the frame 17 is downward. Such a simple tiedown procedure greatly enhances the operability of the pulley arrangement since the apparatus can be easily maneuvered to various locations without the need of securing the frame 17 directly to the ground.
Furthermore, if a different angle or elevation of pulling force is required, the third pulley 36 is utilized. The pulley 36 is adjustable to various positions depending upon the attitude of the chain 13 required. This positioning is accomplished by inserting the pin 35 through any pair of holes 34 desired. When the position of the pulley 36 is fixed, the chain 12 is then secured to the hook 38. The operation of this arrangement is essentially the same as the previous operation, with the body member 14 being drawn toward the third pulley 36. In this arrangement, as before, the horizontal force components of the chains 12 and 13 are equal and opposite, the internal loads acting on the frame 17 are balanced and no torsional effects are produced. Therefore, the frame 17 is stable with no further anchoring means required.
The operation of the block and tackle means shown in FIG. 9 is also substantially the same as the previous operations with the pulley 51 being drawn toward the second pulley 28. Again it can be readily seen that the external and internal forces acting on the apparatus are balanced and the device is stable.
It is important to note that the cylinder 24 is pivotally connected to the frame 17 so that there is no binding of the piston rod 26 within the cylinder 24 due to any moment arm otherwise created by the force of the chain on the piston pulley 27. | Hydraulic pulley apparatus including a frame, anchored to a tiedown assembly, supporting a first pulley on a movable axis and a second pulley on a selectably fixed axis. A cable or chain extends over the first and second pulleys and is connected at one end to the frame, with the other end being attached to a workpiece. The pulleys are arranged in such a manner that movement of the first pulley away from the second pulley draws the end of the chain attached to the workpiece toward the second pulley. The movement of the first pulley is accomplished by selectively operable and controllable hydraulic power means. A third pulley may be mounted on the frame at various positions above the first and second pulleys for receiving the end of the chain attached to the workpiece, and maintaining the chain at various attitudes. Locking means hold the chain under tension to permit release of the hydraulic power means for sequential operation thereof. | 8 |
RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of U.S. patent application Ser. No. 13/590,377, filed Aug. 21, 2012, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to disposable, biodegradable items and more specifically to disposable items made from bioplastic resins.
[0003] Environment and sustainability have become increasingly important factors in the design and specification of medical and printing articles across the world. In hospitals, pharmaceuticals, life sciences, and healthcare industries, safe disposal of articles after use is an important issue. Special considerations are given to selecting materials in the final design for disposable articles, so as to reduce the quantity of medical and printing items that enter waste streams. These facilities and industries must initiate environmentally safe disposal methods because they generate a large amount of the biomedical and printing waste. Due to higher social responsibility and environmental concerns, corporations are being driven to produce more sustainable and environmentally safe products through government regulations, by institutional investors, and through consumer demand.
[0004] Bioplastic resins namely, polylactic acid (PLA), and polyhydroxyalkonate (PHA), are derived from a plant source, and are biodegradable.
[0005] Polylactic acid (PLA) is a transparent bioplastic produced from corn, beet and cane sugar. It not only resembles conventional petrochemical mass plastics, such as polyethylene (PE), polyethylene terephthalate (PET or PETE), and polypropylene (PP) in its characteristics, but it can also be processed easily on standard equipment that already exists for the production of conventional plastics. PLA has a density of 1.25 to 3 g cm, which is lower than PET, and PLA has a refractive index of 1.35-1.45, which is lower than PET, which has a refractive index of 1.54. PLA is currently used in biomedical applications, such as sutures, stents, dialysis media and drug delivery devices. It is also being evaluated as a material for tissue engineering.
[0006] The biopolymer poly-hydroxyalkonate (PHA) is a polyester produced by certain bacteria that process glucose or starch. PHA's characteristics are similar to those of the petro plastic polypropylene. The South American sugar industry, for example, has decided to expand PHA production to an industrial scale. PHA is distinguished primarily by its physical characteristics. It produces a transparent film at a melting point higher than 130 degrees Celsius, and is biodegradable without residue.
[0007] Poly3-hydoxybutrate-3-hydroxyhexxanate (PHBH) is a biodegradable resin. This co-polyester has been produced in a fermentation process using glucose and propionic acid as the carbon source for Alcaligenes eutrophus. It has mechanical and physical properties that vary based on the degree of co-polymerization. This bioplastic will undergo enzymatic biodegrading in the presence of microorganisms.
[0008] Embodiments of the present invention may utilize bioplastics that include: polylactic acid (PLA), polyhydroxyalkanoate (PHA), cellulose based (PH), Polybutyleneadipatetetephathalate (PBT), Polycaprolate (PCL), green polyethylene (GPE), and green polyethylene terephthalate (GPET or GPETE). PLA and PHA are derived by plant fermentation. PH is cellulose based. PBT and PCL are obtained from corn and cellulose. GPE and GPET/GPETE are obtained from sugarcane. PLA is especially compostable and can be degraded to make eco-friendly compost or humus.
[0009] Cross-linked polymers may have problems biodegrading, since the crosslinking forms strong bonds that are resist to enzymatic biodegradation in the presence of microorganisms. Plastics are durable but degrade very slowly; the molecular bonds that make plastic are durable, making it resistant to natural processes of degradation.
[0010] Bioplastic resins have some distinct advantages over plastic and glass. Bioplastic has a much smaller carbon footprint compared to plastic or glass, and also uses less energy to form an article like a syringe, multidose syringes, specimen tube, scalpels, lancets, and sharps containers, suction canisters and ink and toner cartridges, hereby referred to as disposable medical and printing articles, DMPA. Bioplastics are biodegradable in an industrial composting unit. Bioplastic resins are from a plant source, and when plants are grown, they absorb carbon dioxide, thus decreasing carbon dioxide in the atmosphere. Plastic and glass disposable items have a higher carbon footprint than bioplastic items. Current DMPA, when disposed of, enter the waste stream, and may need incineration in a process that causes release of hydrocarbons and toxins into the atmosphere and creates fly ash that ends up in landfills. Bioplastic articles bypass this process, and are therefore environmentally safe and sustainable, when compared to plastic or glass. Bioplastic, however, has poor permeability characteristics, in reference to water, oxygen and carbon dioxide. Bioplastic also has poor flexibility properties, and PLA has poor thermal properties, with heat distortion threshold of 55 Celsius, compared to plastics.
[0011] Used disposable syringes, multidose syringes, specimen tubes, and cartridges, scalpels and sharps containers, suction canisters may be referred to as disposable medical & printing articles (or DMPA). DMPA create a biomedical waste stream. Unfortunately, there are no easy, non-polluting methods that destroy used DMPA. Decontamination of DMPA removes pathogens from body secretions or blood, attached to them. However, once the sterile DMPA are shredded and placed in landfills, it will be contaminated by other germs. People who step on the needles will remain at risk for injury and other infections. The other least popular option that destroys the DMPA after disposal is incineration or burning. DMPA, made of polypropylene, cyclic olefin polymers or plastic material when incinerated or burned, cause release of hydrocarbon, carbon dioxide, carbon monoxide and airborne toxins, and is not environmentally safe.
[0012] Bioplastic or bioplastics are from a renewable source, and are sustainable for they have a small carbon footprint. Current plastic and glass DMPA, when disposed of, enters the medical waste stream and creates a negative environmental impact. DMPA during incineration causes release of hydrocarbons and toxins into the atmosphere and create fly ash that ends up in landfills. When DMPA made from bioplastic enters the biomedical waste stream it can be sterilized using steam, radiation (UV or gamma) or ethylene oxide gas, then shredded and placed in an industrial composting unit. This method is referred to as Bio medical and printing waste Sterilization and Composting Process, (or BSCP), which avoids incineration. The compost end product has few negative impacts on the environment. One can also opt to collect the sterile bioplastic shredded material to recycle and reclaim the resin. The whole process is cradle to cradle and uses less energy thereby offering a sustainable and environmentally safe method of manufacturing and disposing DMPA.
[0013] Diabetics and others frequently have to take a parental medication or an injection. They find themselves in situations where the assistance of a health care professional to administer the subcutaneous or intramuscular injection of a measured amount of a liquid agent is generally not available. In such situations such persons need to have a low cost multi dose syringe that does not require the assistance of a health professional to achieve the desired measure of accuracy. It may be the case that such persons require more than one dose per day, where each dose may require a different volume.
[0014] In hospitals, pharmaceuticals, life sciences and health industries, ever increasing attention is being paid to needle stick problems due to the contemporary sensitivity of exposure to AIDS, hepatitis, and other serious blood-borne diseases. This is prevented by the use of safety needle caps and shields.
[0015] Existing specimen tubes for storing blood are currently made commonly from plastics and glass, which are not sustainable or environmentally safe.
[0016] Lancets may be commonly used in the treatment of diabetes. The small blood samples obtained may be tested for blood glucose, hemoglobin, make blood smear slides, allergy skin tests and many other blood tests.
[0017] Existing sharps containers are filled with used medical needles or other sharp medical sharp instruments, such as suture needles, IV catheters and scalpels. They fit into two main types: single-use, which are disposed of with the waste inside the container, or multi-use, which are replaced by a new container periodically. It is standard practice for used needles and other sharps to be placed immediately into a sharps container after a single use, to prevent accidental needle sticks, which can lead to blood borne diseases including HIV and hepatitis. The emotional impact of needle stick and sharp injuries can be severe and long lasting, even when a serious infection is not transmitted. The sharps and needles are dropped into the container without touching the outside of the container. Proper use of a sharps container includes pickup by or delivery to an approved “red bag” or medical waste treatment site. In addition to this pre-existing safety measure, U.S. medical and educational staff is federally required to be tested on their knowledge of blood borne pathogens. During the last ten years, increased worldwide focus on safety and environmental impact has led to several positive government mandates being issued regarding engineered medical device standards and the reduction of clinical waste output from health facilities.
[0018] Suction canisters are extensively used in hospitals when it is necessary to create suction. In surgery, suction can be used to remove blood from the area being operated on to allow surgeons to view and work on the area. Suction may be used to clear the airway of blood, saliva, vomit, or other secretions so that a patient may breathe. Suctioning can prevent pulmonary aspiration, which can lead to lung infections. In pulmonary toilet, suction is used to remove fluids from the airways, to facilitate breathing and prevent growth of microorganisms. Suction devices may be mechanical hand pumps or battery or electrically operated mechanisms.
[0019] Current ink and toner cartridges are made from plastic material. An ink or inkjet cartridge is a replaceable component of a printer that contains the ink. Each ink cartridge contains one or more partitioned ink reservoirs; certain manufacturers also add electronic contacts and a chip that communicates with the printer. A toner cartridge, also called laser toner, is the consumable component of a laser printer or copy machine. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image on the paper. The toner is transferred to paper via an electro statically charged drum unit, and fused onto the paper by heated rollers during the printing process. Some toner cartridges incorporate the drum unit in the cartridge and therefore replacing the toner cartridge means replacing the drum unit.
[0020] Existing sharps and waste disposal containers may be made from petroleum-based plastics, such as polypropylene, with a biodegradable additive to degrade the polymer. Such plastics are not plant-based and are not bioplastics. An additive offers no ecological advantages. Oil-to-plastic processes release greenhouse gasses, while plant-to-bioplastic processes actually absorb CO2 out of the earth's atmosphere. A biodegradable resin such as PLA, PHA, or PHBA degrades on its own.
[0021] It would be desirable to provide bioplastic syringes with the needle caps and needle safety shields, multidose syringes, specimen tubes, scalpels, lancets, sharp disposal containers, suction canisters, printer and copy machine ink and toner cartridges, and methods for environmentally safe disposal of these items.
SUMMARY OF THE INVENTION
[0022] In one aspect of the present invention, a disposable device includes a biodegradable resin selected from the group consisting of polylactic' acid (PLA), cellulose based PH, polycaprolate (PCL), polybutyleneadipatetetephathalate (PBT), polyhydroxyalkanoate (PHA), green polyethylene (GPE), and green polyethylene terephthalate (GPET); a plasticizer intermixed with the resin to provide a generally homogenous bioplastic; and a device formed from the bioplastic, where the device is at least one of a multidose syringe, a sharps container, or a suction canister.
[0023] .In another aspect of the present invention, a syringe system includes a biodegradable resin that includes polylactic acid (PLA), and is substantially free from non-compostable material; a plasticizer intermixed with the resin to provide a generally homogenous and compostable bioplastic; a syringe that is formed from the bioplastic; and a green indicator on the syringe that indicates the syringe is substantially compostable.
[0024] In yet another aspect of the present invention, a method of disposing of an item includes providing an item made from a biodegradable resin and a plasticizer that are intermixed to provide a generally homogenous bioplastic; sterilizing the item; shredding the item; and composting the item into a compost end product, thereby disposing of the item.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 depicts an embodiment of a syringe with attached needle according to the present invention;
[0026] FIG. 2 depicts an embodiment of a general purpose syringe and assembly according to the present invention;
[0027] FIG. 3 depicts an embodiment of a multi dose syringe and assembly according to the present invention;
[0028] FIG. 4 depicts an embodiment of a safety needle cap and shield according to the present invention;
[0029] FIG. 5 depicts an embodiment of a specimen tube according to the present invention;
[0030] FIG. 6 depicts an embodiment of a scalpel handle and blade according to the present invention;
[0031] FIG. 7 depicts an embodiment of a lancet and cross section according to the present invention;
[0032] FIG. 8 depicts an embodiment of a sharps container according to the present invention;
[0033] FIG. 9 depicts an embodiment of a suction canister with a broad neck according to the present invention;
[0034] FIG. 10 depicts an embodiment of a suction canister with a narrow neck according to the present invention;
[0035] FIG. 11 depicts a perspective view an embodiment of a toner cartridge with drum according to the present invention;
[0036] FIG. 12 depicts a cross section of the embodiment of FIG. 11 ;
[0037] FIG. 13 depicts an embodiment of a ink cartridge with a single reservoir according to the present invention;
[0038] FIG. 14 depicts an embodiment of a ink cartridge with multiple reservoirs according to the present invention; and
[0039] FIG. 15 depicts an embodiment of a syringe system with green coloring to indicate the system is compostable.
DETAILED DESCRIPTION
[0040] The preferred embodiment and other embodiments, which can be used in industry and include the best mode now known of carrying out the invention, are hereby described in detail with reference to the drawings. Further embodiments, features and advantages will become apparent from the ensuing description, or may be learned without undue experimentation. The figures are not necessarily drawn to scale, except where otherwise indicated. The following description of embodiments, even if phrased in terms of “the invention” or what the embodiment “is,” is not to be taken in a limiting sense, but describes the manner and process of making and using the invention. The coverage of this patent will be described in the claims. The order in which steps are listed in the claims does not necessarily indicate that the steps must be performed in that order.
[0041] Embodiments of the present invention generally provide disposable syringes, multidose syringes, specimen tubes, scalpels, lancets, sharps containers, and suction canisters made from sustainable and environmentally safe bioplastic resins. Embodiments also provide ink and toner cartridges items from sustainable and environmentally safe bioplastic resins.
[0042] Embodiments of disposable plastic articles may be used in hospitals, pharmaceuticals, life sciences, and healthcare industries. Embodiments may be made from sustainable, environmentally friendly bioplastic resins and may be safely disposed without further environmental impact. Embodiments of disposable articles may be made from biodegradable resin, including polylactic polymer (PLA), polyhydroxyalkonate (PHA), or poly 3 hydroxybutrate co 3 hydroxyhexanote (PHBH). In an embodiment of the present invention, plasticizers may used to overcome permeability, stability, flexibility and thermal issues for these biodegradable resins.
[0043] Embodiments of bioplastics may be plant-based, from plants that were at least recently alive, rather than petroleum-based, which are from fossil fuels. A bioplastic or biodegradable resin is not the same as conventional plastic combined with further chemicals. No additive is needed to biodegrade embodiments of bioplastic products.
[0044] Embodiments of a multidose syringe may have a mechanism to control the amount of material delivered from a vial of medicine. Embodiments may have physical structure to give multiple correct dosages.
[0045] Embodiments of a disposable plastic syringe may be green-identified, to help users know that the item is “green” (compostable) and may be disposed of as a compostable item. A green PLA cap and needle shield may fit various sizes of compostable syringes, and may identify a syringe system as compostable. The components of a syringe system may be substantially free from non-compostable material in that, other than minor impurities, the component is entirely made of PLA and other non-compostable material. A multi-dose syringe may made substantially of PLA, and be identified with green labeling to identify the syringe as compostable.
[0046] Embodiments of a syringe system may include either a small syringe with green print, a large syringe with green print, a green needle cap, and/or a needle with green. The green color may indicate that the plastic component is “green” or compostable, such for example, from PLA. The needle may be metal or compostable material. Plastic elements in syringe system will be substantially compostable, but the metal needle might not be biodegradable. Methods for composting a compostable a syringe system or other item may include marking the item with green text or coloring, thereby indicating that the item is substantially compostable. The item or items can more easily be collected for appropriate disposal when the item is marked green as described (e.g. put in a green colored receptacle).
[0047] Cross-linked polymers may have problems biodegrading, since the cross-linking forms strong chemical bonds. Instead of cross-linking, embodiments of the present invention may have a low cross-linking density. The biodegradable resin and plasticizer may be mixed, extruded as a bioplastic, and will form thermal bonds without chemical curing. Embodiments may have no additives or agents for cross-linking so that the bioplastic will biodegrade, yet have sufficient stability and flexibility for disposable medical and printing articles. Instead, the resin and plasticizer are intermixed to provide a generally homogenous bioplastic that is formed to provide the disposable device. Such items can be sterilized using low-temperature methods such as radiation or ethylene oxide gas, to avoid melting the bioplastic.
[0048] FIG. 1 depicts an embodiment of a bioplastic syringe 10 with attached needle. Embodiments of bioplastic syringes may be used for insulin administration, allergy or tuberculin testing or administration of other parental agents. An embodiment of a syringe 10 may be made from bioplastic, and may have a simple piston pump with a plunger that fits tightly in a tube. The plunger may be pulled and pushed along inside a cylindrical tube (the barrel), allowing the syringe to take in and expel a liquid or gas through an orifice at the open end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle, or tubing to help direct the flow into and out of the barrel. Embodiments of bioplastic syringes may be used in the medical field to administer injections, insulin administration, skin tests such as allergy tests, and tuberculin testing. In non-medical field uses, non-sterile bioplastic syringes may be used to apply compounds such as glue or lubricant, and measure liquids.
[0049] FIG. 2 depicts perspective and in cross section views of a general propose disposable single-use syringe 10 that may have a plunger 12 with a rubber tip 14 , a cylindrical barrel 16 , a hypodermic needle 18 and a needle cap 20 . Plunger 12 , barrel 16 and needle cap 20 may include or be made from bioplastic resin.
[0050] FIG. 3 depicts an embodiment of a multidose syringe assembly 30 or dispenser that may have a pen cap 32 , a needle cap 34 , a housing cylinder 36 , a collar 40 , and collar assembly 42 , cylinder tube 44 , piston plunger 46 and a numerically calibrated cap 48 , all of which may include or be made from bioplastic resin. Housing cylinder 36 holds a prefilled vial 38 that contains fluid. An embodiment of a syringe assembly 30 or dispenser may have the general appearance of a pen. A pen-like dispenser may be large enough to hold several doses, yet be small enough to fit conveniently in a user's pocket or purse, such as, for example, from 5½ “ long to 7” long, An embodiment of a pen-like dispenser may include several parts all made from bioplastic, perhaps other than a prefilled vial that holds the liquid agent.
[0051] FIG. 4 depicts an embodiment of a safety needle cap and shield assembly 50 , which may include a needle cap 52 and a needle safety shield 54 attached to the syringe cylindrical barrel 16 , all of which may include or be made from bioplastic resin. An embodiment of a syringe needle assembly may include a syringe fixed to a medical or hypodermic needle. An embodiment of a bioplastic cap and a safety shield assembly 50 may attach to the syringe needle assembly, to help provide protection from a sharpened tip of the needle. The cap 52 may be removed before using the syringe needle assembly. After using the syringe needle assembly, the safety shield 54 may be deployed. The safety shield 54 may be foldable or may include a tubular assembly, thereby providing a safety sheath for the needle. This may help guard against problems associated with inadvertent needle sticks related to blood sampling, percutaneous medication injection and other medical procedures involving uses of medical needles.
[0052] FIG. 5 depicts an embodiment of a blood specimen tube 60 . The tube 60 may have walls 62 adapted to contain blood, which may include a bioplastic resin.
[0053] FIG. 6 depicts an embodiment of a scalpel 70 , which may include a blade 72 in a retractable safety handle 74 . Handle 74 may include a bioplastic resin. An embodiment of a scalpel may be a small and extremely sharp bladed instrument used for surgery, anatomical dissection, and various arts and crafts. Embodiments of scalpels may be disposable and single-use, with a safety retractable blade that can be refracted and extended in and out of a bioplastic handle.
[0054] FIG. 7 depicts an embodiment of a lancet 80 , which may include a safety cap 82 , a needle with a piercing tip 84 , and a body 86 . Safety cap 82 and body 86 may include bioplastic resin. An embodiment of a disposable lancet 80 may be used to make punctures to obtain small blood specimens. An embodiment of a lancing device may be a reusable instrument equipped with a bioplastic lancet 80 .
[0055] FIG. 8 depicts an embodiment of a sharps container 90 , which may include or be made from bioplastic resin.
[0056] FIG. 9 depicts an embodiment of a broad neck suction canister assembly 100 with a cap 102 and broad neck receptacle 104 . FIG. 10 depicts an embodiment of a narrow neck suction canister assembly 106 with a cap 108 and narrow neck receptacle 110 . The caps 102 , 108 and receptacles 104 , 110 may include or be made from bioplastic resin.
[0057] FIGS. 11 and 12 depict an embodiment of a toner cartridge 120 . Toner cartridge 120 may include a first casing part 122 and a second casing part 124 , which are separable from each other. First casing part 122 may have a photosensitive drum 126 that retains an electrostatic latent image on its surface and a waste toner unit 128 that removes and collects toner remaining on the surface of photosensitive drum 126 . Second casing part 124 may have a toner hopper 130 that contains toner 134 , a magnet roller 136 that supplies toner from toner hopper 130 to photosensitive drum 126 , and which develops the electrostatic latent image and charging roller 138 that uniformly charges the surface of photosensitive drum 126 . Toner cartridge 120 may be assembled from first part 122 and second part 124 . Toner cartridge 120 , first casing part 122 , and second casing part 124 may include or be made from bioplastic resin.
[0058] FIG. 13 depicts an embodiment of an ink cartridge with a single reservoir 140 . FIG. 14 depicts an embodiment of an ink cartridge with multiple reservoirs 142 . Embodiments of bioplastic ink and toner reservoirs may be used in printer and copy machines. Ink reservoirs 140 and 142 may include or be made from bioplastic resin and may be attached to a base that can include electronic, plastic, or bioplastic parts or materials.
[0059] As depicted in FIG. 15 , an embodiment of a compostable or “green” syringe system 150 may include one or more of a compostable small syringe 152 with green print 154 , a compostable large syringe 156 with green print 158 , a compostable green needle cap 160 with green coloring 162 , or a safety needle 164 with compostable green plastic base.
[0060] The embodiments described are not intended to be limited to the pictured shapes, sizes and orientations. | Disposable items made from bioplastic resins include a biodegradable resin selected from the group consisting of polylactic acid (PLA), cellulose based PH, polycaprolate (PCL), polybutyleneadipatetetephathalate (PBT), polyhydroxyalkanoate (PHA), green polyethylene (GPE), and green polyethylene terephthalate (GPET); a plasticizer intermixed with the resin to provide a generally homogenous bioplastic; and a device formed from the bioplastic, where the device is at least one of a multidose syringe, a sharps container, or a suction canister. A method of disposing of an item includes providing an item made from a biodegradable resin and a plasticizer that are intermixed to provide a generally homogenous bioplastic; sterilizing the item; shredding the item; and composting the item into a compost end product, thereby disposing of the item. | 2 |
TECHNICAL FIELD OF THE INVENTION
The present invention pertains in general to clock circuits and, more particularly, to a clock circuit with a fractional divide functionality to provide an output clock that is divided by a non-integer value.
CROSS REFERENCE TO RELATED APPLICATIONS
N/A
BACKGROUND OF THE INVENTION
In order to achieve a relatively high frequency operation for an integrated circuit, there will be provided on that integrated circuit clock circuitry. This clock circuitry will operate at some base reference frequency that is typically defined by a crystal time base. However, to obtain higher operating speeds, higher clock frequencies are required than are provided with the base timing circuitry. To facilitate this, clock multipliers are utilized. For example, there are situations where certain circuitry on the integrated circuit is not capable of operating at the integer multiplication factor. This is due to the fact that there is some component on a functional block on the circuit that, due to processing limitations, etc., do not allow the overall integrated circuit to function at the highest clock operating speed, although the clock portion of the integrated circuit can operate at that frequency. However, there may be a maximum operating speed or frequency at which the functional circuitry will operate that is not an integer multiplication factor of the base timing of the clock. Rather than redesign the multiplier circuit, the full multiplication of the clock is performed and then a fractional divide is made to that maximized clock frequency. For example, if a base timing clock circuit operated on a crystal and provided a 25 MHz base clock, which was then multiplied to 100 MHz by a 4× multiplier, it may be that the functional circuitry or processing circuitry associated with the rest of the integrated circuit can only operate at ⅔ of the 100 MHz operating frequency or 66.67 MHz. Therefore, a fractional divide circuit of ⅔ would be required.
SUMMARY OF THE INVENTION
The present invention disclosed and claimed herein, in one aspect thereof, comprises a fractional divide circuit for generating a periodic fractional clock. A base clock is provided for generating a pre-divide clock at a base clock frequency with a period counter provided for counting cycles of the base clock. A select register stores constants that define parameters for a fractional divide ratio, there being at least four. A positive edge flip flop is provided wherein two of the constants are associated therewith. A negative edge flip flop is provided wherein the other of the two constants are associated therewith. A matching device is operable for setting on the positive edge of the base clock the first flip flop when the first of the two associated constants matches the output of the period counter and clearing the first flip flop when the other of the two associated constants matches the output of the period counter, and setting on the negative edge of the base clock the second flip flop when the first of the two associated constants matches the output of the period counter and clearing the second flip flop when the other of the two associated constants matches the output of the period counter. The outputs of the second and first flip flops are ANDed to provide the fractional clock output.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:
FIG. 1 illustrates an overall diagram view of an MCU with a separate low power real time clock (RTC);
FIG. 2 illustrates an overall block diagram of the MCU chip showing the various functional blocks thereof;
FIG. 3 illustrates a block diagram of the oscillators utilized for the processing operation of the MCU;
FIG. 4 illustrates a block diagram of the RTC;
FIG. 5 illustrates a logic diagram for the overall fractional clock circuit;
FIG. 6 illustrates a logic diagram for the period counter;
FIG. 7 illustrates a table depicting the state machine operation for determining load values for the period counter and the relationship to the positive edge and negative edge table;
FIG. 8 illustrates a flow chart for the operation of determining the load value from the value in the select register;
FIG. 9 illustrates a table for the counter values;
FIG. 10 illustrates a flow chart for the operation of the period counter;
FIG. 11 illustrates a table depicting the sequence of the counter as a function of the value in the select register; and
FIG. 12 illustrates a timing diagram for the operation of the clock logic diagram of FIG. 5 .
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1 , there is illustrated a block diagram of a processor-based system that drives the mixed signal technologies that include as a part thereof, a digital section including a central processing unit (CPU) 102 and a digital I/O section 104 that is operable to interface with various serial inputs and outputs. The system also includes the analog section which provides for an analog-to-digital converter (ADC) 106 that is operable to receive one or more analog inputs and also provides a digital-to-analog converter 110 for allowing digital information from the CPU 102 to be converted to analog output information. The operation of the CPU 102 is controlled by various clocks 112 in a primary oscillator section. These are the operational clocks that control the overall operation of the MCU. In one mode, they will be interfaced with a crystal 114 for precision operation thereof However, as will be described herein below, a precision internal non-crystal based clock can be utilized and, further, there can be a high frequency crystal and a low frequency crystal for two different operational modes. Normally, the output of the block 112 provides the operating clock with the CPU 102 .
There is also provided a separate stand alone real time clock (RTC) block 116 . This clock 116 operates on a separate RTC crystal 118 that provides the time base therefor. The RTC 116 interfaces with the chip supply voltage V DD , which also drives CPU 102 and the clock block 112 . The RTC block 116 interfaces with a battery terminal 120 and an external back-up battery 122 . The RTC 116 has disposed thereon a plurality of registers 124 , which are operable to store the timing information associated with the RTC 116 . The RTC 116 operates independently with the primary purpose being to maintain current time and date information therein separate and independent of the operation of the digital and analog sections and the power required thereby or provided thereto. This information can be initialized by the CPU 102 through a digital interface 130 with the registers 124 . During operation, the RTC 116 will update its internal time and date information, which information is stored in the registers 124 . The RTC 116 is operable to generate an interrupt on an interrupt line 132 (to the CPU 102 ). Therefore, the RTC 116 can interface with the CPU 102 in order to generate an interrupt thereto. As will be described herein below, this interrupt facilitates waking the CPU 102 up when it is placed into an inactive or deep sleep mode. However, the CPU 102 at any time can query the register 124 for information stored therein. The RTC 116 , as will also be described herein below, is a very low power circuit that draws very little current, the current on the order of 600 nA.
Referring now to FIG. 2 , there is illustrated a block diagram of the MCU 102 . As noted herein above, this is a conventional operation of, for example, a part number C8051F330/1 manufactured by Silicon Laboratories Inc. The MCU 102 includes in the center thereof a processing core 202 which is typically comprised of a conventional microprocessor of the type “8051.” The processing core 402 receives a clock signal on a line 204 from a multiplexer 206 . The multiplexer 206 is operable to select among multiple clocks. There is provided an 80 kHz internal oscillator 208 , a 24.5 MHz trimmable internal precision oscillator 212 or an external crystal controlled oscillator 210 . The precision internal oscillator 212 is described in U.S. patent application Ser. No. 10/244,344, entitled “PRECISION OSCILLATOR FOR AN ASYNCHRONOUS TRANSMISSION SYSTEM,” filed Sep. 16, 2002, which is incorporated herein by reference. The processing core 202 is also operable to receive an external reset on terminal 213 or is operable to receive the reset signal from a power-on-reset block 214 , all of which provide a reset to processing core 202 . This will comprise one of the trigger operations. The processing core 202 has associated therewith a plurality of memory resources, those being either flash memory 216 , SRAM memory 218 or random access memory 220 . The processing core 202 interfaces with various digital circuitry through an on-board digital bus 222 which allows the processing core 202 to interface with various operating pins 226 that can interface external to the chip to receive digital values, output digital values, receive analog values or output analog values. Various digital I/O circuitry are provided, these being latch circuitry 230 , serial port interface circuitry, such as a UART 232 , an SPI circuit 234 or an SMBus interface circuit 236 . Three timers 238 are provided in addition to another latch circuit 240 . All of this circuitry 230 - 240 is interfacable to the output pins 226 through a crossbar device 242 , which is operable to configurably interface these devices with select ones of the outputs. The digital input/outputs can also be interfaced to a digital-to-analog converter 244 for allowing a digital output to be converted to an analog output, or to the digital output of an analog-to-digital converter 246 that receives analog input signals from an analog multiplexer 248 interfaced to a plurality of the input pins on the integrated circuit. The analog multiplexer 248 allows for multiple outputs to be sensed through the pins 226 such that the ADC can be interfaced to various sensors. Again, the MCU 102 is a conventional circuit.
Referring now to FIG. 3 , there is illustrated a schematic diagram of the primary oscillator section comprised of the oscillators 210 and 212 and the multiplexer 206 . The oscillator 210 is a crystal controlled oscillator that is interfaced through two external terminals 302 and 304 to an external crystal 306 and operates up to frequencies in excess of 25 MHz. A register 308 is provided, labeled OSCXCN, which is operable to drive control signals for the oscillator 210 and to record output values thereof. The output of the oscillator 210 is provided on a line 310 to one input of the multiplexer 206 (equivalent to multiplexer 142 in FIG. 1 ). The programmable precision trimmable oscillator 212 is controlled by a register 318 and a register 320 to control the operation thereof, i.e., to both set the frequency thereof and to enable this oscillator. The output of the oscillator 212 is processed through a divide circuit 330 , the divide ratio thereof set by bits in the register 320 to provide on an output 322 a precision high frequency clock to another input of the multiplexer 206 . The output of the multiplexer 206 is provided to the MCU 102 on the clock line 404 as a system clock signal SYSCLK. The clock select operation is facilitated with a register 324 labeled CLKSEL, which controls the multiplexer 206 .
The programmable high frequency oscillator 212 is the default clock for system operation after a system reset. The values in the register 318 , labeled OSCICL, provide bits that are typically programmed at the factory, these bits stored in the flash memory. The center frequency of the high frequency clock is 24.5 MHz. The divide circuit 330 can provide a divide ratio of one, two, four or eight. The oscillator 212 , in the C8051F330 device by way of example only, is a ±2 percent accuracy oscillator which has a center frequency that, although programmed at the factory, is allowed to be adjusted by changing the bits in the register 318 . There are provided seven bits in the register 318 that are calibratable bits. The register 320 provides an enable bit for the oscillator 212 and a bit that determines if the oscillator 212 is running at the programmed frequency. Two bits in the register 320 are utilized to set the divide ratio of the divider 330 .
There is also provided a clock multiplier circuit 350 , which is comprised of a multiplexer 352 for selecting the output of the clock circuits 210 , the internal clock 212 or the clock 210 divided by a factor of 2 and providing the selected clock to a 4× multiplier 378 . This multiplied clock is then input to a fractional divide block 380 , the output thereof selected by the multiplexer 206 . This block 350 is controlled by a select register 360 . The select register operates in accordance with the following table:
TABLE 1
CLKMUL: Clock Multiplier Control Register
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
MULEN
MULINIT
MULRDY
MULDIV
MULSEL
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7 : MULEN: Clock Multiplier Enable
0: Clock Multiplier disabled. 1: Clock Multiplier enabled.
Bit 6 : MULINIT: Clock Multiplier Initialize
This bit should be a ‘0’ when the Clock Multiplier is enabled. Once enabled, writing a ‘1’ to this bit will initialize the Clock Multiplier. The MULRDY bit reads ‘1’ when the Clock Multiplier is stabilized.
Bit 5 : MULRDY: Clock Multiplier Ready
This read-only bit indicates the status of the Clock Multiplier. 0: Clock Multiplier not ready. 1: Clock Multiplier ready (locked).
Bits 4 - 2 : MULDIV: Clock Multiplier Output Scaling Factor
These bits scale the Clock Multiplier output. 000: Clock Multiplier Output scaled by a factor of 1. 001: Clock Multiplier Output scaled by a factor of 1. 010: Clock Multiplier Output scaled by a factor of 1. 011: Clock Multiplier Output scaled by a factor of ⅔. 100: Clock Multiplier Output scaled by a factor of 2/4 (or ½). 101: Clock Multiplier Output scaled by a factor of ⅖. 110: Clock Multiplier Output scaled by a factor of 2/6 (or ⅓). 111: Clock Multiplier Output scaled by a factor of 2/7.
Bits 1 - 0 : MULSEL: Clock Multiplier Input Select
These bits select the clock supplied to the Clock Multiplier.
Clock Multiplier Output MULSEL Selected Input Clock for MULDIV = 000b 0 Internal Oscillator/2 Internal Oscillator × 2 1 External Oscillator External Oscillator × 4 10 External Oscillator/2 External Oscillator × 2 11 Internal Oscillator Internal Oscillator × 4
It can be seen that bits 4 - 2 set the divide ratio for the fractional divide circuit. For values “000,” “001” and “010,” there will be no fractional divide. For the remaining values, there will be a non integer divide.
Referring now to FIG. 4 , there is illustrated a detailed block diagram of the low power RTC 116 . There is provided a dedicated RTC oscillator 402 that is operable at 32 kHz oscillator frequency, which can be utilized with or without a crystal. There are provided two external pads 404 and 406 for interfacing with the crystal in a crystal-based mode or they can be connected together in a non-crystal based mode. Then the RTC 116 receives the back-up battery input on the node 120 and supply voltage V DD on a V DD pin 408 . A 48-bit timer 410 is provided which is clocked by the RTC oscillator 402 . An RTC state machine 412 controls the operation of the RTC 116 and is operable to interface with the 48-bit timer 410 to write data therein or read data therefrom and in general control the configuration thereof. As will be described herein below, the 48-bit timer includes a counter, latches and an alarm function. The RTC state machine 412 is operable to generate the interrupt on the line 132 , when necessary, and is interfaced with an RTC internal bus 414 . The internal bus 414 is operable to interface with a back-up RAM 416 , which is typically configured with static RAM (SRAM) with a storage capacity of 64 bytes. Storage is provided by internal registers 418 which provide an internal storage for the data captured from the 48-bit timer 410 and various addressing data that is transferred between the RTC state machine 412 and the CPU 102 . There is provided an interface register 420 that allows the CPU 102 an interface path to the internal registers 418 . There is provided power control with a switch over logic block 424 , which is operable to monitor the voltage level of V DD and, if it falls below a predetermined level, it will switch over to a back-up battery on the input terminal 120 (noting that the voltage V DD can be provided by a primary battery). There is provided a regulator circuit 428 that regulates the bach-up battery or the supply voltage to the appropriate level, if necessary.
When utilized with a crystal, operating at a frequency of 32.768 kHz watch crystal and a back-up power supply of at least 1V, the RTC 116 allows a maximum of 437 years of time keeping capability with 47-bit operation or 272 years with 48-bit resolution. This is independent of the operation of the overall MCU. Although not shown, the RTC state machine 412 also includes a missing clock detector that can interrupt the processor and the oscillators 118 from the suspend mode, or even generate a device reset when the alarm reaches a predetermined value.
The interface registers 420 include three registers, RTC0KEY, RTC0ADR, and RTC0DAT. These interface registers occupy a portion of the special function register (SFR) memory map of the CPU 102 and provide access to the internal registers 418 of the RTC 116 . The operation of these internal registers is listed in the following Table 2. The RTC internal registers 418 can only be accessed indirectly through the interface registers 420 .
TABLE 2
RTC0 Internal Registers
RTC
RTC
Address
Register
Register Name
Description
0x00-
CAPTUREn
RTC Capture Registers
Six Registers used for
0x05
setting the 48-bit RTC
timer or reading is
current value.
0x06
RTC0CN
RTC Control
Controls the operation of
Register
the RTC State Machine.
0x07
RTC0XCN
RTC Oscillator
Controls the operation of
Control Register
the RTC Oscillator.
0x08-
ALARMn
RTC Alarm Registers
Six registers used to set
0x0D
the 48-bit RTC
alarm value.
0x0E
RAMADDR
RTC Backup RAM
Used as an index to the
Indirect Address
64 byte RTC backup
Register
RAM.
0x0F
RAMDATA
RTC Backup RAM
Used to read or write the
Indirect Data Register
byte pointed to
by RAMADDR.
The RTC interface register RTC0KEY is a lock and key register that is operable to protect the interface 420 . This register must be written with the correct key codes, in sequence, by the CPU 102 before Writes and Reads to the internal address register RTC0ADR and the internal data register RTC0DAT of the internal registers 418 . This provides an address for the internal back-up RAM and data for being stored thereat for a Write and provides an address for a Read with a subsequent Write to the RTC0DAT register by the RTC 116 followed by a subsequent Read of that RTC0DAT register by the CPU 102 . The key codes are 0xa5, 0xf1. There are no timing restrictions, but the key codes must be written in order. If the key codes are written out of order, the wrong codes are written, or an invalid Read or Write is attempted, further Writes and Reads to RTC0ADR and RTC0DAT will be disabled until the next system reset. Reading of the RTC0KEY register at any time will provide to the interface status of the RTC 116 , but does not interfere with the sequence that is being written. The RTC0KEY register is an 8-bit register that provides four status conditions. The first is a block status, indicating that the two key codes must be sequentially written thereto. After the first key code is written, the status will change to the next status indicating that it is still locked, but that the first key code has been written and is waiting for the second key. The next status is wherein the interface is unlocked, since the first and second key codes have been written in sequence. The fourth status indicates that the interface is disabled until the next system reset. The RTC0KEY register is located at the SFR address 0xAE and, when writing thereto, the first key code 0xA 5 is written followed by the second key code 0xF1, which unlocks the RTC interface. When the state indicates that it is unlocked, then any Write to the RTC0KEY register will lock the RTC0 interface.
The RTC internal registers 418 can be read and written using the RTC0ADR and RTC0DAT interface registers. The RTC0ADR register selects the particular RTC internal register that will be targeted by subsequent Reads/Writes to RTC0DAT. Prior to each Read or Write, the RTC interface Busy bit, bit 7 therein, should be checked to make sure the RTC interface is not busy performing another Read or Write operation. An example of an RTC Write to an internal register would involve a Wait operation when the Busy bit indicates it is busy. Thereafter, the RTC0ADR bit would be written with the value of, for example, 0x06, which would correspond to an internal RTC address of 0x06. This will be followed by a Write of a value of, for example, 0x00 to RTC0DAT which will Write the value 0x00 to the RTC0CN internal register (associated with the internal 0x06 address), which RTC0CN register is the RTC control register. There are generally in this embodiment, sixteen 8-bit internal registers. There are six internal registers for the captured data from the timer 410 , one register for the RTC0CN control information, six alarm registers, and a back-up RAM address register and a back-up RAM data register. By first writing the control information to RTC0CN, this can be followed by writing or reading data from any of the other internal registers. To write to the register, the RTC0CN internal register has the Busy bit written thereto in order to initiate an indirect Read by the CPU 102 . Once the Read is performed by the CPU 102 , then the contents of RTC0DAT are loaded with the contents of RTC0CN. The system can be set such that there will be a sequence of indirect Reads by setting the appropriate bit in the control register. These will be provided with a series of consecutive Reads such that, for example, the contents of either the capture registers or the alarm registers can be completely read out. The RTC0ADR register will automatically increment after each Read or Write to a capture or alarm register. The RTC0CN register is an 8-bit register and has an enable bit, a missing clock detector enable bit, a clock fail flag bit, a timer run control bit indicating that the timer either holds its current value or increments every RTC clock period, an alarm enable bit that is operable to enable the alarm function, a set bit that causes the value in the timer registers, the capture registers, to be transferred to the RTC timer for initialization purposes and the capture bit that causes the contents of the 48-bit RTC timer to be transferred to the capture registers. There is also provided an oscillator control register, RTC0XCN, which is an 8-bit register providing for gain control of the crystal oscillator, a mode select bit for selecting whether the RTC will be used with or without a crystal, a bias control bit that will enable current doubling, a clock valid bit that indicates when the crystal oscillator is nearly stable and a V BAT indicator bit. When this is set, it indicates that the RTC is powered from the battery.
The RTC timer 410 is, as described herein above, a 48-bit counter that is incremented every RTC clock, when enabled for that mode. The timer has an alarm function associated therewith that can be set to generate an interrupt, reset the entire chip, or release the internal oscillator in block 112 from a suspend mode at a specific time. The internal value of the 48-bit timer can be preset by storing a set time and date value in the capture internal registers and then transferring this information to the timer 410 . The alarm function compares the 48-bit value in the timer on a real time basis to the value in the internal alarm registers. An alarm event will be triggered if the two values match. If the RTC interrupt is enabled, the CPU 102 will vector to the interrupt service routine when an alarm event occurs. If the RTC operation is enabled as a reset source, the MCU will be reset when an alarm event occurs. Also, the internal oscillator 112 will be awakened from suspend mode, if in that mode, on an RTC alarm event.
Referring now to FIG. 5 , there is illustrated a logic block diagram of the fractional divide circuit 380 , which is clocked by the pre-divide clock circuit. If the multiplier 378 was a 4× counter with a 25 MHz clock, then the pre-divide clock would have a frequency of 100 MHz. This is input on a node 502 . The select register 360 is operable to provide a 3-bit output value from “000” through “111.” As noted herein above, the first three values, “000,” “001” and “010” will select the pre-divide clock and the others will select fractional divide clocks. The select register output is utilized for the values of “011” and above to drive a period counter 504 . This will provide a count output on a line 506 . The period counter 504 is a state counter, wherein the load value of a counter is dependent upon the last state, on the output thereof. This will be described in more detail herein below. There are provided four constants, two for setting a positive edge flip-flop 508 and two for setting a negative edge flip-flop 510 . The two constants that are associated with the positive edge flip-flop 508 are the PE_LOW and PE_HIGH.
Each of the flip-flops 508 and 510 are clocked by the high frequency pre-divide clock on line 502 , it being noted that the flip-flop 510 is clocked with the inverted pre-divide clock. In order to determine what the data state is on the input to the flip-flop 508 , a state machine determines what the level of the clock is, i.e., “high” or “low,” the state of the clock relative to the two constants PE_LOW and PE_HIGH. For this portion of the state machine, the flip-flop 508 has a data input thereof connected to the output of an ordered multiplexer 514 . The multiplexer 514 has three inputs. The state machine operates such that the decision made with respect to the first input, if it is true, results in selection of that fixed input, a “1,” for output therefrom. If false, then the decision associated with the second input is assessed and, if true, then that fixed input, a “0,” is output as the input to the flip-flop 508 . If neither of the decisions for the first and second input is true, then the third input is connected to the Q-output of the flip-flop 508 . The first decision is a decision wherein the value of PE_HIGH associated with the particular 3-bit output of the select register 360 is compared to the count value of the period counter. Each of the potential 3-bit values above “010” stored in the select register 360 has associated therewith fixed values for PE_LOW, PE_HIGH, NE_LOW and NE_HIGH. If the corresponding value of PE_HIGH is determined to be equal to the output of the counter with an equality block 516 , then a “1” is input to the first input of multiplexer 514 , i.e., the highest priority one thereof. If the equality is not true, then the select input multiplexer 514 will evaluate the decision associated with the next input. The decision associated with the next input, the next priority input, will have a decision made as to whether the output of the counter 504 on line 506 is equal to the fixed value of PE_LOW associated with the of the select register 360 , decided in an equality block 518 . If so, a “0” is selected by the multiplexer 514 for output to the data input of the flip-flop 508 . If this is a false decision, then the output of the multiplexer 514 is connected to the output of the flip-flop 508 . Therefore, the multiplexer 514 will either force a “1” to the data input of the flip-flop 508 , a “0” or the last state, depending upon the comparison of the output value of the counter 504 with either PE_HIGH or PE_LOW. The Q-output of the flip-flop 508 is input to one input of an AND gate 520 .
The decisions made with respect to flip-flop 51 are similar to that associated with flip-flop block 508 . In this block, there is provided a multiplexer 524 that provides data to the data-input of the flip-flop 510 . The first input is associated with a decision wherein the constant NE_HIGH is compared with the output of a counter 504 and, if it is determined to be equal by an equality block 526 , then a “1” is output from the multiplexer 524 . If this is determined to be false, then the decision associated with the next input is determined. This is a decision wherein the fixed value of NE_LOW associated with the output of the select register 360 is compared to the output of the counter 504 with an equality block 528 and, if true, then a “0” on the second input of multiplexer 524 is connected to the output thereof. If neither decision associated with the equality block 526 or 528 were true, then the third input of the multiplexer 524 is connected to the Q-output of the flip-flop 510 such that the last state is forced as an input thereto. The Q-output of the flip-flop 510 is input to the other input of the AND gate 520 . The output of the AND gate 520 is input to one input of the multiplexer 532 , which is operable to select either the output of the AND gate 520 , this being the fractional divide clock, or select the pre-divide clock on the node 502 . The output of multiplexer 532 provides the clock output. The multiplexer 532 is operable to select the node 502 whenever the output of the select register 360 is either “000,” “001” or “010.” These three inputs are input to a 3-input OR gate 536 , the output thereof providing the select input to multiplexer 532 .
Referring now to FIG. 6 , there is illustrated a block diagram of the period counter 504 . The period counter 504 is a 3-bit counter that is comprised of a 3-bit state counter which has associated therewith three flip-flops 602 , 604 and 606 associated with the data output values, D 0 , D 1 and D 2 , respectively. These are provided on the Q-outputs thereof. The data inputs thereto are connected to the data input bits B 0 , B 1 and B 2 , respectively. The clock inputs of the flip-flops 602 - 606 are connected to the pre-divide clock on the line 502 .
The flip-flops 602 - 604 have the input state thereof determined by a state machine 610 , which is operable to perform a lookup and determine the data input value for the bits B 0 , B 1 and B 2 . This is either a predetermined state obtained from a lookup table or the last state thereof either decremented or incremented. The state machine 610 , as will be described herein below, has access to the contents of the select register 360 and also to a PE/NE table 614 .
Referring now to FIG. 7 , there is illustrated a table depicting the relationship between the value in the select register 360 , the initial counter load value and the PE/NE table 614 . The state machine 610 operates a counter by determining what the value in the select register 360 is and then determining what the initial load value is in order to determine the counter sequence. As noted herein above, for values in the select register 360 between 0-2, the period counter will not be required, since the output of the pre-divide clock is selected. However, once the value is equal to a value from 3-7, then the fractional divide will operate. There are provided two columns, one for the select register 360 output and one for the counter load value for the bits B 0 , B 1 and B 2 . In general, the counter load value is determined by examining the value of S 0 in the select register 360 and then, if it is a “1,” outputting the value of the select register as the values of B 0 , B 1 and B 2 , i.e., a direct correspondence therewith, or, if the value is a “0,” then shifting to the right by substituting B 0 with the S 1 value, B 1 with the S 2 value and B 2 with “0.”
The illustration of determining the counter load value is set forth in the flow chart of FIG. 8 . This is initiated at a block 802 and then flows to a decision block 804 to determine if the value of the select register is greater than or equal to “3.” If so, the program flows along the “Y” path to a decision block 806 to determine if the value of B 0 is equal to 1. If so, the program flows along the “Y” path to a function block 808 to set the load value equal to that in the select register 360 and then proceeds to an End block 810 . If the value of B 0 was determined not to be equal to “1” in the decision block 806 , the program flows along the “N” path to a function block 812 to make the substitution of B 0 to S 1 , B 1 to S 2 and B 2 to “0.” The program then flows to the End block 810 .
Referring now to FIG. 9 , the operation of the counter will be described. In general, the state machine 610 operates the counter as a decrementing counter. The initial load value, as determined by the flow chart of FIG. 8 will be loaded in to the counter. There will also be an overflow value, “OV,” that is associated with each value of the counter. The value of OV for count values of “2” through “7” will be set to “0.” For the value of “0” or “1” of the counter output, the overflow value is set to “1.” Once the counter is initialized at the load value, the counter will decrement until it is determined that the current state has an overflow value of “1” which will then result in the next value being the counter load value. In this embodiment, for a select register output of “011” associated with the value “3,” there will be a counter load value of “011.” This will result in the value of “011” being the initial value of the counter and then it will decrement to “010” with an overflow value of “0,” which will then result in the counter being further decremented to the value of “001.” The overflow value for “01” is “1,” such that the next state will be the counter load value of “011.” Thus, the counter will sequence from 3, 2, 1 over to 3, 2, 1, and so on. This, of course, is dependent upon the counter load value as set forth herein above with respect to the table in FIG. 7 .
Referring now to FIG. 10 , there is illustrated a flow chart depicting the operation of the period counter 504 . This is initiated at a block 1002 and then proceeds to a block 1004 to initialize the counter with a load to value. The initial value will be the load value form the table of FIG. 7 that his determined by the flow chart of FIG. 8 . This will be loaded as a load value in function block 1006 . The program then flows to a function block 1008 to clock this through to the output and then proceeds to a decision block 1010 to determine if the overflow value of the current state is “1.” If so, this indicates the end of the count and the program flows along the “Y” path back to the input of the function block 1006 to again load the load value determined by the flow chart of FIG. 8 . If the overflow value is not equal to “1,” then the program proceeds along the “N” path to a function block 1012 in order to decrement the output value by “1” and then provide this as the load value, i.e., this is a decremented counter. The program then flows back to the input of function block 1008 to again clock through the value to continue the count.
Referring now to FIG. 11 , there is illustrated a table depicting the counter sequence for a given value of the select register. As noted herein above, until the value equals “011” associated with the value of “3,” there will be no sequencing of the counter. For the value of “011,” the sequence will then be “321321. . .” for the remaining values of “4” through “7” there are illustrated the sequence of values that are output, each of these output values represented by a 3-bit count output. This is the output of the flip-flops 602 , 604 and 606 .
Referring now to FIG. 12 , there is illustrated a timing diagram depicting the operation of the embodiment of FIG. 5 . The pre-divide clock which is labeled CLKOUT PREDIV is set forth and the example herein will be that for the select register value of “011” which will have a sequence of “321321321321. . .” To evaluate this, it can be seen from the table of FIG. 7 that PE_HIGH is a “1” and PE_LOW is a “2,” NE_HIGH is a “2” and NE_LOW is a “3.” These are fixed values, i.e., the “constants,” for that select register value. For simplicity sake, there are provided four states for the results of the equality blocks 516 , 518 , 526 and 528 , associated with the constants PE_HIGH, PE_LOW, NE_HIGH and NE_LOW respectively. These are labeled fph, fpl, fnh and fnl, respectively. For the equality block 516 , the output will be true, i.e., “high,” for the situation where the count value is equal to the value of PE_HIGH of“1.” This will occur when the count value is equal to “1” and will be clocked by an edge 1202 of the high speed clock to provide a true result 1204 represented by a high state. The states for fph, fpl, fnh and fnl are a “0” for a false and a “1” for a true. Similarly, whenever the count value is “2,” fpl will be a true 1206 , indicated as occurring at edge 1208 of the high speed clock. The state of fnh will be a true 1210 at substantially the same time as fpl and fnl being a true 1212 whenever the count value is equal to “3.” This is periodic and, each time the count value is, for example, a “1,” then fph will be true, i.e., corresponding to the output of the equality block 516 .
On the output of the multiplexers 514 and 524 , there are provided a data input to the flip-flops 508 and 510 , respectively. These are referred to as the data states PE_DIV_D for the data on the positive edge and NE_DIV_D for the data to the input of the flip-flop 510 for the negative edge. For the positive edge, the multiplexer 514 first examines the first input to determine if the equality is true. If not, it will go to the next one. For the first count “3” and for the second count “2,” the decision is false and the second input will be evaluated. For the value of “3,” the equality associated with equality of block 518 is false and, therefore, the value will be that of the previous state. However, for a count value of “2,” the multiplexer 514 will select the “0” forced input for input to the input of the flip-flop 508 , such that a “low” will occur at a state 1214 . At the next clock, the counter output is a “1,” which results in the output of the equality block 516 being true and forcing a “1” to the input of flip-flop 508 , at a logic state 1216 . On the next clock cycle, the counter value is a “3,” resulting in the output of equality blocks 516 and 518 being false, such that the previous state is input to the data input flip-flop 508 . This state 1216 is clocked through to the output thereof, represented as a state 1218 . At the clock cycle 1220 , the equality blocks 516 and 518 are false and the output of the flip-flop 508 , being at a high state, will be loaded back into the multiplexer 514 to provide a state 1222 . At the next clock cycle, the counter value is “2” and the equality block 518 will have a true output, forcing a “0” to the input of the flip-flop 508 to provide a state 1224 .
The negative edge operation is also substantially the same. At the clock edge 1208 , the counter is decremented to the value of “2” that will result in the equality block 526 outputting a true determination and this will result in a “1” being forced to the input of the flip-flop 510 , as noted by a state 1228 . When a “1” is provided form the output of the period counter at the next clock cycle at edge 1202 , the output of both equality counters 526 and 528 will be false and the last state, the state 1228 , will be output at a state 1230 . At the next count value of “3” for the clock cycle 1220 , the output of the equality counter 528 is true and that will result in a “0” being forced to the input of the flip-flop 510 at a state 1232 .
The flip-flops 508 and 510 are clocked such that flip-flop 508 is clocked on the positive edge and flip-flop 510 is clocked on the negative edge. Therefore, the state of PE_DIV_D is clocked on the positive edge thereof and the state 1214 will be clocked through on the next rising edge 1202 to change the state to a state 1234 on the output of flip-flop 508 . The state 1228 on NE_DIV_D will be transferred to the output of flip-flop 510 on a negative edge 1236 to be transferred to the state 1228 to the output thereof at a state 1238 . Thereafter, the AND gate 520 will perform the AND function thereof to provide a clock output as set forth in the next diagram, this being a ⅔ clock in accordance with the operation thereof. It can be seen that over three clock periods from a negative edge 1236 to a negative edge 1240 of the master clock, there will be two clock cycles of the output clock. All of the tables and everything are designed to provide such.
Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims. | A fractional divide circuit for generating a periodic fractional clock is disclosed. A base clock is provided for generating a pre-divide clock at a base clock frequency with a period counter provided for counting cycles of the base clock. A select register stores constants that define parameters for a fractional divide ratio, there being at least four. A positive edge flip flop is provided wherein two of the constants are associated therewith. A negative edge flip flop is provided wherein the other of the two constants are associated therewith. A matching device is operable for setting on the positive edge of the base clock the first flip flop when the first of the two associated constants matches the output of the period counter and clearing the first flip flop when the other of the two associated constants matches the output of the period counter, and setting on the negative edge of the base clock the second flip flop when the first of the two associated constants matches the output of the period counter and clearing the second flip flop when the other of the two associated constants matches the output of the period counter. The outputs of the second and first flip flops are ANDed to provide the fractional clock output. | 7 |
BACKGROUND OF THE INVENTION
[0001] In environments that call for an operator to perform various tasks that are located a distance from a control console, it is sometimes challenging to coordinate control intervention with performance of the remote tasks. For example, in a laboratory environment situations often arise where a task demands interaction with a central computer display in conjunction with a set of physical activities that are performed at a distance from the display. Accordingly, an operator may be tasked with attending to a multiple-module in vitro diagnostic instrument system, which places a number of demands on the operator. For example, the operator may obtain a list of reagents from the central display, acquire the reagents from a storage area or refrigerator, pause the in vitro diagnostic instrument at the central display, place the reagents on the module, and return to the central display to acknowledge completion of the operation.
[0002] In such environments as the one described above, the operator is tasked with activities that occur remotely from a central console, while operations for the system are controlled at the central console.
SUMMARY OF THE INVENTION
[0003] The session-state of a local user interface is transferred to a mobile device to permit an operator to execute remote tasks while maintaining interaction with a central controller. The session-state can be transferred between a user interface that is local to a central controller and a mobile computing device using indicia provided by the local user interface or the mobile computing device. The session is identified by the indicia, which is detected by a sensor in the local user interface or the mobile computing device to transfer session-state therebetween. Session-state can be advanced or influenced by input at one platform at a time. Execution of control can continue regardless of the location of session-state interaction. The indicia used to transfer session-state between platforms can be provided in the form of a key or token that includes identifying information for the session.
[0004] The indicia by which the session-state can be transferred can be implemented in accordance with numerous paradigms, including, for example, RFID, a QR code or 2D bar code and scanner or camera, infrared transmissions, near field sensors as well as wired and wireless network connections, to name a few. Standard mobile computing devices may be used as the mobile platform including, for example, smartphones. Upon transfer of the session-state, the platform being relieved of the session-state control can be locked to prevent input/output interaction or control conflicts between the platforms.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] The present disclosure is described in greater detail below, with reference to the accompanying drawings, in which:
[0006] FIG. 1 is a diagram illustrating physical interaction between a control console and a mobile device in accordance with the present disclosure;
[0007] FIG. 2 is a conceptual diagram of interaction between components in accordance with the present disclosure; and
[0008] FIG. 3 is a flowchart illustrating a process for session-state transfer in accordance with the present invention.
DETAILED DESCRIPTION
[0009] The present application claims benefit of provisional application Ser. No. 61/883,359, filed Sep. 27, 2013, the entire disclosure of which is hereby incorporated herein by reference.
[0010] In a computing environment, a software application often proceeds from state to state, as in the case of a state machine, for example, based on detection of various events such as input provided by a user or device, which can be internal or external to the computing environment. State changes are sometimes referred to as transactions, where information is exchanged between two or more components in a computer control system. User initiated state changes can sometimes be implemented through a user interface, such as by a user providing an input to prompt a transaction or state change. The presentation of information in the user interface may sometimes refer to a session. A session is thus sometimes described in terms of an operation instance that involves communication between components, which components may include a user interface operated by a user. A session in a computing environment may be viewed as a control paradigm that involves communication between components. Accordingly, a distinction can be made between a control portion of a session and a communication or interaction portion of a session. For example, some resources in a session can be dedicated to control, while other resources in a session can be dedicated to communication. In accordance with the present disclosure, a communication portion of a session can be redirected or distributed among different devices. Portions of a session can be implemented as a separate process or thread in a computer architecture system to contribute to differentiating portions of a session.
[0011] An application may interact with a user interface with a session model, so that a user at the user interface may participate in a workflow session. The workflow session typically progresses through a number of states in accordance with the application programming, as the user or other devices provide input to the session and receive output or feedback. For example, a user may initiate a workflow session in a distributed computing environment that is constructed with a number of interconnected devices. The workflow session may be initiated at a central console that includes a user interface that permits the user to observe status of the workflow session, and provide input, or otherwise progress the state of the workflow session. One or more of the interconnected devices may also receive commands from and provide feedback to the central console, which may also be used to progress a workflow session state. In such a scenario, the application receives input from and provides output to a number of devices, including the user interface. In accordance with the present disclosure, input to/output from the user interface can be redirected to the mobile device, which can advance the state of the workflow session.
[0012] Referring now to FIG. 1 , a central console 110 is illustrated as interacting with a mobile device 112 . Console 110 represents a user interface with which a user can interact to contribute to controlling a workflow session. Console 110 includes display 102 as an output device that outputs information to a user with respect to a state of the workflow session. The user can provide input from an input device, such as keyboard 104 , which input may be used to control the state of the workflow session implemented with an application running on console 110 . In accordance with the present disclosure, console 110 can provide an output that can be received by mobile device 112 to cause a session-state transfer from console 110 to mobile device 112 . The output provided by console 110 can be implemented according to a number of different forms, including via a wired/wireless network, near-field and RFID communication, infrared communication, a direct wireless or wired connection, by providing a bar code or QR code that can be read by mobile device 112 , and any other type of communication link that can serve to transfer information between console 110 and mobile device 112 .
[0013] Referring now to FIG. 2 , a conceptual relationship 200 of architectural components is illustrated. A system under control 210 interacts with a local controller and control console 212 to provide control and feedback for system 210 . Controller and console 212 represents the application running on console 110 to provide control and receive feedback for system 210 , as well as to operate and interact with a user interface (not shown). Accordingly, local controller and control console 212 may be implemented as console 110 , or as an application running on console 110 . In accordance with the present disclosure, a session-state transfer can be implemented to transfer a session-state to a remote interface 214 . Remote interface 214 can be implemented as mobile device 112 , or as an application running thereon, for example. Upon initiation of a session-state transfer, controller and console 212 provides and remote interface 214 receives information for executing the transfer. According to some embodiments, controller and console 212 , upon transfer of the session-state, prevents further local input from a local control console and accepts input from and provides output to remote interface 214 . In such an instance, local controller and control console 212 may maintain control operations for system 210 in the absence of local input. Accordingly, remote interface 214 can act as a substitute user interface for local controller and control console 212 , and can observe and/or influence the state of the workflow session, such as by advancing the state with user input to remote interface 214 .
[0014] The transfer of session-state to a mobile device, such as mobile device 112 , can be achieved in accordance with an exemplary embodiment by generating or obtaining a session token or a key that describes the state of the workflow session. Such a token can be digital, and can be constructed with information to identify the session, the current state of the session, a computing environment and any other information that can be used to successfully transfer user interface I/O to another device. Such a token can be generated or obtained for each state of the workflow session, so that a token is available for state transfer at an arbitrary point in the workflow session. Alternatively, or in addition, the token can be generated or obtained in response to a prompt to initiate session-state transfer. Security can be established for creation or transfer of the token, such as by requiring a user login to initiate a state-transfer, or by encrypting the token and providing the encryption capability at the target device. The target device can be identified as authorized by console 110 or local controller and control console 212 , so that state-transfer is preauthorized. Moreover, a mobile device, such as mobile device 112 , to which a session-state is transferred can be provided with security to permit initiation of the state-transfer. For example, mobile device 112 can be configured to require a user login to access a transfer facility, or can be provided with specific software that authorizes the session-state transfer.
[0015] The token used for state-transfer can include a session ID that uniquely identifies the workflow session, as well as information related to a particular user's authorization level or preferences. The token may also be constructed to include system parameters, or information that identifies a status of various devices that are connected to a central console, such as console 110 . In general the token includes sufficient information to permit another device to recognize a state of a workflow session, so as to present appropriate output to the device and respond appropriately to input from the device to potentially modify the state of the workflow session. Accordingly, the device to which the token is provided may implement specialized software and/or hardware that recognizes workflow process states, and can identify a current state associated with a received token.
[0016] Various methods and techniques are available for transferring the token from the central console, such as console 110 , to a remote interface, such as mobile device 112 . According to some embodiments, the token is encoded as a one or two dimensional barcode or QR code that can be scanned and interpreted by mobile device 112 , for example. In such embodiments, display 102 is used to display the barcode, and mobile device 112 can capture the barcode via an image capture device such as a camera, which is available with mobile device 112 . The token may also be sent via a network connection including an RFID-type connection, an internet, a Wi-Fi connection, an IR port, a USB port, or any other type of convenient connection that permits transfer of token information from console 110 to mobile device 112 .
[0017] Once the token is transferred to mobile device 112 , for example, software executing on mobile device 112 interprets a state of the workflow session using the information contained in the token. According, mobile device 112 may include software that emulates at least a portion of the user interface associated with console 110 . A user of mobile device 112 can thus observe and influence the state of the workflow session using mobile device 112 , and need not be located directly at console 110 in order to do so.
[0018] Referring now to FIG. 3 , a flowchart 300 illustrates a process in accordance with the present disclosure. The process illustrated in flowchart 300 begins with the initiation of a transfer of the session-state for a workflow session, as illustrated in a block 310 . The initiation of a session-state transfer can be prompted at a local controller, such as console 110 , or can be prompted remotely such as by using mobile device 112 .
[0019] Once the session-state transfer is initiated, a token or session key is generated as illustrated in a block 312 . The session key may also be obtained from a listing of session keys that describe each of the states of the workflow session. For example, a session key can be generated for each state of a workflow session and describe or indicate changes in status for interconnected devices, inputs, outputs, as well as identify the session. Accordingly, multiple session keys may be generated or obtained in accordance with the present disclosure.
[0020] Moreover, multiple sessions may be implemented, controlled and/or transferred in accordance with the present disclosure by generating or obtaining appropriate session keys describing those sessions.
[0021] Once a session key is generated or obtained, it is presented to a communication interface, as shown in a block 314 . The presentation of the session key to a communication interface may be implemented in accordance with any known techniques, including communication with a direct-connect or wireless link, presentation of a bar code, audio code, IR code, or any other type of protocol and/or communication platform that can be used to transfer information. A block 316 illustrates the connection of interfaces between platforms, for example, establishing a connection or transferring information between console 110 and mobile device 112 .
[0022] The transfer of the session key to the new platform is illustrated in a block 318 , where the receiving platform, which can be mobile device 112 , obtains the session key that identifies the session-state of the workflow session.
[0023] Upon transfer of the session key, the central console may disable the user interface from receiving input, to avoid ambiguous or conflicting input commands, as illustrated in a block 320 . Disabling input from the user interface can be implemented by blocking inputs from an input device, or reading and discarding the inputs. For example, in a Windows environment, an input handler can be configured to read inputs from a keyboard or mouse as is normally done, and then avoid transfer of the input to the workflow session application, so that input to the central console appears to be disabled.
[0024] The session key obtained by the receiving platform is interpreted to identify the session and the state of the session to permit implementation of an interactive user interface at the new platform. Inputs and outputs at the new platform affecting the state of the workflow session may then be used to interact with the workflow session, as illustrated in a block 322 . The interaction with the workflow session from the new platform may be implemented by providing a workflow session emulator on the new platform that uses the session key to establish a current state of the workflow session for the user interface on the new platform. In such an instance, input and output may be provided to and derived from a controller of the system directly, effectively bypassing the user interface of the central console. Alternatively, or in addition, the new platform can provide user input to a workflow session instead of the central console, and receive outputs from the workflow session instead of the central console. According to this alternative, the new platform need not implement a workflow session emulator, and can be provided instead with a less complex user interface emulator. These alternatives can permit multiple workflow sessions to operate in parallel, or as a single entity that provides user interface interaction with different devices, depending on the location of the current user interface. For example, the current interface may be identified as mobile device 112 , or as console 110 , or both. In some embodiments, some workflow sessions can be directed to have console 110 serve as the user interface, while some workflow sessions can be directed to have mobile device 112 serve as the user interface. Accordingly, multiple workflow sessions can be operating simultaneously, and controlled or observed at either console 110 or mobile device 112 . In any case, obtaining a session key at a given user interface platform permits that platform to assert control over the user interface for a given workflow session, and cause some or all other platforms to be excluded from user interface interaction. The enablement of a user interface at a new platform with a current session-state is illustrated in a block 324 of flowchart 300 .
[0025] Although the present disclosure describes a target device as generally being a computing device, the disclosed systems and methods can be generally implemented with target devices, systems or methods that may not always be thought of in terms of computing devices. Examples of such targets that may employ the presently disclosed systems and/or methods include televisions, mobile phones, automotive vehicles, medical instrumentation, as well as typical targets for software updates such as database applications or embedded systems. In general, the disclosed systems or methods may be applied with any type of processing system that executes software.
[0026] The operations herein described are purely exemplary and imply no particular order. Further, the operations can be used in any sequence when appropriate and can be partially used. With the above embodiments in mind, it should be understood that the disclosed systems, devices, methods and/or uses can employ various computer-implemented operations involving data transferred or stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical, magnetic, or optical signals capable of being stored, transferred, combined, compared, and otherwise manipulated.
[0027] Any of the operations described herein that form part of the present disclosure are useful machine operations. The present disclosure also relates to a device or an apparatus for performing these operations. The apparatus can be specially constructed for the required purpose, or the apparatus can be a general-purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general-purpose machines employing one or more processors coupled to one or more computer readable medium, described below, can be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations.
[0028] The disclosed system and method can also be embodied as computer readable code on a computer readable medium. The computer readable medium is any data storage device that can store data, which can thereafter be read by a computer system. Examples of the computer readable medium include hard drives, read-only memory, random-access memory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network-coupled computer system so that the computer readable code is stored and executed in a distributed fashion.
[0029] The foregoing description has been directed to particular embodiments of the present disclosure. It will be apparent; however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. The procedures, processes and/or modules described herein may be implemented in hardware, software, embodied as a computer-readable medium having program instructions, firmware, or a combination thereof. For example, the functions described herein may be performed by a processor executing program instructions out of a memory or other storage device. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the present disclosure. | The session-state of a local user interface is transferred to a mobile device to permit an operator to execute remote tasks while maintaining interaction with a central controller. The session-state can be transferred between a user interface that is local to a central controller and a mobile computing device using indicia provided by the local user interface or the mobile computing device. The session is identified by the indicia, which is detected by a sensor in the local user interface or the mobile computing device to transfer session-state therebetween. Session-state can be advanced or influenced by, input at one platform at a time. Execution of control can continue regardless of the location of session-state interaction. The indicia used to transfer session-state between platforms can be provided in the form of a key or token that includes identifying information for the session. | 7 |
RELATED APPLICATIONS
This application is a continuation in part of Ser. No. 986,934 filed Dec. 08, 1992.
FIELD OF INVENTION
This invention relates to a simple manual appliance for dispensing and applying masking to a surface generally in preparation for painting. The term "masking" as used herein refers to a band of masking paper or the like of indefinite length with an overlapping band of masking tape applied along the length of the paper.
BACKGROUND OF INVENTION
Appliances for dispensing masking are disclosed in the following prior art:
______________________________________U.S. Pat. No. 3,787,271 WahlquistU.S. Pat. No. 3,950,214 Pool et alU.S. Pat. No. 4,096,021 Pool et al______________________________________
Each of the disclosed appliances include a frame, and mounted therefrom a paper roll holder, a tape roll hold and a handle, and optionally a masking guide locating forwardly of the paper roll holder. The disclosed appliances are all handed, which is to say that they are devoid of symmetry. The effect of this is that for certain applications, for example where the masking is to be applied along an inside vertical corner of a room, if the applicator is suited for applying the masking to the corner in a downward movement, it will be unsuited for applying the masking to the corner in an upward movement.
The masking will be generally withdrawn from the appliance in a plane defined by a masking support bar, which is disposed forwardly of the paper roll, over which bar the masking passes as it is dispensed from the appliance. Where the handle of the appliance is significantly offset from this plane a torque is developed as the masking is dispensed, which leads to operator fatigue.
The prior art appliances are suited for construction from metal, with relatively long paper roll holders and masking guides cantilevered outwardly from the frame. Such appliances are relatively heavy and are not readily adapted for molding in thermo plastic materials.
The prior an appliances tend to be relatively bulky whereby they are not entirely suited for use in confined spaces.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a manual appliance for forming and dispensing masking that may be non-handed.
It is another object of this invention to provide a manual appliance for forming and dispensing masking that is suited for manufacture from plastic materials.
It is still another object of this invention to provide a manual appliance for forming and dispensing masking that is relatively compact and lightweight.
It is yet another object of this invention to provide a manual appliance for forming and dispensing masking that reduces operator fatigue.
In accordance with the broad aspects of the invention, a manual appliance for forming and dispensing masking from masking paper and masking tape separately stored on rolls comprises a frame which is defined by a rear wall, a front wall and a pair of side walls connecting the rear wall and from wall in a generally rectangular arrangement. A masking paper roll holder having an axis therealong extends within the frame between the two side walls, parallel to the front wall. The front wall serves as a guide for the masking being dispensed from the appliance, and has masking severing means associated therewith, suitably in the form of a stationary serrated cutting edge. A handle including a handle portion having an axis therealong is associated with the rear wall, and may suitably comprise a minor portion of the rear wall which is rearwardly offset from the major portion thereof. A masking tape roll holder is normally supported from the frame rearwardly of the rear wall. The front wall, the axis of the masking paper roll holder and the axis of the handle are all contained in a thick plane, and for most purposes, at least insofar as a user of the appliance is concerned, the front wall, the handle and the paper roll holder will appear to have a common plane of symmetry contained within the thick plane. This apparent symmetry permits the use of the appliance in both a left handed and a right handed manner. Additionally, in such appliance the masking will normally be withdrawn therefrom in a plane within the thick plane or close thereto. Accordingly, the disposition of the handle within this plane reduces operator fatigue resulting from torque forces generated at the handle.
The axis handle of the appliance preferably extends parallel to the axis of the paper roll holder, and the handle suitably forms an integral part of the rear wall, and the frame including the handle and a support bracket forming a part of the masking tape roll holder may be unitarily formed as a plastic molding. This substantially reduces the weight of the appliance without detrimental effect on the rigidity, further contributing to a reduction in operator fatigue while permitting the accurate positioning of masking dispensed from the appliance.
In accordance with one embodiment, the front wall, i.e. the masking guide, is provided with a slot therealong disposed in the plane containing the axis of the handle and paper roll holder extending continuously to adjacent each side wall, through which the masking is dispensed, and has tooth like serrations on opposed sides of the slot to form the masking severing means.
These foregoing objects and aspects of the invention, together with other objects, aspects and advantages thereof will be more apparent from the following description of a preferred embodiment thereof, taken in conjunction with the following drawings.
IN THE DRAWINGS
FIG. 1--shows in perspective, exploded view the appliance of the invention, together with a roll of masking tape and masking paper; broken away to reveal detail;
FIG. 2--shows the appliance of FIG. 1, assembled and in use, in perspective view, rotated through 180° out of the plane of paper in relation to FIG. 1;
FIG. 3--is a view on line 3--3 of FIG. 1;
FIG. 4--shows in perspective exploded view a modified version of the frame portion of the appliance; and
FIG. 5--is a view on line 5--5 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings in detail, a masking forming and dispensing appliance in accordance with the invention is identified therein generally by the numeral 10. Appliance 10 comprises a generally rectangular frame 12 including four wail portions, namely a first side wall 14, second side wall 16, a rear wall 18 and front wall 20.
Each of walls 14, 16, 18, 20 has a generally similar height whereby frame 12 may be considered to reside in a thick plane. Walls 18 and 20 along the length thereof are considered to define the axial direction of frame 12. A paper roll holder 24 extends between side walls 14, 16 and is releasably supported thereby, for which purpose side wall 16 is provided with a central circular opening 26 therethrough, through which paper roll holder 24 will pass snugly, and side wall 14 is provided with a rectangular opening 28 therethrough concentred with opening 26. Opening 28 is surrounded on the inner side of wall 14 by an inwardly projecting boss 30, and on the outer side of wall 14 by a recess 32. Holder 24 is provided at one axial end thereof with a pair of legs having hooked ends 34 which snap fit through opening 28 without projecting outwardly of recess 32, to releasably retain holder 24 in a non-rotatable relationship in frame 12. Holder 24 has a cruciform cross section; first and second pairs of diametrically opposed stop shoulders 36,38 are axially spaced apart on holder 24, shoulders 38 being rotated through 90° in relation to shoulders 36. A stop collar 40 having an opening 42 therethrough restricted by a pair of diametrically opposed triangular tabs 44 is slidable along holder 24 until tabs 44 abuts stop shoulders 36, or if rotated through 90°, stop shoulders 38.
With stop collar 40 positioned on holder 24 in abutment with stop shoulders 36, and holder 24 secured to frame 12, the distance between boss 30 and stop collar 40 will be equal to the standard width of a roll R of masking paper; when stop collar 40 is adjusted to be in abutment with stop shoulders 38, the distance will be equal to a different standard width roll, and with the stop collar removed, the distance between boss 30 and side wall 16 will be equal to that of still another standard width roll.
Front wall 20 has a slot 46 therethrough at mid height extending continuously to adjacent each side wall 14,16, a plane containing slot 46 bisecting frame 12 and containing the geometric axis of holder 24.
Slot 46 serves to divide wall 20 into two opposed jaws 48 one of which is more forwardly disposed than the other. The forward face of each of jaws 48 is forwardly inclined towards slot 46, and is provided with tooth like serrations 50 therealong.
Appliance 10 further includes a handle 54 and handle arms 56 which connect to rear wall 18 on opposed sides of a lacuna 52 formed in the rear wall adjacent side wall 14. One of the handle arms 56 extends rearwardly of handle 54 in a portion 56a, to which extension a tape roll holder 58 is rotationally connected by a pivot 60. The plane containing slot 46 also contain the geometric axis of handle 54.
Considering now the operation of appliance 10, and with specific reference to FIG. 1 wherein tape roll holder 58 locates at the left hand side of the appliance, as viewed from a forward direction, paper roll R is engaged on paper roll holder 24 as the latter is urged through opening 26 towards the left hand side of frame 12, with stop collar 40 suitably located on holder 24 as earlier described, or omitted therefrom as the case may be, according to the width of paper roll R, so that when holder 24 is snapped into position roll R will be free to rotate on the holder, but will be retained in a fixed axial position. The leading edge L of masking paper from roll R is threaded manually through slot 46 in a manner to exit forwardly therefrom, the forward offset of one of jaws 48 from the other facilitating the threading. The threading is further facilitated by rounding jaws 48 at 62 at the rearward entrance to slot 46. A roll of masking tape T is engaged on tape roll holder 58, it being noted that the masking tape T and paper roll R are both positioned in a manner to unwind in the same rotational sense from the top of the respective rolls. The axial offset of arm 56 earlier spoken of will be such that masking tape from roll T overlaps the left hand margin of the masking paper from roll R, as will be appreciated best from FIG. 2, to form a composite masking M for application to a surface. When a sufficient length of masking M has been dispensed, it may be severed by either of jaws 48 by a upward or downward movement of jaws 48, as is convenient. During the severing operation and at other times it is often desirable to prevent masking paper roll R from turning, or to provide a frictional resistance to turning, and handles 54 is disposed on frame 12 whereby when the handle is grasped by the hand H of a user during normal operation, as seen in FIG. 2, one or more fingers of that hand may extend to about the geometric axis of roll R whereby a suitable braking resistance may be provided by the fingers.
The appliance 10 having the orientation shown in FIG. 1 will be best suited for applying meshing M in a downward direction in a corner at to the right of a user, and is considered to be set up for right handed operation. By contrast, the appliance as seen in FIG. 2 is set up for left handed operation in which meshing may be applied in a downward direction to a corner on the left hand side of the operator. For most intents and purposes, appliance 10 when set up for right handed operation will appear to a user to be the mirror image of the appliance when set up for left handed operation.
With reference to FIGS. 4 and 5, which illustrate certain modifications to the frame portion of the appliance 10 of FIGS. 1 to 3, similar parts are identified where necessary by similar numerals to those earlier employed, augmented by 100. Thus frame 112 comprises a rear wall 118, to which is secured a spring finger 119 that will exert a frictional force on a masking paper roll R. An adjustment screw 121 permits the spring finger 119 to be moved in a manner to adjust the spring finger for right and left handed use of the appliance. In this embodiment, arm extension 156a is somewhat enlarged and two openings 159 are provided through either of which openings a pivot pin 160 may be inserted to retain tape roll holder 158 in either of two positions on frame 112. It will be appreciated that should it be desired, more openings 159 could be provided in arm extension 156a to provide more positions for securing tape roll holder 158.
The front wall 120 of frame 112 is reduced in height adjacent the forward end thereof, and is provided with a cutting edge 150 therealong which is suitably in the form of a metal insert. Since frame 112 is symmetric about a plane containing cutting edge 150, the masking will be dispensed beneath front wall 120 in an identical manner irrespectively of whether frame 112 is oriented as illustrated or flipped over side for side for left handed operation.
It will be apparent that many changes may be made to the illustrative embodiment while falling within the scope of the invention, and it is intended that all such changes be covered by the claims appended hereto. | An appliance for forming and dispensing masking from a roll of masking paper and a roll of masking tape is suitably formed as a lightweight plastic molding having a compact profile. The appliance is generally symmetrical about a front to back plane whereby it is non-handed, so permitting the appliance to be oriented at all times in a preferred manner when the masking is applied to a surface. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 12/009,492 filed Jan. 18, 2008, which claims the priority of U.S. Provisional Application No. 60/885,888 filed Jan. 20, 2007, the entire contents of which are incorporated herein.
BACKGROUND
Absorption spectroscopy uses the range of electromagnetic spectra in which a substance absorbs. In absorption spectroscopy light of a particular wavelength is passed through the sample. After calibration, the amount of absorption can be related to the sample concentration through the Beer-Lambert law. Examples of absorption spectroscopy include, for example, ultraviolet/visible (UV/VIS) absorption spectroscopy (most often performed on liquid samples to detect molecular content) and infrared (IR) spectroscopy (most often performed on liquid, semi-liquid (paste or grease), dried, or solid samples to determine molecular information, including structural information).
Spectroscopic analysis typically uses a spectrometer. The spectrometer typically includes a radiation source such as a deuterium, tungsten or xenon lamp capable of emitting radiation over a very broad range of wavelengths. The light is coupled into a sample held in a sample cell. The spectrometer filters the light emitted by the lamp, before or after coupling with the sample, by use of monochromators, filters, gratings, etc. A detector, for example, a photodiode, photomultiplier, photodiode array, or CCD array, quantifies the amount of light passed through (absorption) or emitted by (fluorescence) the sample to provide a detectable signal. While this equipment provides analysis flexibility, it also requires complicated and expensive light sources, gratings, monochromators and other components to take advantage of this flexibility.
Some experiments and tests do not need a spectrometer with full wavelength coverage, but may be performed using light in a single wavelength or only a few wavelengths. For example, applications in the oceanographic field include nutrient analysis, e.g. nitrite/nitrate requiring light at only 540 nm, phosphate requiring light at only 880 nm or 710 nm and iron requiring light at only 562 nm when using colorimetric techniques. Further, applications in biochemistry include protein detection, which could either be performed directly in the UV at 280 nm, or via colorimetric techniques, such as the modified Lowry Protein Assay, with detection at 650 nm (normalized at 405 nm) or the Bradford Assay, where the bound protein-dye complex is measured at 595 nm and can be normalized in the 700 to 750 nm region. Most of these analyses can be performed using single wavelength detection. Their accuracy could be improved by using a second wavelength for baseline offset and a third and/or fourth wavelength for simple absorbance shape detection to eliminate or indicate other colorimetric substances in the sample solution and correct for them. However, in some applications these improvements are not needed.
LEDs have long been used as quasi-monochromatic light sources. They are readily available for nearly all parts of visible light spectra. Recently UV LEDs with emission wavelength as low as 250 nm have become commercially available. Belz, M., Photonics West 2007. Many application specific LED-based detection systems have been developed and patented. Recently, an optical arrangement for assay strips was designed and disclosed in U.S. Pat. No. 7,315,378. It purportedly allowed the reliable reading of optical test strips and was based on several LEDs and photodetectors. These detection systems usually rely on single wavelength detection and may use a second photodiode to correct for the inherent drift behavior of the LED. A filterless chromatically variable light source, wherein light is coupled via optical fibers from several LEDs into a single optical fiber is disclosed in U.S. Pat. No. 5,636,303. The disclosed light source allowed individual control of the intensity of each LED to generate either light of a particular wavelength or a white light spectrum.
SUMMARY OF THE DISCLOSURE
A self-referencing LED based detection system with multiple wavelengths (LEDs) is employed for spectroscopy applications. The system may be exemplified by a flow injection based absorbance detection system, but is not limited to this application and may be used for small sample volume discrete measurements, as well as for fluorescence applications. Although LEDs have the tendency to drift in light output power as a function a temperature caused by self-heating, stable output powers can be achieved by driving them in constant current mode and measuring their output with a reference detector. Detection at multiple wavelengths is realized by using several LEDs which emit at different wavelengths, coupling each of them into an optical fiber and coupling these fibers into a single fiber of large diameter for mixing their emission spectra and providing a stable consistent light output at the end of the large mixing fiber. Light is coupled to a reference photodiode and to the fiber optic output at the end of the fiber.
A sample cell is connected to the detection system via the fiber optic output and the sample photodiode input. LEDs are switched on and off sequentially. Light output is measured simultaneously by the reference photodiode and the sample photodiode. Thus, dark, reference and sample intensity are detected simultaneously and any LED drift or stray light can be corrected for automatically, ensuring precise measurements and long-term drift stability. To reduce the spectral bandwidth of the LEDs, interference filters are either placed between the LED and the coupling fiber or are coated directly on the LED coupling fiber to optimize light throughput.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an annotated block diagram of an LED detection instrument and associated sample cells;
FIG. 2 is an annotated block diagram of a UV LED detection system with a reference channel for biochemistry applications;
FIG. 3 is an annotated block diagram of multi-channel VIS LED detection system with a reference channel for oceanographic and process control applications;
FIG. 4 is an annotated block diagram of a single channel setup of a flow injection system;
FIG. 5 is a graph of a normalized absorbance for DNA and Protein (BSA);
FIG. 6 is a graph of a normalized intensity distribution of UV LEDs with a center wavelength of 260 nm and 280 nm, with and without a 10 nm interference filter;
FIG. 7 is a graph of a simulated decrease of absorbance for DNA at 260 nm and BSA at 280 nm wavelength as a function of increasing the spectral bandwidth (FWHM) of a detection system; and
FIG. 8 is a graph of absorbance of BSA at 280 nm versus concentration measured with a TIDAS II™ spectrophotometer and an LED detection system with and without a 10 nm bandpass filter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An LED based spectrophotometric detection system performs absorbance or fluorescence spectroscopy and may take several forms as described below. One LED provides light at one wavelength or by manually or automatically sequentially switching LEDs of different colors (wavelengths) tailored for specific applications. In advantageous variations the detection system may use a standard interface such that different LED emission modules, each with LEDs selected for a specific wavelength, can be attached. Advantageously, the LED or LED modules selected will each provide light in a narrow wavelength range falling within the UV, VIS, NIR and IR region of the light spectrum. Such LEDs or LED emission modules are supplied with power to emit light. The emitted light is coupled into a sample held in a fiber optic sample cell, such as a flow cell, long path cell, dipping probe, external curette holder or a reflection probe. In one embodiment the sample is contained in a liquid wavelength capillary cell (LWCC) marketed by World Precision Instruments, Inc. Other compatible commercial sample cells are fiber optic curette holders, DipTip™ fiber optic probes and SpectroPipetter™ probes marketed by World Precision Instruments, Inc.
A detector measures light passed through (absorption) or emitted by (fluorescence) the sample to provide an indication of the presence and/or amount of the sample present. An LED based detection system used to measure fluorescence signals would have much higher sensitivity than standard fiber optic based spectrometers. A commercially available low noise photodiode is used to detect LED emissions.
With reference to FIG. 1 a colorimetric detection instrument designated generally by the numeral 10 is illustrated as it interfaces with four sample cells 12 , 14 , 16 and 18 containing samples 51 , 52 , 53 and 54 respectively. Advantageously, the instrument 10 provided by the system functions like a dual beam spectrometer for specific wavelength applications. In this embodiment, as described below the instrument 10 is self correcting for LED intensity drift by use of a reference channel, self correcting for ambient light by measurement of dark current after each pulsed sample or reference measurement and has the capability to work with a phase locked loop to reject AC type stray light influencing the light measurement.
With additional reference to FIGS. 2 and 3 , embodiments of additional LED detection systems 100 and 200 adapted for specific applications are schematically illustrated. Block functions, inputs and outputs for the various embodiments are discussed with reference to FIG. 1 . The instrument has a mechanical interface that will accept two or more LEDs or LED modules of different wavelengths which are selected for a specific analysis to be undertaken. A microcontroller 20 provides control and interface signals to the system components. The microcontroller 20 provides timing and on/off control for the LED drivers 30 .
A detector, for example a photodiode, is used to detect light passed through, or emitted by, the samples and, advantageously, from the reference. The detector current is converted to voltage. This analog voltage may then advantageously be converted into a digital signal by ND 32 that will be sent to the microcontroller 20 . Reference and post experiment scaled and converted data may be provided as inputs from the A/D converter 32 . The post experiment data will be sent as an output to the digital to analog converter (DAC) 34 to provide analog values. The instrument has a mechanical interface that will accept two or more LEDs or LED modules of different wavelengths which are selected for a specific analysis to be undertaken.
Detection instrument 10 functions as a self-referencing optical detection system. Light Emitting Diodes (LEDS) 51 - 57 are used as quasi-monochromatic light sources. They are sequentially switched on and off to generate a train of light intensities at different wavelengths. Up to 7 LEDS are possible in this arrangement. In this arrangement, light of the different LEDs is coupled via a optical fiber of e.g. 750 m core diameter into a 3000 m “fiber combiner” 60 . The fiber combiner 60 , uniformly combines and mixes the light. Light is coupled out of the combiner into five separate output fibers 61 - 65 . One fiber 61 is directly connected into a reference photodiode 40 . The purpose of the reference diode 40 is to quantify the LED light output and use it to compensate for light power drift of the LED during the measurement cycle.
A 16 bit digital to analog converter (DAC) 36 is used to control the output of each individual LED 51 - 57 , matching it to the samples S 1 , S 2 , S 3 , S 4 , used. Four optical fibers 61 - 64 are used to provide light to four independent external sample cells 12 , 14 , 16 , 18 (Sample 1 , 2 , 3 & 4 ). Light is coupled into and out of the sample cells via optical fibers. Four separate photodiodes 41 - 44 are used to measure the corresponding light levels exiting the sample cells. A 24 bit A/D converter 32 is used to convert the analog signals from the photodiodes 40 - 44 into the digital domain.
The microcontroller 20 is used to control all aspects of the measurement cycle. The 8 channel DAC 36 controlling the LED power allows the instrument to optimize light throughput in the sample cells, tailoring the light output of the sample cells to the analog photodiode input of the instrument. A simple keyboard 22 allows for setting the parameters of a measurement cycle. Parameters and measurement results are displayed on the LCD display 24 . The measurement result is scaled to the DAC-Analog Output 34 and is further available in digital format via the USB interface 26 . Eight digital inputs and eight outputs 28 are available to receive trigger inputs and run experimental setups, such as, for example, pump 72 and valve 74 illustrated in FIG. 4 .
Methods can be programmed to automate experimental procedures, such as e.g. fluid injection based nitrite/nitrate or phosphate analysis. Further, a software package can communicate via the USB interface 26 with the detection instrument to change parameters and receive and store experimental data. In a single measurement cycle, dark readings, sample readings and reference readings are collected. One advantage of the system is that due to its monochromatic light excitation principle, stray light effects are far smaller than in traditional spectrometer systems. Thus, the upper limit of the dynamic range of the detection system is increased from the traditional 2 AU to 3-4 AU. A second advantage of the system is that due to the constant tracking of the reference signal, signal drift is virtually non-existent. Absorbance drifts smaller than 0.5 mAU over a period of several days have been obtained. Thirdly, due to the constant detection of the dark output, stray light induced offsets from external light collection are automatically corrected for. Fourthly, synchronous detection of sample and reference signals is possible.
The following examples are included for purposes of illustration so that the disclosure may be more readily understood and are in no way intended to limit the scope of the disclosure unless otherwise specifically indicated.
DNA and RNA Detection Example
With reference to FIG. 2 , LED detection system 100 which shows how detection instrument 10 may be configured for DNA and RNA detection, employs three UV LEDs (260, 280, 380 nm) designated 50 A, 50 B and 50 C. Fiber optic coupling connects the LEDs to the reference photodiode 40 and the sample photodiode 41 via a sample cell 12 . LEDs 50 A, 50 B, 50 C were driven in current mode with 10 to 20 mA. A fiber optic bundle 80 with three input (one per LED) and two outputs for the reference and the sample channel was prepared from solarization resistant fused silica fibers. A fiber optic cuvette holder and standard 10 mm quartz cuvettes were used for sample analysis.
Traditional LEDs have a spectral bandwidth in the area of 7-30 nm with a trailing edge towards the longer wavelength. A typical biochemistry example is the detection of DNA and BSA concentrations at 260 nm and 280 nm, respectively. Pure DNA exhibits an absorbance of 1.0 AU at 260 nm for a 50 μg/mL concentration, whereby a BSA standard solution of 2.0 mg/mL has an absorbance of 1.33 AU at 280 nm. Further, the purity of DNA can be determined calculating the absorbance ratio at 260 nm and 280 nm, which should be 1.8 or above. However, to perform the measurements correctly, the spectral instrument bandwidth has to be accounted for. The spectral measured bandwidth full bandwidth half maximum (FWHM), of the clearly defined DNA and BSA absorbance peak is approximately 43 nm and 31 nm, respectively. Traditionally, measurements are performed with detector systems having a spectral bandwidth (FWHM) of 1/10 th of the sample absorbance peak. This would result in an instrument bandwidth requirement of 4.3 nm and 3.1 nm for BSA and DNA. Nevertheless, in recent years, spectrophotometers with bandwidth of 5 nm and above have been used routinely in life science research for quantification and purity determination of DNA. In a first approximation, the spectral bandwidth of DNA and BSA can be estimated to 43 nm and 31 nm, respectively. The peaks are spaced 20 nm apart, but overlap significantly. DNA purity can be assessed by calculating the absorbance ratio at 260 nm and 280 nm. Pure DNA, as used in this example exhibits an absorbance ratio A260/A280>1.8
Following the Beer-Lambert-Bouguer law, the spectral absorbance, ABS Sample-Spec (λ), through a sample, is as follows:
ABS
Sample
-
Spec
(
λ
)
=
I
Re
f
(
λ
)
I
Sam
(
λ
)
=
ɛ
(
λ
)
lc
.
(
1
)
It is proportional to the sample concentration, c, the path length, l, and its material specific extinction coefficient, ε(λ), where I Ref (λ) is the incident or reference intensity, I Sam (λ) is the transmitted or sample intensity and λ is the wavelength of light. The spectral (reference) intensity distribution of a LED, I REF-LED (λ), can be approximated by a Gaussian intensity distribution as follows:
I
Re
f
-
LED
(
λ
)
=
I
0
10
l
n
(
2
)
(
λ
-
λ
c
)
2
(
FWHM
2
)
2
.
(
2
)
where I 0 is the peak intensity, λ c is the center wavelength of the LED or filter, if used, and FWHM represents the spectral bandwidth measured as Full Width Half Maximum. Thus, the LED light intensity distribution transmitted through the sample, I Sam-LED(λ) may be written as:
I Sam-LED (λ)= I Ref-LED (λ)10 −ABS Sample-Spec (λ) (3)
However, in the optical setup used, light intensity is detected by a photodiode; in this case, the total absorbance of the sample, ABS Sample-LED , measured with the LED detection scheme can be estimated to be:
ABS
Sample
-
LED
=
log
∫
λ
1
λ
2
I
Re
f
-
LED
(
λ
)
I
Sam
-
LED
(
λ
)
ⅆ
λ
(
4
)
where λ 1 and λ 2 are the lower and the upper limit, defined by a reduction of spectral intensity to less than 5% related to the maximum 100% at center peak wavelength.
The effect of increasing the spectral bandwidth, measured as FWHM, of the detection system on the absorbance signal, when measuring DNA and 260 nm and BSA at 280 nm was simulated using equations 1-4 and the results from FIG. 6 . In particular, LED intensity distributions with FWHM values ranging from 3 nm to 20 nm were generated and ABS Sample-LED calculated. The decrease of absorbance when measuring DNA at 260 nm wavelength as a function of LED FWHM was found to be less significant than the decrease of BSA absorbance at 280 nm. Allowing for a 5% decrease in absorbance, the FWHM of the detection system could be increased from 2.5 nm (spectral bandwidth of the spectrophotometer) to 9 nm and 13 nm for BSA at 280 nm and DNA at 260 nm, respectively.
Relative spectral intensity distributions of UV LEDs with a center wavelength at 260 nm and 280 nm as a function of wavelength were measured with a spectrophotometer. The resolution of the spectrometer was confirmed to be 2.5 nm using a mercury spectral calibration lamp at 253.7 nm wavelength. Further, center-wavelength matched interference filter with a resolution of 10 nm were placed between UV-LED and the fiber coupling block to restrict their spectral output ( FIG. 6 ). The center wavelengths of the 260 nm and 280 nm LED were found to be 262 and 281 nm, respectively. FWHM of both LEDs was 13 nm and 10 nm, respectively. Although the FWHM of both LEDs may be adequate, light intensity above 10% can be seen from 262 nm to 278 nm for the 260 nm LED and 281 nm to 293 nm for the 280 nm LED. As light at these wavelengths may interfere with the sample measurement, interference filters were employed. Compared to the raw intensity distribution of the LEDs, the FWHM of the 260 nm/filter combination was reduced to 8 nm and the 280 nm/filter combination to 7 nm wavelength. More importantly, the intensity distributions became symmetric to the center wavelength and the overlapping light levels in the 265 nm to 275 nm region were significantly reduced. These separate optical components can be replaced by coating the front end 82 , 84 , 86 of the coupling fiber with an interference filter of appropriate wavelength.
BSA concentrations in the region of 0.1 mg/L to 8 mg/L were prepared by gravimetric dilution in ultrapure water. Absorbance was measured at 280 nm with a spectrophotometer and the LED detection system 100 ( FIG. 8 ). For comparison, absorbance was measured with and without the interference filter. The TIDAS II™ spectrophotometer marketed by World Precision Instruments, Inc. exhibits a typical concentration to absorbance calibration. A linear behavior is found between 0 and 2.3 AU; then, the stray light of the detector limits the detection range. The LED detection system 100 without the 280 nm interference filter shows strongly non linear behavior between concentration and absorbance. This can be explained by the fact, that the 280 nm LED emits light up to 310 nm wavelength, where there is only minor absorbance of BSA ( FIG. 5 ). This effect is responsible for the increasing non-linearity of the calibration curve, as the portion of light in this region stays constant and reduces the total absorbance signal observed by the sample photodiode 41 ( FIG. 8 ). However, after the 280 nm bandpass filter is implemented, spectral bandwidth of the 280 nm LED is greatly reduced to 7 nm FWHM ( FIG. 8 ).
With the filter installed, the concentration to absorbance calibration improves significantly. Up to 3.0 AU can be measured with this setup resulting into a R 2 of 0.9991 in this range. The spectrophotometer used for comparison only allows for an upper detection limit of 2.3 AU due to stray light effects within its polychromator. The greater dynamic range of the LED detection system can be explained by the monochromatic nature of the detection system. Only light at the wavelength of interest is generated with the LED detection system and used for the measurement.
The LED detection system 200 which employs seven LEDs 51 - 57 is adapted for use in oceanographic and process applications. The selected wavelengths are indicated. Band pass or short pass filters 91 - 97 reduce the spectral bandwidths of the emitted radiation. | A light emitting diode (LED) based detection system is employed for spectroscopy based applications. LEDs are used as monochromatic light sources for applications at specific and pre-defined wavelengths. Spectrographic information is generated using LEDs of different wavelengths ranging from 260 nm to 1400 nm. Multiple wavelength information is generated by coupling light from each LED into an intensity and mode mixing fiber bundle. A dual beam approach of using a reference and a sample photodiode ensures automatic drift correction. Interference filters at the LED input fiber reduce the spectral bandwidth of the monochromatic light emission to a useful 10 nm bandwidth by cutting off the LEDs trailing emission distribution allowing for absorbance measurements similar to typical spectrometers. | 2 |
FIELD OF THE INVENTION
The present invention relates to an apparatus for the analysis of a groundwater sample. More particularly, the present apparatus relates to a flow through cell for continuously analyzing the groundwater such that the user is provided with the opportunity of purging a minimum amount of water before a groundwater sample is accepted for analysis.
BACKGROUND OF THE INVENTION
Recent increases in public concern for the environment have resulted in various government imposed environmental regulations. Among such regulations are requirements relating to the monitoring of groundwater quality. In response to these requirements, water quality analytic capabilities have been improved and water sampling equipment has been developed. Much has not been effective, however, in obtaining consistent, non-contaminated water samples that are accurately representative of the water system from which the sample is taken.
Groundwater quality is monitored by drilling one or more groundwater monitoring wells in the area where it is necessary to periodically observe the quality of the groundwater. Preferably, a dedicated fluid sampling apparatus is positioned in each of the monitoring wells for obtaining an acceptable sample of the groundwater. A fluid sampling apparatus for use in conjunction with the present invention is disclosed in U.S. Pat. No. 4,489,779 issued Dec. 25, 1984 to Dickenson et al. and U.S. Pat. No. 4,585,060 issued Apr. 29, 1986 to Bernardin et al., the disclosures of which are hereby incorporated by reference.
Prior to obtaining an acceptable water sample from the monitoring well, the monitoring well must be purged approximately three to five times before a representative sample of the groundwater is available. In order to insure that a representative sample of the groundwater is available prior to accepting the sample, prior art sampling equipment operate in one of two ways. First, the equipment will simply purge the well an excessive number of times to insure a representative sample is available. This method proves to be unacceptable due to the excessive amount of water being purged, the excessive length of time involved in purging the well and the fact that it is never actually known if your sample is representative because it is assumed to be representative due to the excessive amount of purging.
The second method available to the prior art sampling equipment is to periodically test a sample until two or three samples have similar readings or until the readings have stabilized. While this method insure that a representative groundwater sample will be accepted, the process proves to be both time consuming and cumbersome.
Accordingly, what is needed is an apparatus which continuously monitors specified parameters of the groundwater as it is being pumped from the monitoring well. By continuously monitoring specified parameters of the groundwater being pumped, it is possible to obtain a representative sample in the shortest amount of time and with the minimum amount of groundwater having to be purged from the well. A groundwater sample is accepted once the specified parameters have stabilized.
SUMMARY OF THE INVENTION
The present invention discloses a flow-through cell which is equipped with at least one monitoring probe having at least one sensor. A portion or all of the groundwater is continuously diverted through the flow-through cell where specified parameters are continuously evaluated. Once these specified parameters are stabilized, a representative groundwater sample can be taken for further analysis.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features and objectives of this invention and the manner of attaining them will become more apparent and the invention will be better understood by reference to the following description of the invention taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a partially exploded, longitudinal sectional view of a fluid sampling system which uses the flow-through cell with diverter circuit of the present invention.
FIG. 2 is a side view of the diverter valve of the present invention.
FIG. 3 is a side view partially in cross section of the flow-through cell of the present invention.
FIG. 4 is an additional side view of the flow-through cell of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For purposes of illustration, FIG. 1 of the drawings shows a flow-through cell with diverter circuit in accordance with the present invention installed in a monitoring well for withdrawing samples of groundwater using a bladder type of pump. One skilled in the art will readily recognize from the following discussion, the accompanying drawings and claims that the principles of the invention are equally applicable to fluid sampling apparatuses and pumps other than that shown in the drawings.
In FIG. 1, an exemplary fluid sampling apparatus incorporating the flow-through cell with diverter circuit of the present invention is indicated generally by reference numeral 10 and is shown for purposes of illustration as installed in a monitoring well 12, which preferably includes a well casing 14. A fluid sampling pump 20 is disposed within the well casing 14 of monitoring well 12 and is submerged beneath the water level of the groundwater 16 to a suitable depth for obtaining accurate and representative groundwater samples.
The preferred fluid sampling pump 20 is a fluid-actuated pump, wherein the actuating fluid is preferably a gas such as air, for example, and includes an inlet port 22 and an outlet port 24. A wellhead assembly 30 is secured to the well casing 14 and includes a wellhead body portion 32 having a generally horizontal support plate 34 therein. The body portion 32 substantially isolates the interior of the well 12 from the above ground surrounding environment in order to avoid or at least minimize contamination of the interior of the well which would result from the contact between the groundwater 16 and the air or other elements. The wellhead assembly 30 also includes a groundwater conduit 26 sealingly connected at one end to the pump outlet 24 and passing through plate 34 to provide direct sample delivery to a diverter valve 50. The diverter valve 50 is in turn connected to a purged water container 48 and a flow-through cell 52. The flow-through cell 52 is also connected to purged water container 48. A gas conduit 28 is connected at one end to a gas connection 36 on pump 20 and at the other end to support plate 34. Because the pump is preferably of a lightweight construction, the conduits may also be used to retain the pump in its submerged position in the well.
A controller apparatus 46, which is described in further detail in the disclosures of U.S. Pat. Nos. 4,489,779 and 4,585,060 is selectively and removably connected to the wellhead assembly 30 by means of external gas conduit 28'. The preferred controller apparatus 46 is a portable, lightweight unit and includes a source of an actuating gas and means for alternately positively pressurizing and venting or relieving the pressure of the actuating gas in order to operate the fluid sampling pump 20.
In order to further isolate the interior of the well 12 from above-ground contamination, the wellhead assembly 30 preferably includes a closure member 40 adapted to be secured to the body portion 32 by a locking pin 42 insertable through corresponding aligned apertures in body portion 32 and in closure member 40. The locking pin 42 preferably includes an aperture 44 at one end through which a padlock or other suitable locking means may be inserted in order to substantially prevent unauthorized access to the interior portions of the wellhead assembly.
The flow-through cell with diverter circuit 60 is comprised of two devices. The first is the diverter valve 50 and the second is the flow-through cell 52. The diverter valve 50 is shown in FIG. 2 and comprises a fluid body 62 having an inlet 64, two outlets 66 and 68 and a spring loaded poppet valve 70. The pump liquid discharge conduit 26 is connected to inlet 64 of diverter valve 50. Inlet 64 can be provided with a plurality of interchangeable connections to enable the diverter valve 50 to be connected to various sizes of discharge conduits 26. The first outlet 66 is connected by tubing to an inlet port 82 of flow-through cell 52. The second outlet 68 is connected by tubing to purged water container 48. In between inlet 64 and outlets 66 and 68 is the spring loaded poppet valve 70. When the pump 20 is activated, the groundwater will push against spring loaded popped valve 70 which will then open under a predetermined pressure. The opening of poppet valve 70 allows groundwater to flow from well 12 into purged water container 48 through outlet 68 and into flow-through cell 52 through outlet 66.
Diverter valve 50 is normally used in conjunction with pumps which have a relatively high flow rate of 3 to 10 gallons per minute. For pumps with lower flow rates, diverter valve 50 may be omitted and discharge conduit 26 would then go directly to input port 82.
Flow-through cell 52 is shown in FIGS. 3 and 4. Flow-through cell 52 is comprised of an inlet port 82, a housing assembly 86, a probe 88, a check valve 84 and an outlet port 90. The inlet port 82 receives groundwater from outlet port 66 of diverter valve 50 via a tubing interconnecting the ports.
Housing assembly 86 is comprised of a lower housing 92, a diffuser plate 94, a clear sight cylinder 96 and an upper housing 98. Lower housing 92, clear sight cylinder 96 and upper housing 98 are assembled as shown in FIG. 3 to define sealed chamber 100. Chamber 100 is sealed by seal 102 between lower housing 92 and clear sight cylinder 96 and by seal 104 between clear sight cylinder 96 and upper housing 98. Housing assembly 86 is held together by a plurality of latches which are released by quick release levers 105 shown in FIG. 4. To disassemble the flow-through cell 52 for cleaning all that is required is to release levers 105 by moving them to the position shown in broken line in FIG. 4.
Lower housing 92 has an inlet passage 106 which receives groundwater inlet port 82 and directs it into sealed chamber 100. Diffuser plate 94 is positioned between the outlet of passage 106 and sealed chamber 100 to allow the water to enter chamber 100 gently and evenly. Diffuser plate 94 makes sure the water traveling through sealed chamber 100 is dispersed in all directions such that all the groundwater is moving through the cell. There are no stagnant places in sealed chamber 100 where the groundwater does not move. Upper housing 98 has an outlet passage 108 which connects sealed chamber 100 with check valve 84 and outlet port 90. Outlet port 90 is connected by tubing to purged water container 48. Check valve 84 serves two basic purposes. First, pump 20 can be provided with weep holes that allow water to drain from the discharge conduit 26 when the pump is not in use. The is particularly useful to prevent freezing of the water when the monitoring site is in an area of below freezing temperatures. Check valve 84 will keep the flow through cell 10 full and checks off air so that groundwater cannot run out of the cell and back into the well through the weep holes in pump 20 between pump cycles. Second, when the sampling operation is complete and flow through cell 10 has been disconnected from the monitoring well, there will be water left in cell 10. Check valve 84 keeps water from running out of cell 10 as cell 10 is being moved from monitoring well to monitoring well. This eliminates the need to remove the cell and drain it after each sampling.
Upper housing 98 is also adapted to receive probe 88. Probe 88 is a water analyzer having a plurality of sensors or electrodes to measure various parameters of the groundwater. These sensors or electrodes could include PH electrodes, reference potential electrodes, temperature sensors, oxygen reduction potential electrodes, ion selective electrodes, conductivity electrodes, oxygen electrodes, hydrocarbon sensors, carbon dioxide sensors or any combination of these. A typical probe including a data recorder to display the analyzed results is shown in U.S. Pat. No. 4,103,179 issued Apr. 7, 1992 to Thomas et al. the disclosure of which is hereby incorporated by reference.
Probe 88 extends through an aperture 110 in upper housing 98. A retention plate 112 positions and holds probe 88 within sealed chamber 100 in the proper position. Retention plate 110 has a seal 114 to seal between probe 88 and retention plate 110. Retention plate 110 also has a seal 116 between retention plate 110 and upper housing 98 to complete the sealing of sealed chamber 100. Retention plate 110 is secured to upper housing 98 by a plurality of quick release thumb screws 118.
The apparatus operates as follows. Groundwater conduit 26 is connected to diverter valve 50. Diverter valve 50 may be attached to well casing 14 by a hanger or other means known in the art. Outlet port 66 of diverter valve 50 will be connected by tubing to inlet port 82 of flow-through cell 52. Outlet port 68 of diverter valve 50 will by connected by tubing to purge water container 48. Outlet port 90 of flow-through cell 52 will be connected by tubing to purge water container 48. The apparatus is now ready for operation.
The next step is to supply actuating gas to pump 20 thus actuating pump 20 and causing groundwater to be pumped from well 12 through diverter valve 50 into container 48. This will allow some groundwater to enter flow-through cell 52 and be discharged through outlet port 90 into container 48. The data recorder is turned on and continuous readings are recorded. When the readings of the data recorder have stabilized at acceptable levels, pump 20 is turned off, groundwater conduit 26 is disconnected from diverter valve 50, pump 20 is again turned on and the representative water sample is taken. The operation of the sampling apparatus by this method insures that the amount of purged groundwater from well 12 will be kept to a minimum.
While the above detailed description describes the preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims. | There is provided a flow-through cell with a diverter valve for continuously monitoring specific parameters of a fluid which passes through the flow-through cell. The diverter valve diverts a portion of fluid flow from a fluid line to the flow-through cell. The flow-through cell has an analyzing probe capable of monitoring a plurality of conditions of the fluid that is flow through the cell. By continuously monitoring specific parameters of the fluid as it moves through the flow-through cell, it is possible to constantly monitor the condition of the fluid and react to changes or stabilization of the readings provided by the probe. | 4 |
FIELD OF THE INVENTION
The present invention relates to telephony and to telephone instruments which have dual circuit capability.
BACKGROUND TO THE INVENTION
Most telephone networks in use at the present time are circuit switched networks, in which telephone subscribers have, at least to a local switching station, a dedicated line identified by a subscriber's number. Connection to the network is achieved by a switch closing a circuit including the subscriber line to the local switching station. Telephone calls may be conveyed from switching station to switching station by a variety of links, but connection is established for the call to the ultimate recipient by means of circuit switching controlled by the generation of pulse trains or tones representing the recipient's telephone number. Although telephone messages, whether voice calls or other types of call, such as facsimile transmissions, may be conveyed between switching stations by various time division, frequency division or even packet-switched communication links, as far as the end stations, the telephone instruments, are concerned they make connections to an analog circuit-switched network. Owing to the global nature of the existing circuit-switched networks, their use will obviously continue for many years and telephone instruments are necessarily adapted to establish connections by way of the familiar circuit-switched network.
In recent years there has been increasing use, first in local area networks and then on a wider scale, of packet-switched networks, of which the ‘Internet’ is the best known. The present invention is based on an appreciation that the usage of packet-switched networks will provide a potential alternative communication link between telephone subscribers.
The present invention envisages a new form of telephone instrument, typically a handset capable of making voice calls, which has a dual circuit capability in that it is capable of establishing a call connection over the ordinary, circuit-switched telephone network but may, if desired automatically, transfer the call connection from the circuit-switched telephone network to a packet-switched network.
SUMMARY OF THE INVENTION
An instrument according to the invention would normally possess, in common with existing instruments, some means for providing signals for transmission and some means for converting signals received by the instrument into output signals. The aforementioned means may, in the case of a telephone handset instrument, include the usual microphone and loudspeaker and the usual dialing equipment or tone generation equipment by means of which an intended recipient's number can be transmitted in the format required by the circuit-switched network to the local switching station in order to establish a call connection with an intended recipient.
An instrument according to the invention will, however, further comprise not only a switching circuit for selectively establishing and terminating a connection between the instrument and the circuit-switched telephone network but further means for selectively establishing and terminating a connection between the instrument and a packet-switched communication network. The switching circuit for this purpose may include appropriate multiplexing equipment interposed between the call generating and receiving circuits and the terminals or connection points for the telephone network and the packet-switched network.
Further, the telephone instrument preferably comprises control means including means operable to define or obtain a network address of the instrument in the packet-switched communication network, the control means being operable:
(i) to control the switching circuit to establish a call connection to another instrument on the telephone network;
(ii) in response to receipt of an acknowledgement signal including the network address of the other instrument to control the switching circuit to make the call connection to the other instrument by way of the packet-switched network.
The instrument may signal information including its network address over the initial call connection. Alternatively, it may obtain its network address only after receipt of the said acknowledgment from the other instrument.
The instrument may further comprise control means operable on receipt of a call by way of the circuit-switched network to provide an acknowledgement including the network address of the instrument, and on receipt of a subsequent message over the packet-switched network to terminate connection over the circuit-switched network.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of two telephones having dual connections;
FIG. 2 is a schematic drawing of a telephone according to the invention coupled to both a public-switched telephone network and a packet-based network;
FIG. 3 illustrates the operation of call logic at a calling station; and
FIG. 4 illustrates the operation of call logic at a called or receiving station.
DETAILED DESCRIPTION
FIG. 1 illustrates broadly the intended operation of the invention, which assumes the continued existence of the familiar circuit-switched networks. When therefore a calling instrument (hereinafter called ‘station’) needs to communicate with a second instrument (station) 2 , station 1 will initially use a circuit-switched line 3 , since there is a presumption that at least in the foreseeable future the remote station 2 will be connected to the public-switched telephone network. If however the called station 2 is connected to a packet-switched network 4 and the calling station 1 is also connected to the packet-switched network, then the call may be completed over the packet-switched network.
Whether a call should be completed over the packet-switched network 4 may be a matter of selection and programming and may also be dependent upon whether the cost of a call per unit time is cheaper or more expensive over the packet-switched network 4 than it is over the ordinary telephone line 3 which proceeds through the public-switched telephone network. It will be assumed in the following that at least the calling instrument or station 1 is configured or programmed to attempt to establish a packet-switched call connection with the remote station 2 if it is feasible to do so.
FIG. 2 illustrates a calling station 10 which includes a telephone instrument 1 comprising a familiar handset 11 and a keypad 12 . The instrument 1 is connected to a voice codec 13 which takes analog signals from the handset, digitizes them and passes the digitized data to a central processing unit (CPU) 14 . The CPU may be of the digital signal processor type. It is employed to process signals both from the handset 1 via the voice codec 13 and also a packet interface 15 and to couple signals from a PSTN interface 16 . The packet interface may be any one of a variety of packet interfaces, such as an ASDL interface or an Ethernet interface. The packet interface, in this example, transmits Ethernet packets in which the message data is constituted by voice data obtained by way of the voice codec 13 and CPU 14 from the instrument 1 .
FIGS. 3 and 4 illustrate the operation of a station 10 when operating as a calling station and a called or receiving station respectively.
In the system broadly shown in FIG. 1, and on the assumption that at least telephone 1 is disposed in a station 10 having a facility for communicating by way of the packet-switched network 4 , the operation is as follows.
User A at station 10 including instrument 1 calls a user B, having telephone 2 by means of obtaining the keypad information entered by the keypad 12 and calling via the public-switched telephone network, as shown at stages 30 and 31 of FIG. 3 . If the call did not connect (stage 32 ), a fresh attempt is made to initiate the call (stage 30 ). In any case, the CPU will collect the digits from the keypad and signal them down the PSTN interface 16 to the public-switched telephone network.
Once a circuit has been established by way of the public-switched network, users A and B will be able to talk over the circuit as in a standard telephone call. Once the call is established, the originating station will attempt to signal the receiving station to establish whether the receiving station has a packet-switched network that could be used for continuing the call. A basic signaling method that will work on all types of public-switched telephone networks is in-band with the voice signal. One method is to employ DTMF signals to send information from A to B, namely a sequence of tones along with the user's voice data which indicates to the receiving station that the sending station 10 is equipped with a secondary packet interface 14 . This is shown by stage 33 in FIG. 3 .
If the receiving station is not equipped with the logic to respond to the DTMF tones, the sending station will continue to communicate over the PSTN network, as shown by stages 35 until the call is completed (stage 36 ). If however the receiving station is equipped with the appropriate logic, it can respond to the sending station by indicating the network address on the packet network (stage 34 ). This address might be fixed and unchanging or might be assigned dynamically in some way. One known method to assign addresses dynamically is to have the station communicate to a centralized entity that will use a protocol to communicate to calling station a free address. This communication of the address (however allotted) of the receiving station B is communicated over the packet-switched network to the packet interface 15 and the CPU 14 . This is shown by stage 34 in FIG. 3 .
Once the called station has responded to the calling station with its packet network address the calling station can attempt to obtain a connection over the packet network. Using the packet network address obtained from the called station, the calling station will attempt to connect over the packet network. If the calling station can establish a connection then digitized voice data may be sent from instrument 1 by voice codec 13 and CPU 14 over the packet network. Optionally, the called station can verify the quality of the packet link to see whether it is adequate for both voice calls. The quality check may determine latency, jitter, reliability or some other attribute of the link.
Thus as shown in FIG. 3, there is establishment of the packet connection at stage 37 and the sending of voice data over the packet link (stage 38 ) until the call is completed.
With two links established, one over the circuit-switched network and one over the packet-based network, the called station can decide which route to choose. A variety of methods may be used to perform the change over from voice on the public-switched telephone network to voice data on the packet network. For example, the called station may determine when it is appropriate to switch over from the packet-switched telephone network to the packet network. The called station will analyse the voice information arriving on the packet-switched telephone network interface and wait for silence in the voice call. At this point the voice information that is arriving on the packet interface can be sent to the handset without the user being aware of the switch-over. At this point the packet-switched telephone network call can be terminated and the remainder of the call connection can continue over the packet network.
Thus, as shown in FIG. 4, the station 4 logic operates as follows.
Stage 40 indicates the rest state where the station is waiting for a call. Stage 41 indicates the answering of the call over the public-switched telephone network. Stage 42 performed in the CPU 14 requires a determination of whether the caller requested the network address of the station. If no such request was made, the call over the public-switched telephone network is continued until the call is terminated (stage 43 ).
If the caller requested the network address for the called instrument, the address is returned (stage 44 ) over the public-switched telephone network using DTMF tones or other mechanism.
If the call arrived on the packet interface from the calling IP address (stage 43 ) the call is connected over the packet network (stage 46 ). The connection quality of the packet is verified (stage 47 ) and there is a further determination to see whether the quality is acceptable for the packet voice path (stage 48 ). If the call did not arrive from the packet interface from the calling IP address or the voice quality is not acceptable for the packet voice path, the call continues over the public-switched telephone network until hang-up. If however the call did arrive on the packet-based network and the voice quality is acceptable for the packet voice path, the called station analyses the public-switched telephone network and packet data for silence (stage 49 ) and then terminates the call over the public-switched telephone network by operation of the CPU until the call is complete, when the packet connection is dropped (stage 50 ). | A telephone instrument comprises a mechanism for providing signals for transmission, a mechanism for converting signals received by the instrument into output signals, a switching circuit for selectively establishing and terminating a connection between the instrument and a circuit-switched telephone network and for selectively establishing and terminating a connection between the instrument and a packet-switched communication network. When calling, the instrument signals over the circuit-switched network for a network address for the called instrument and the packet-switched network and establishes a dual connection over the packet-switched network if such a network address is received. When receiving a call, the instrument can terminate the call connection over the circuit-switched network and continue the call by way of the packet-switched network. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional application 61/558,299, filed Nov. 10, 2011, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles that are useful for treating ovarian cancer and other types of serosal cancers.
BACKGROUND OF THE INVENTION
[0003] Ovarian cancer ranks fifth in cancer deaths among women and causes more deaths than any other gynecologic malignancy. It is estimated that in the United States 22,430 new cases will be diagnosed each year with 15,280 deaths. Ovarian carcinoma remains enigmatic in at least two important respects. First, the histological region of origin for this cancer remains obscure and second, an identifiable premalignant lesion that is generally recognized by cancer pathologists is yet to be defined. The majority (80%) of patients present with advanced stage disease with cancer cells throughout the abdominal cavity, leading directly to the high mortality (5 year survival rates 15-45%). In contrast, the survival rate for early stage disease, with malignancy confined to the ovary, is about 95%.
[0004] The median overall survival for patients with advanced ovarian cancer has improved from approximately 1 year in 1975 to currently in excess of 3 years. For subsets of patients having optimally debulked disease and receiving treatment with taxane-and platinum-based combination chemotherapy, survival now exceeds 5 years. However the disease course is one of remission and relapse requiring intermittent re-treatment. The presence of cancer cells in effusions within the serosal (peritoneal, pleural, and pericardial) cavities is a clinical manifestation of advanced stage cancer and is associated with poor survival. Tumor cells in effusions most frequently originate from primary carcinomas of the ovary, breast, and lung, and from malignant mesothelioma, a native tumor of this anatomic site. Unlike the majority of solid tumors, particularly at the primary site, cancer cells in effusions are not amenable to surgical removal and failure in their eradication is one of the main causes of treatment failure.
[0005] PCT WO2011/057034 suggests that serosal ovarian cancer stem cells (also called catena cells), which possess a glycocalyx (pericellular coat), may be the most drug resistant structure in ovarian cancer. Presumably due to the impermeability of the glycocalyx, catena cells appear resistant to many chemotherapeutic agents. It is important to discover compounds that can penetrate the glycocalyx and exert toxicity against ovarian cancer stem cells. Eradicating cancer stem cells (CSCs) would be expected to increase the efficiency of therapy for ovarian or other serosal cancers, including metastatic serosal cancer.
SUMMARY OF THE INVENTION
[0006] The compounds of the invention are useful as anticancer agents, particularly in the treatment of ovarian and other serosal cancers.
[0007] In one aspect, the invention relates to a method for inhibiting the growth of an ovarian cancer cell or other cancer cell with a pericellular coat. The method comprises exposing the cell to a compound of formula I:
[0000]
[0000] wherein:
Y is CR 1 or N; Z is CR 5 or N; R 1 is chosen from H and (C 1 -C 8 )hydrocarbon; R 2 is chosen from H, halogen, —CF 3 , —NO 2 , —CN, —NHC(═O)(C 1 -C 8 )hydrocarbon and —NHSO 2 (C 1 -C 8 )hydrocarbon; R 3 is chosen from H and halogen; R 4 is chosen from H, halogen, —NO 2 , —CN, (C 1 -C 8 )hydrocarbon and —O—(C 1 -C 8 )hydrocarbon; and R 5 is chosen from H, halogen, —NO 2 , —CN, —NHC(═O)(C 1 -C 8 )hydrocarbon and —NHSO 2 (C 1 -C 8 )hydrocarbon.
[0015] In another aspect, the invention relates to a method for treating serosal cancer in a patient having serosal cancer, said method comprising administering to said patient a therapeutically effective amount of a compound of formula I.
[0016] In another aspect, the invention relates to a compound of formula:
[0000]
[0017] In another aspect, the invention relates to a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula:
[0000]
DETAILED DESCRIPTION OF THE INVENTION
[0018] The serosal cavity is a closed body cavity that includes and encloses the peritoneal, pleural, and pericardial cavities of the body, is fluid filled (serosal fluid) and is bounded by the serous membrane. Serosal cells are any cells originating from or found within the serosal cavity or forming or attaching to the serous membrane, and include, but are not limited to, ovarian, endothelial, stomach, intestinal, anal, pancreatic, liver, lung and heart cells. Serosal cancers include the primary cancers that arise within the serosal cavity and secondary cancers that arise by metastasis of other cancer cells into the serosal cavity. Major serosal cancers at different serosal sites include those in (1) pleural effusions, namely mesothelioma, bronchogenic lung cancer, breast cancer, bladder cancer, ovarian cancer, fallopian tube cancer, cervical cancer and sarcoma; (2) peritoneal effusions, namely ovarian cancer, fallopian tube cancer, gastric cancer, pancreatic cancer, colon cancer, renal cancer and bladder cancer; and (3) pericardial effusions, namely mesothelioma, bronchogenic lung cancer, breast cancer, bladder cancer, ovarian cancer, fallopian tube cancer, cervical cancer and sarcoma. The list is not exhaustive, and other cancers that metastasize to a serosal cavity and form tumors can be considered as “serosal cancers.”
[0019] WO2011/057034 discloses a model of the catena-spheroid concept and the role of CSCs in the development of ovarian cancer. According to this model, the initial transformation of ovarian (or fallopian) epithelium progresses via an epithelial-mesenchymal and mesenchymal-catena transition. The catena cells lose all attachment to extracellular matrix or peritoneal mesothelium but remain attached to each other following each round of symmetric division. At this point, the catena is composed predominantly of CSCs. The catenae can release single cells that generate secondary catenae or form spheroids. The catenae can also roll up and form spheres which contain a >10 fold higher frequency of CSC than tumors growing as two-dimensional (2D) monolayers or solid tumors. Spheroids can release new catenae or can attach to the mesothelial wall of the peritoneum to form omental cakes. Catenae may be released from solid tumors by a mesenchymal-catena transition and may reenter the peritoneal ascites or penetrate into blood vessels leading to more distant metastasis. Hyaluronan is a major component of the glycocalyx, which is a predominant morphological feature of catenae and can be removed by treatment with hyaluronidase. The glycocalyx extends up to approximately 20 μm around the catena cells.
[0020] It has now been found that certain 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles are capable of penetrating the glycocalyx and inhibiting the growth of catena cells.
[0021] In one aspect, the invention relates to methods employing compounds of formula I:
[0000]
[0022] In some embodiments of the invention, the methods involve administration of compounds of the formula II:
[0000]
[0000] which is a subset of formula I. In these compounds, Y is N and Z is CR 5 . R 5 may be H or CH 3 . In some embodiments of subset II, R 2 and R 3 may be H. In some embodiments of II, R 4 may be H.
[0023] In other embodiments of the invention, which form another subset of the compounds of formula I, the methods involve administration of compounds of the formula III:
[0000]
[0000] In these compounds, Z is N and Y is CR 1 . In some embodiments of subset III, R 2 and R 3 may be H. In some embodiments of III, R 4 may be H.
[0024] In other embodiments of the invention, which form another subset of the compounds of formula I, the methods involve administration of compounds of the formula IV:
[0000]
[0000] In these compounds, Z is CR 5 and Y is CR 1 . In some embodiments of subset IV, R 3 may be halogen. In some embodiments, R 1 and R 3 may be H and R 2 may be halogen, —CF 3 , —NO 2 , or —CN. In some embodiments, R 1 may be (C 1 -C 8 )hydrocarbon. In some embodiments, R 2 and R 3 may be H. In some embodiments of IV, R 4 may be H.
[0025] Throughout this specification the terms and substituents retain their definitions.
[0026] Alkyl is intended to include linear or branched, or cyclic hydrocarbon structures and combinations thereof. A combination would be, for example, cyclopropylmethyl. Lower alkyl refers to alkyl groups of from 1 to 6 carbon atoms. Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, s-and t-butyl, cyclobutyl and the like. Preferred alkyl groups are those of C 20 or below; more preferred are C 8 or below. Cycloalkyl is a subset of alkyl and includes cyclic hydrocarbon groups of from 3 to 8 carbon atoms. Examples of cycloalkyl groups include c-propyl, c-butyl, c-pentyl, norbornyl and the like.
[0027] Alkoxy or alkoxyl refers to groups of from 1 to 8 carbon atoms of a straight, branched, or cyclic configuration and combinations thereof attached to the parent structure through an oxygen. Examples include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, cyclohexyloxy and the like. Lower-alkoxy refers to groups containing one to four carbons.
[0028] Aryl and heteroaryl mean a 5- or 6-membered aromatic or heteroaromatic ring containing 0-3 heteroatoms selected from O, N, or S; a bicyclic 9- or 10-membered aromatic or heteroaromatic ring system containing 0-3 heteroatoms selected from O, N, or S; or a tricyclic 13- or 14-membered aromatic or heteroaromatic ring system containing 0-3 heteroatoms selected from O, N, or S. The aromatic 6- to 14-membered carbocyclic rings include, e.g., benzene, naphthalene, indane, tetralin, and fluorene and the 5- to 10-membered aromatic heterocyclic rings include, e.g., imidazole, pyridine, indole, thiophene, benzopyranone, thiazole, furan, benzimidazole, quinoline, isoquinoline, quinoxaline, pyrimidine, pyrazine, tetrazole and pyrazole. As used herein aryl and heteroaryl refer to residues in which one or more rings are aromatic, but not all need be.
[0029] Arylalkyl means an aryl ring attached to an alkyl residue in which the point of attachment to the parent structure is through the alkyl. Examples are benzyl, phenethyl and the like. Heteroarylalkyl means an alkyl residue attached to a heteroaryl ring. Examples include, e.g., pyridinylmethyl, pyrimidinylethyl and the like.
[0030] C 2 to C 10 hydrocarbon means a linear, branched, or cyclic residue comprised of hydrogen and carbon as the only elemental constituents and includes alkyl, cycloalkyl, polycycloalkyl, alkenyl, alkynyl, aryl and combinations thereof. Examples include benzyl, phenethyl, cyclohexylmethyl, cyclopropylmethyl, cyclobutylmethyl, allyl, camphoryl and naphthylethyl.
[0031] Unless otherwise specified, the term “carbocycle” is intended to include ring systems in which the ring atoms are all carbon but of any oxidation state. Thus (C 3 -C 10 ) carbocycle refers to both non-aromatic and aromatic systems, including such systems as cyclopropane, benzene and cyclohexene; (C 8 -C 12 ) carbopolycycle refers to such systems as norbornane, decalin, indane and naphthalene. Carbocycle, if not otherwise limited, refers to monocycles, bicycles and polycycles.
[0032] Heterocycle means a cycloalkyl or aryl residue in which one to two of the carbons is replaced by a heteroatom such as oxygen, nitrogen or sulfur. Heteroaryls form a subset of heterocycles. Examples of heterocycles include pyrrolidine, pyrazole, pyrrole, imidazole, indole, quinoline, isoquinoline, tetrahydroisoquinoline, benzofuran, benzodioxan, benzodioxole (commonly referred to as methylenedioxyphenyl, when occurring as a substituent), tetrazole, morpholine, thiazole, pyridine, pyridazine, pyrimidine, pyrazine, thiophene, furan, oxazole, oxazoline, isoxazole, dioxane, tetrahydrofuran and the like.
[0033] As used herein, the term “optionally substituted” may be used interchangeably with “unsubstituted or substituted”. The term “substituted” refers to the replacement of one or more hydrogen atoms in a specified group with a specified radical. Substituted alkyl, aryl, cycloalkyl, heterocyclyl etc. refer to alkyl, aryl, cycloalkyl, or heterocyclyl wherein one or more H atoms in each residue are replaced with halogen, haloalkyl, alkyl, acyl, alkoxyalkyl, hydroxyloweralkyl, hydroxy, loweralkoxy, haloalkoxy, oxaalkyl, carboxy, nitro, amino, alkylamino, and/or dialkylamino. In one embodiment, 1, 2 or 3 hydrogen atoms are replaced with a specified radical. In the case of alkyl and cycloalkyl, more than three hydrogen atoms can be replaced by fluorine; indeed, all available hydrogen atoms could be replaced by fluorine.
[0034] The compounds described herein may contain, in a substituent R x , double bonds and may also contain other centers of geometric asymmetry; unless specified otherwise, it is intended that the compounds include both E and Z geometric isomers. Likewise, all tautomeric forms are also intended to be included. The configuration of any carbon-carbon double bond appearing herein is selected for convenience only and, unless expressly stated, is not intended to designate a particular configuration; thus a carbon-carbon double bond depicted arbitrarily herein as trans may be cis, trans, or a mixture of the two in any proportion. The compounds may also contain, in a substituent R x , one or more asymmetric centers and may thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-. The present invention is meant to include all such possible isomers, as well as their racemic and optically pure forms. Optically active (R)- and (S)-isomers may be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques.
[0035] As used herein, and as would be understood by the person of skill in the art, the recitation of “a compound” -unless expressly further limited-is intended to include salts of that compound. In a particular embodiment, the term “compound of formula I” refers to the compound or a pharmaceutically acceptable salt thereof. For example, when Y or Z is nitrogen, the compounds of the invention may exist as salts, i.e. cationic species.
[0036] The term “pharmaceutically acceptable salt” refers to salts whose counter ion (anion) derives from pharmaceutically acceptable non-toxic acids including inorganic acids and organic acids. Suitable pharmaceutically acceptable acids for salts of the compounds of the present invention include, for example, acetic, adipic, alginic, ascorbic, aspartic, benzenesulfonic (besylate), benzoic, boric, butyric, camphoric, camphorsulfonic, carbonic, citric, ethanedisulfonic, ethanesulfonic, ethylenediaminetetraacetic, formic, fumaric, glucoheptonic, gluconic, glutamic, hydrobromic, hydrochloric, hydroiodic, hydroxynaphthoic, isethionic, lactic, lactobionic, laurylsulfonic, maleic, malic, mandelic, methanesulfonic, mucic, naphthylenesulfonic, nitric, oleic, pamoic, pantothenic, phosphoric, pivalic, polygalacturonic, salicylic, stearic, succinic, sulfuric, tannic, tartaric acid, teoclatic, p-toluenesulfonic, and the like.
[0037] It will be recognized that the compounds of this invention can exist in radiolabeled form, i.e., the compounds may contain one or more atoms containing an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Alternatively, a plurality of molecules of a single structure may include at least one atom that occurs in an isotopic ratio that is different from the isotopic ratio found in nature. Radioisotopes of hydrogen, carbon, phosphorous, fluorine, chlorine and iodine include 2 H, 3 H, 11 C, 13 C, 14 C, 15 N, 35 S, 18 F, 36 Cl, 125 I, 124 I, and 131 I respectively. Compounds that contain those radioisotopes and/or other radioisotopes of other atoms are within the scope of this invention. Tritiated, i.e. 3 H, and carbon-14, i.e., 14 C, radioisotopes are particularly preferred for their ease in preparation and detectability. Compounds that contain isotopes 11 C, 13 N, 15 O , 124 I and 18 F are well suited for positron emission tomography. Radiolabeled compounds of formulae I and II of this invention and prodrugs thereof can generally be prepared by methods well known to those skilled in the art. Conveniently, such radiolabeled compounds can be prepared by carrying out the procedures disclosed in the Examples and Schemes by substituting a readily available radiolabeled reagent for a non-radiolabeled reagent.
[0038] Although this invention is susceptible to embodiment in many different forms, preferred embodiments of the invention are shown. It should be understood, however, that the present disclosure is to be considered as an exemplification of the principles of this invention and is not intended to limit the invention to the embodiments illustrated. It may be found upon examination that certain members of the claimed genus are not patentable to the inventors in this application. In this event, subsequent exclusions of species from the compass of applicants' claims are to be considered artifacts of patent prosecution and not reflective of the inventors' concept or description of their invention; the invention encompasses all of the members of the genus I that are not already in the possession of the public, and all of the members of the genus I for use in treating cancer where such use is not already in the possession of the public.
[0039] While it may be possible for the compounds of formula I to be administered as the raw chemical, it is preferable to present them as a pharmaceutical composition. According to a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula I or a pharmaceutically acceptable salt or solvate thereof, together with one or more pharmaceutically carriers thereof and optionally one or more other therapeutic ingredients. The carrier(s) must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. The compositions may be formulated for oral, topical or parenteral administration. For example, they may be given intravenously, intraarterially, intraperitoneally, intratumorally or subcutaneously.
[0040] Formulations include those suitable for oral, parenteral (including subcutaneous, intradermal, intramuscular, intravenous and intraarticular), rectal and topical administration. The compounds are preferably administered orally or by injection (intravenous, intramuscular, intraperitoneally, intratumorally or subcutaneous). The precise amount of compound administered to a patient will be the responsibility of the attendant physician. However, the dose employed will depend on a number of factors, including the age and sex of the patient, the precise disorder being treated, and its severity. Also, the route of administration may vary depending on the condition and its severity. The formulations may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pharmacy. In general, the formulations are prepared by uniformly and intimately bringing into association the active ingredient with liquid carriers or finely divided solid carriers or both and then, if necessary, shaping the product into the desired formulation.
[0041] Formulations of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous liquid or a non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented as a bolus, electuary or paste.
[0042] A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredient in a free-flowing form such as a powder or granules, optionally mixed with a binder, lubricant, inert diluent, lubricating, surface active or dispersing agent. Molded tablets may be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide sustained, delayed or controlled release of the active ingredient therein.
[0043] Formulations for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient. Formulations for parenteral administration also include aqueous and non-aqueous sterile suspensions, which may include suspending agents and thickening agents. The formulations may be presented in unit-dose or multi-dose containers, for example sealed ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of a sterile liquid carrier, for example saline, phosphate-buffered saline (PBS) or the like, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.
[0044] Preferred unit dosage formulations are those containing an effective dose, as herein below recited, or an appropriate fraction thereof, of the active ingredient.
[0045] It should be understood that in addition to the ingredients particularly mentioned above, the formulations of this invention may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavoring agents.
[0046] As used herein, “treatment” or “treating,” or “palliating” or “ameliorating” are used interchangeably herein. These terms refer to an approach for obtaining beneficial or desired results including but not limited to therapeutic benefit and/or a prophylactic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated. Also, a therapeutic benefit is achieved with the eradication or amelioration of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the patient, notwithstanding that the patient may still be afflicted with the underlying disorder. For prophylactic benefit, the compositions may be administered to a patient reporting one or more of the physiological symptoms of a disease, even though a diagnosis of this disease may not have been made.
[0047] A comprehensive list of abbreviations utilized by organic chemists (i.e. persons of ordinary skill in the art) appears in the first issue of each volume of the Journal of Organic Chemistry . The list, which is typically presented in a table entitled “Standard List of Abbreviations” is incorporated herein by reference.
[0048] The compounds employed in the invention are commercially available, are known or may be synthesized by processes known in the art. For example, U.S. Pat. Nos. 5,514,699; 5,281,619; and 5,507,762 as well as European patent 537949 describe the synthesis of numerous 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles. The disclosures of U.S. Pat. Nos. 5,514,699; 5,281,619 and European patent 537949 as they relate to the synthesis of 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles are incorporated herein by reference. In general the synthesis may be schematically described as follows:
[0000]
[0049] Ten examples of compounds of the genus I have been prepared and tested according to the protocol described in WO02011/057034, which is recapitulated here. Ovcar3-GTL-derived catenae were tested for their ability to self-propagate in flat bottom 384-well microtiter plates (Corning). Cultures of Ovcar3-GTL catenae were mechanically or enzymatically dissociated to single cells. For mechanical dissociation, catena cultures were pipetted vigorously, an equal volume of M5-FCS media was added to decrease the viscosity, and the cells were pelleted. For enzymatic dissociation, catena cultures were incubated at 5 mg/ml collagenase IV (Invitrogen) for 10 min at 37° C. followed by centrifugation to pellet the cells. Cells were resuspended in M5-FCS to produce homogenous cultures of single cells which were seeded in 50 microliter aliquots per well at the indicated cell densities and grown for 6 days before addition of test compounds or other reagents.
[0050] To assess cell growth, cells were observed under the microscope and manually counted using a hematocytometer or were treated with alamarBlue by adding 1/10 volume of alamarBlue reagent directly to the culture medium, incubating the cultures for a further 48 hours at 37° C. and measuring the fluorescence or absorbance. Both spectroscopic methods gave comparable results. The amount of fluorescence or absorbance is proportional to the number of living cells and corresponds to the cells metabolic activity. Fluorescence measurement is more sensitive than absorbance measurement and is measured by a plate reader using a fluorescence excitation wavelength of 540-570 nm (peak excitation is 570 nm) and reading emission at 580-610 nm (peak emission is 585 nm). Absorbance of alamarBlue is monitored at 570 nm, using 600 nm as a reference wavelength. Larger fluorescence emission intensity (or absorbance) values correlate to an increase in total metabolic activity from cells.
[0051] Because the components of the pericellular glycocalyx were significantly removed prior to cell seeding by mechanical or enzymatic dissociation of catena, the optimal time for adding compounds to ensure that the catenae had an established glycocalyx is 3-6 days after seeding. In WO2011/057034 it was shown that catena were resistant to 21 out of 23 known anticancer agents. The formation of glycocalyx conferred more than 8,000,000-fold resistance in catenae to paclitaxel, fludelone and 9-10dEpoB. All 10 of the 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles described below were found active in this screen, indicating that, unlike most known anticancer agents, the 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitriles are able to penetrate the glycocalyx.
[0052] Compounds tested and found effective were:
[0000]
[0053] The compound designated example 4 above was tested in vivo for toxicity in NSG mice. As used herein, NSG and NSG mice mean the NOD scid gamma (NSG) mice, or an equivalent, available from The Jackson Laboratory and which are the NOD.Cg-Prkdc scid Il2rg tm|wjl /SzJ JAX® Mice strain. The NSG mice were injected intraperitoneally with 1, 2.5, 5, 10, 20 or 40 mg/kg of the compound designated example 4 above for once or three times a week for 4 weeks. The compound designated example 4 above showed no overt toxicity in any concentrations or at any drug administration schedules. | Methods for inhibiting the growth of ovarian cancer cells or other serosal cancer cells are disclosed. The method involves exposing the cells to a 2-amino-4H-naphtho[1,2-b]pyran-3-carbonitrile of formula:
whereinY is CR 1 or N and Z is CR 5 or N. | 2 |
This is a divisional application of Ser. No. 09/848,842, filed May 4, 2001, now allowed as U.S. Pat. No. 6,384,271.
FIELD OF THE INVENTION
The invention relates to a process for sulfonating, sulfating, or sulfamating an organic compound.
BACKGROUND OF THE INVENTION
Sulfonation of organic compounds represents a major synthetic reaction. Sulfonations commonly use sulfuric acid and sulfur trioxide as the sulfonating agents. While sulfur trioxide presents major problems in terms of corrosivity, toxicity, and the consequences of leakage, it provides certain advantages. For example, sulfonation with sulfur trioxide can result in different and advantageous ratios of sulfonated isomers compared with the use of sulfuric acid and avoid safety problem with handling sulfuric acid.
The importance of the ratio of sulfonated isomers is conveniently described by the synthesis of p-cresol, extensively used in disinfectants and in the manufacture of resins. The sulfonation of toluene provides essentially a mixture of o- and p-toluene sulfonic acids, which are fused with sodium hydroxide to yield the corresponding o- and p-cresols (o- and p-methylphenols). Since the o-cresol is largely an unwanted byproduct, maximizing the ratio of para:ortho is highly advantageous in terms of ease of purification of the desired p-cresol, minimizing byproduct and waste streams, and minimizing energy use in the purification steps. The term regiospecificity is used to describe the ability of, in this application, a sulfonating agent, to affect the para:ortho ratio.
The sorption of sulfur trioxide by some basic organic compounds is well known. For instance, certain polyvinylpyridine resins form addition compounds with sulfur trioxide that can be used in sulfation reactions. See U.S. Pat. No. 3,057,855 disclosing use of a sulfur trioxide-poly(2-vinylpyridine) polymer for sulfation. See also W. Graf, in Chemistry and Industry, p 232, 1987 disclosing a pyridine-sulfur trioxide complex bound to a cross-linked polystyren for the sulfation of alcohols and amines. However, the sulfur trioxide is sufficiently deactivated in the complexes that it does not sulfonate aromatics. Furthermore, U.S. Pat. No. 4,490,487 discloses SO 3 adducts with imides and the use of the adducts as sulfonating agents for aromatic compounds.
In all such complexes or adducts, SO 3 is deactivated. Some deactivate SO 3 enough that they become somewhat unreactive to sulfonate compounds that are relatively resistant to sulfonation. For instance, the sulfur trioxide-pyridine complexes described above have uses limited to the sulfation of alcohols, sugars, polysaccharides, etc.
It would be desirable to develop new sulfur trioxide complexes in which the sorbent is substantially insoluble to facilitate product isolation, which sulfonate aromatic compounds in a regiospecific manner, and which provide a more active solid sulfonating, sulfating, and sulfamating agent effective in a wider range of sulfonation, sulfation, and sulfamation processes.
An advantage of the invention is that it can be used industrially for the manufacture of detergents, dye intermediates, and sulfonated oils. For example, detergents can be made by using the SO 3 complexes disclosed below for either sulfating alcohols or sulfonating polyalkyl benzenes. Another advantage is that the use of the SO 3 complexes provides substantial safety and product isolation advantages over the prior art.
SUMMARY OF THE INVENTION
A process comprises contacting an organic compound with sulfur trioxide under a condition sufficient to effect the sulfonation, sulfation, or sulfamation of the organic compound in which the organic compound is selected from the group consisting of an aromatic compound, alcohol, carbohydrate, amine, amide, protein, and combinations of two or more thereof; and the sulfur trioxide is present in a complex comprising an inorganic support selected from the group consisting of zeolite, silicalite, silica, titanosilicate, borosilicate, clay, and combinations of two or more thereof.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention, any organic compounds that can be sulfurized with SO 3 can be used. The term “sulfurized” refers to being added a sulfur atom or sulfur-containing functionality. Examples of suitable organic compounds include, but are not limited to, aromatic compounds, alcohols, carbohydrates, amines, amides, proteins, or combinations of two or more thereof.
The aromatic compound is preferably an activated aromatic compound. An activated aromatic compound has no substituents on the arylene ring or contains at least one electron-donating group on the arylene ring. Examples of electron-donating groups include alkyl, alkoxy, alkylthio, hydroxy, amino, amide such as —NHCOCH 3 , phenyl, or combinations of two or more thereof. Specific examples of activated aromatic compounds include, but are not limited to, benzene, naphthalene, biphenyl, toluene, aniline, benzylamine, methylaniline, dimethylaniline, diphenylamine, triphenylamine, anisidines, acetanilide, benzanilide, toluidine, phenol, hydroxymethyl benzene, biphenyl, or combinations of two or more thereof. Many of these compounds such as, for example, aniline, benzylamine, methylaniline, dimethylaniline, toluidine, phenol, and hydroxymethyl benzene can also be sulfated or sulfamated. The presently preferred aromatic compound is toluene. See generally, Everett Gilbert, in “Sulfonation and Related Reactions”, Interscience Publishers, John Wiley and Sons, 1965, p. 65.
The process of the invention is also useful for selectively sulfonating an aromatic compound. The term “selective or selectively” used herein, unless otherwise indicated, refers to the sulfonation of suitable aromatic compound to produce substantially higher para:ortho ratio. Such selective sulfonation is also referred to as improving “regiospecificity”, which is disclosed in the BACKGROUND OF THE INVENTION section.
For example, with sulfonation of toluene using the invention process, the toluene sulfonic acid produced has an enhanced para:ortho ratio. Also, sulfonation of biphenyl, biphenyl-4-sulfonic acid production is enhanced. Further for example, selective sulfonation suppresses undesired multiple sulfonations in reactive aromatic compounds such as naphthalene.
Wishing not to be bound by theory, the mechanism for the regiospecificity is believed to be due to steric restrictions for a reaction within the inorganic support or sorbent pores. The pore dimensions are believed to orient the organic molecule as it contacts the sulfur trioxide. For instance, in the sulfonation of biphenyl, the biphenyl enters the pore constrained or oriented to present the 4-position to the reactant SO 3 . The pore dimension creates a constraint against presentation of the 2-position to the sorbed reactant; a constraint that is absent in conventional fluid phase reactions.
The preparation of p-cresol via the sulfonation of toluene and subsequent alkali metal hydroxide fusion discussed above is an example of sulfonation, which improves regiospecificity of the sorbed sulfur trioxide. The higher ratio of p-toluene sulfonic acid to o-toluene sulfonic acid results in a higher yield of the desired p-cresol and reduced isolation costs. A second example is the sulfonation of biphenyl, to give a sulfonation more regiospecific in the production of the preferred biphenyl-4-sulfonic acid, a source of various 4-substituted biphenyl compounds, including 4-phenylphenol.
Any alcohols that are substantially liquid or are soluble in an inert solvent under ambient conditions can be used. Examples of suitable alcohols include, but are not limited to, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, octanol, decanol, or combinations of two or more thereof.
Any carbohydrates that are substantially soluble in a solvent, which is inert to SO 3 such as super critical CO 2 , can be used in the invention. Examples of suitable carbohydrates include, but are not limited to, glucose, fructose, sucrose, or combinations of two or more thereof.
Similarly, proteins suitable for use in the invention are substantially soluble in an inert solvent. Examples of suitable proteins also include peptides containing the repeat units of (C(O)N(R)) n where R is hydrogen or a hydrocarbyl radical having 1 to about 10 carbon atoms per radical; and n can be a number from 2 to about 30.
Any amines and amides that can be sulfonated or sulfamated can be used in the invention. Examples of suitable amines include, but are not limited to, methylamine, ethylamine, propylamine, dimethylamine, ethylenediamine, tetraethylenediamine, ethanolamine, isobutylamine, those aromatic amines disclosed above, or combinations of two or more thereof.
Examples of suitable amides include, but are not limited to, acetamide, acrylamide, benzamide, formamide, propionamide, butyramide, valeramide, stearamide, succinimide, those aromatic amides disclosed above, or combinations of two or more thereof.
The organic compounds disclosed herein can be used in the presence of a solvent, if needed. A suitable solvent is inert to SO 3 and the organic compound. Suitable solvents can include, but are not limited to, methylene chloride, perfluorooctane, 1,2-dichloroethane, nitrobenzene, and liquid or supercritical carbon dioxide, or combinations of two or more thereof.
Sulfur trioxide can be incorporated into or supported on an inorganic support to produce a SO 3 -inorganic support complex (hereinafter referred to as SO 3 complex) by any means known to one skilled in the art such as, for example, impregnation, sorption, or combinations thereof. The presently preferred method is a sorption process in which SO 3 is sorbed into the support.
The term “sorbed” used herein refers to a composition of an inorganic support and SO 3 exhibiting a partial vapor pressure of SO 3 less that of sulfur trioxide itself, e.g., at 24° C. a partial vapor pressure of less than about 0.3 atmosphere (29 kPa).
The SO 3 complexes can be produced by sorbing sulfur trioxide into or onto an inorganic support. Any fluid containing 1 to about 100 weight % SO 3 can be used. The fluid can be gas, liquid, or combinations thereof such as nitrogen or SO 3 , if pure is SO 3 used, and the preferred purity is from about 98 to 100%. Any source of SO 3 of adequate purity can be used, typically a container of pure liquid SO 3 is used. The SO 3 , as vapor or liquid, is passed at a preferred temperature range of 35° C.-90° C. through a bed of an inorganic support to produce a SO 3 complex. The inorganic support can be heated up to 150° C. during the sorption or optionally heated and then cooled to increase sorption. The sorption process can be carried out with a suitable inorganic support in any suitable container or vessel inert to SO 3 . Steel or stainless steel cylinders, which can be lined with an inert lining such as poly(tetrafluoroethylene), are preferred. Optionally an inert carrier gas may be used to move the sulfur trioxide into the sorbent. In a typical sorption step, for instance, dry nitrogen can be passed through liquid sulfur trioxide maintained at about 20° C. to about 50° C., preferably about 35° C., to provide a stream containing about 50% by volume of SO 3.
The term “inert fluid or gas” refers to a fluid or gas that is unreactive with SO 3 , support, or container, such as nitrogen. When an inert gas is used, the purity of the SO 3 is described exclusive of the carrier gas. Optionally SO 3 can be sorbed under a positive pressure to accelerate sorption.
Sulfur trioxide suitable for use in the invention can be incorporated in or supported on an inorganic support. Examples of such inorganic supports include, but are not limited to, zeolites, silicalites, silicas, titanosilicates, borosilicates, clays, aluminophosphates, or combinations of two or more thereof.
Molecular sieves, both natural and synthetic, are well known in the art. See, e.g., R. Szostak, Molecular Sieves—Principles of Synthesis and Identification, Van Nostrand Reinhold (1989). The inorganic molecular sieves used for incorporating or supporting sulfur trioxide include various silicates (e.g., titanosilicates, borosilicates, silicalites, low alumina-containing zeolites such as mordenite and ZSM-5, and high alumina-containing zeolites such as 5A, NaY and 13X). The preferred molecular sieves are either acidic or are non-acidic silicates.
Zeolites are available from various sources. A comprehensive listing of zeolites vendors is contained in “CEH Marketing Research Report: Zeolites” by M. Smart and T. Esker with A. Leder and K. Sakota, 1999, Chemical Economics Handbook-SRI International.
Examples of suitable zeolites include, but are not limited to, mordenite, Y, X, 5A, US-Y, DA-Y, ZSM-5, ZSM-11, beta, L, ferrierite, and clinoptilolite. Examples of suitable titanosilicates are TS-1, TS-2, and Ti-beta. Examples of suitable clays are montmorillonite, kaolin, and talc. Examples of suitable borosilicates are boralite-A, boralite-B, boralite-C, and boralite-D. Examples of suitable aluminophosphates are AIPO 4 -5, SAPO-5, AlPO 4 -11, SAPO-34, and combinations of two or more thereof. Silicas include precipitated silica, dried silica, diatomaceous earth, silica gels, and fumed silicas. See also Kirk-Othmer Encyclopedia of Chemical Technology, 3 rd edition, volume 115 (John Wiley & Sons, New York, 1991) and W.M. Meier and D.H. Olson, “Atlas of Zeolite Structure Types”, 3 rd edition (Butterworth-Heineman, Boston, Mass. 1992).
The pore dimensions that control access to the interior of the zeolite are determined not only by the tetrahedra forming the pore opening, but also by the presence or absence of ions in or near the pore. In the case of zeolite A, for example, access can be restricted by monovalent ions, such as Na + or K + , which are situated in or near 8-ring openings as well as 6-ring openings. Access is enhanced by divalent ions, such as Ca 2+ , which are situated only in or near 6-ring openings. Thus, the potassium and sodium salts of zeolite A exhibit effective pore openings of about 0.3 nm and 0.4 nm respectively, whereas the calcium salt of zeolite A has an effective pore opening of 0.5 nm. For this application it is important that the pore opening be of sufficient size (at least 0.5 nm) to allow the ingress and egress of sulfur trioxide. The presence or absence of ions in or near the pores, channels, and/or cages can also significantly modify the accessible pore volume of the zeolite for sorbing materials. To maximize capacity, generally protons or small cations are preferred.
Preferred inorganic supports include high surface area silicas and high silica-containing molecular sieve materials (Si/Al greater than about 5.1) prepared either by synthesis or modification. These materials include silicalite, mordenite, beta, US-Y, DA-Y, ZSM-5, ZSM-11, borosilicates, titanosilicates and the like. The most preferred materials have a Si/Al ratio of at least about 25. Those with Si/Al ratios in the range from about 1 to about 4.4 can also be used. The amount of sulfur trioxide incorporated or supported is at least about 1%, preferably at least about 3%, and most preferably at least about 5% by weight, based on the weight of the supports. The maximum amount is dependent upon the physical structure of the support used, typically in the range from about 40% to about 60% based on the weight of the support.
Because these inorganic supports are well known to one skilled in the art, the description of which is omitted herein for the interest of brevity.
Preferably, the support is in a pelletized, beaded, or extruded and chopped form to facilitate gas or liquid flow through. It can be pelletized, beaded, or extruded using a suitable binder, which is stable to exposure to sulfur trioxide and the sorption/desorption conditions, using any means well known to one skilled in the art. Gamma-alumina, silica, and clays are examples of suitable binders.
The processes of sulfonation and sulfation can be carried out by any means known to one skilled in the art such as that disclosed in detail in “Sulfonation and Sulfation” in The Encyclopedia of Chemical Technology, 4th edition, Wiley Interscience Publication, John Wiley & Sons, New York N.Y., 1997. Both are methods for the introduction of the SO 3 group into organic compounds. In sulfonation, the SO 3 group is introduced to produce a sulfonate, where the SO 3 group is bound directly to a carbon atom, yielding a C—SO 3 —X structure. X can be hydrogen, a metal (sulfonate salt), or halogen (sulfonyl halide). Sulfonation of toluene with sulfur trioxide, as an example, yields toluene sulfonic acid isomers. In sulfation, the SO 3 group is introduced to produce a sulfate, where the SO 3 group is bound though an oxygen atom to a carbon atom, yielding a C—O—SO 3 —X group. For example, sulfation of an alcohol with sulfur trioxide yields the alcohol sulfate. Sulfamation is the sulfonation of the R 2 NH group in amines, amides, and proteins to form a R 2 NSO 3 H group.
The organic compound to be sulfonated, sulfated, or sulfamated can be contacted with a SO 3 complex under a condition sufficient to sulfonate, sulfate, or sulfamate the organic compound. The organic compound can be present as a fluid, vapor, liquid, solution, or combinations thereof both, with or without a solvent disclosed above or in a carrier gas such as nitrogen. For example, sulfonation using the SO 3 complexes can be carried out by heating the organic compound alone or in an inert solvent with the SO 3 complex to effect reaction. Any of the solvents disclosed above (methylene chloride, perfluorooctane, 1,2-dichloroethane, nitrobenzene, and liquid or supercritical carbon dioxide) can be used. The condition can include a temperature in the range of from about 0 to about 100° C., preferably 20 to 60° C., under a pressure that can accommodate the temperature range for a period of time in the range of from about 1 to about 100 hours, preferably 10 to 50 hours. The molar ratio of sorbed SO 3 to the organic compound can be in the range from about 0.01:1 to about 100: 1, preferably 1:10 to 10:1. An excess of organic compound can be used to function as a solvent. An excess of the sorbed SO 3 can be used where it is desirable to force complete reaction of the organic compound. A ratio of about 1:1 is generally preferred in a continuous pipeline counter-current reactor.
When the sulfonation, sulfation, or sulfamation is complete, the product can be isolated conventionally. For instance, the residual inorganic sorbent or support is filtered off, washed with water, and the filtrate extracted with sufficient amount of water to remove the sulfonated, sulfated, or sulfamated product. The sulfonated, sulfated, or sulfamated product can be isolated from the combined extracts conventionally by any means known to one skilled in the art and water can be removed to isolate the product.
EXAMPLES
Example 1
This example shows the sulfonation of toluene using a silica gel/SO 3 complex.
A sample (20 g) of silica gel (Grade 952, a silica gel from Davison Division of W. R. Grace, Baltimore Md.) was placed in a quartz tube in a vertically mounted tube furnace, heated by raising the temperature 60° C. per hour to 600° C. and holding at 600° C. (the drying temperature) for 5 hours under flowing nitrogen. The sample was cooled under flowing nitrogen and then transferred to a dry box. This procedure was repeated as necessary and dried material from each run was combined and mixed thoroughly.
A polytetrafluoroethylene (PTFE) vessel was loaded with 32.6 g (initial weight) of the dried silica gel and heated to 60° C. Distilled SO 3 vapor (at 44° C.) was purged over the solid for 2 hours. The solid was then heated to 78° C. under a dry nitrogen purge for 11.5 hours to remove surface bound SO 3 . The final weight of the silica gel/SO 3 complex was 36.4 g (11.5% weight gain, 10.4% SO 3 loading). The silica gel/SO 3 complex was then transferred under anhydrous conditions to the thermogravimetric analysis (TGA) where on average it lost 9.4% of its weight between room temperature and 350° C.
The silica gel/SO 3 (5.0 g, containing 7.5 mmol sulfur trioxide, sorbant quantity/mmol SO 3 ) was added to toluene (50.0 g, substrate/weight) under nitrogen in a 100-ml round bottomed flask equipped with overhead stirrer and condenser. The solution was then heated to 50° C. for 20 hours (reaction temperature/time). The solution was cooled to room temperature and the silica gel support was filtered from the solution. The gel was washed with 10 ml hot water (60° C.) and the toluene was extracted with the same water solution. The water was analyzed by high pressure liquid chromatography (HPLC) and shown to contain 29% yield p-toluenesulfonic acid (TSA), 4% o-TSA, and 0.7% m-TSA (ratio p/o =7.3) for a total 33.7% yield (product % yield) based on the SO 3 in the complex.
Examples 2-11
Examples 2-11 were carried out similarly as Example 1. Experimental details of all Examples are shown in Table 1. Product details of these Examples are shown in Table 2. In Table 1, the sorbents and sources are as follows. Examples 1, 9, 10, and 11: silica gel (Grade 952, a silica gel from Davison Division of W. R. Grace, Baltimore, Md.); Examples 2 and 8: silicalite (S-115), from Union Carbide, New York, N.Y.; now UOP, Des Plaines, Ill.; Example 3: H-Beta (SiO 2 /Al 2 O 3 =25) (CP 811BL-25, H-beta (SiO 2 /Al 2 O 3 =25), PQ Corp., Valley Forge, Pa. Example 4: high silica Y-zeolite (CBV-901, a H-SDUSY zeolite (SiO 2 /Al 2 O 3 =150) from Zeolyst International, Valley Forge, Pa. Example 5: H-ZSM-5 zeolite (SiO 2 /Al 2 O 3 =150), from Conteka, Leiden, Netherlands, now Zeolyst International, Valley Forge, Pa.); Example 6: H-ZSM-5 zeolite (SiO 2 /Al 2 O 3 =300) from PQ Corp., Valley Forge, Pa., and Example 7: Zeolite 5A (Molecular Sieve Type 5A), from Linde Division, Union Carbide, New York N.Y., now UOP, Des Plaines, Ill.
TABLE 1
Experimental Detail for Examples 1-11
Catalyst Utilization (see Table 2 for
Ex.
SO 3 Sorption
product detail)
#
Sorbent 1
T 2
W 3
G/L 4
WL 5 .
S/W 6
Q 7
R 8
Y 9
1
Silica
600
32.6/36.4
11.7/10.4
9.4
T/50
5.0/7.5
50/20
TSA/33.7
2
Silicalite
500
5.0/5.9
18.0/15.3
15.2
T/75
3.2/6.0
50/20
TSA/35.9
3
H-beta
500
5.5/6.62
20.4/16.9
13.7
T/75
3.4/6.0
50/20
TSA/38.9
4
Y-zeolite
500
3.0/4.3
43.3/30.2
29.1
T/50
2.0/7.3
50/20
TSA/25.5
5
H-ZSM-5
500
30.7/33.9
10.4/9.4
14.1
T/50
5.0/8.8
50/20
TSA/30.7
6
H-ZSM-5
500
30.1/33.1
10.0/9.1
9.0
T/50
5.0/5.6
50/20
TSA/30.9
7
Zeolite 5A
500
10.5/11.4
8.6/7.9
8.8
T/50
3.99/7.5
50/20
TSA/53.9
8 10
As Ex. 2
T/2
2.52/6.8
40/20
TSA/41.1
9 11
As Ex. 1
B/3.9
5.3/6.3
RT/22
BPS/29.7
10
As Ex. 1
600
20.0/23.9
19.5/16.3
17.4
M/20
2.5/6.25
RT/1
MSA/68.5
11
As Ex. 1
Bu/20
2.5/6.25
RT/1
BSA/82.4
1 See listing at Example 1 for sources & specifications.
2 T, drying temp. for 5 h (° C.)
3 W, initial weight/final weight (g)
4 G/L, SO 3 gain/load (%)
5 WL, weight Loss to 350° C. (%)
6 S/W, substrate or reactant in grams;
T, toluene;
B, biphenyl;
M; methanol;
Bu, butanol.
7 Q, SO 3 /sorbant Quantity (g)/mmol SO 3
8 R, reaction temperature/time (° C./h);
RT: room temperature.
9 Product % yield;
TSA: toluene sulfonic acid isomers;
BPS: biphenyl 4-sulfonic acid;
MSA: methyl sulfate;
BSA: n-butyl sulfate.
10 Example 8 used toluene (2 g) dissolved in dry methylene chloride (25 g) and was refluxed at 40° C. The product was extracted with acetonitrile instead of water.
11 Example 9 used biphenyl (3.9 g) dissolved in dry methylene chloride (50 g).
Comparative Example A
This example shows sulfonation of toluene using 98% sulfuric acid
Sulfuric acid (1.0 g, 10.2 mmol) was added to toluene (50.0 g) under the same conditions as Example 1. The analysis by HPLC showed 26% yield p-toluenesulfonic acid, 11% o-toluenesulfonic acid, and 1.3% m-toluenesulfonic acid (ratio p/o=2.4) for a total yield of 38.3%.
Comparative Example B
This example shows sulfonation of toluene using sulfur trioxide.
Sulfur trioxide (0.6 g, 7.5 mmol, stabilized, 99% from Aldrich, Milwaukee, Wis.) was weighed into a 100-ml round-bottom flask in the dry box. Toluene (50 g) was added to the sulfur trioxide via syringe under an inert atmosphere. The solution was stirred at 50° C. for 22 hours under a nitrogen atmosphere before it was cooled to room temperature. A dark colored oil formed at the bottom of the solution. The toluene and oil layer was extracted with three 10-cc portions of distilled water. The analysis by HPLC showed 28% yield of p-TSA and 5.5% o-TSA (ratio p/o=5.1) for a total yield of 33.5%.
Comparative Example C
This example illustrates preparation of silica gel/H 2 SO 4 complex and demonstrates that sulfonation is not effective with a sulfuric acid complex.
As described in the literature [F. Chavez et al, Synthetic Communications, 24(16), 2325-2339(1994)], silica gel (10 g), sulfuric acid (1.20 g), and acetone (50 g) were stirred in a 100 ml round bottom flask equipped with condenser, magnetic stirrer, and thermocouple at room temperature for 2 hours. The acetone was removed under vacuum and the silica gel was removed under vacuum at 80° C. The TGA analysis showed 1.44 mmol H 2 SO 4 /g silica.
Silica gel/H 2 SO 4 complex prepared as described above (5.0 g, 7.2 mmol) was added under nitrogen to dried toluene (50 g) in a 100-ml round-bottom flask equipped with a magnetic stirrer, condenser, gas inlet, thermocouple, and heating mantle. The solution was heated to 50° C. for 18 hr., cooled to room temperature, and filtered. The toluene was extracted with three 10-ml portions of water. The insoluble support was placed into the thimble of a Soxhlet Extractor with 100-ml water and extracted for 48 hours. The combined water extracts were analyzed by HPLC and shown to contain 0.9% p-TSA, 0.01% o-TSA, and trace m-TSA for a TSA total yield of 0.9%.
Comparative Examples D and E
These examples show that silicalite/SO 3 reacts with other solvents such as acetonitrile and tetrahydrofuran.
Comparative Example D was prepared in the same way as Example 8 using the silicalite/SO 3 complex prepared as in Example 2, but used dried acetonitrile (50 g) rather than methylene chloride. The HPLC analysis showed 4.2% p-TSA, 0.52% o-TSA, and 0.1% m-TSA for a total TSA yield of 4.8%. Only small amounts of sulfur (1.6%) were left in the zeolite by x-ray fluorescence elemental analysis, indicating complete reaction of the sulfur trioxide.
Comparative Example E was prepared in the same way as Example 8 using the silicalite/SO 3 complex prepared as in Example 2, but used dried tetrahydrofuran (50 g) rather than methylene chloride. The HPLC analysis showed 4.8% p-TSA, 1.2% o-TSA, and 0.09% m-TSA for a total TSA yield of 6.1%. Only small amounts of sulfur (0.9%) were left in the zeolite by x-ray fluorescence elemental analysis indicating complete reaction of the sulfur trioxide. The gas chromatography/mass spectrometric analysis also showed that tetrahydrofuran was sulfonated.
The results of the examples and comparative examples are shown in Table 2.
TABLE 2
Comparison of Isomer Yields and Ratios
Toluene Sulfonic Acid Isomers
p:o ratio improvement
Example
Ortho
Meta
Para
Yield
p:o
factor vs. Comp.
(solvent)
(o)
(m)
(p)
(%)
ratio
Example A
Examples
1
4.0
0.7
29
33.7
7.3
3.0
2
1.8
0.1
34
35.9
18.9
7.9
3
4.0
0.7
34.2
38.9
8.6
3.6
4
6.6
0.5
18.4
25.5
2.8
1.2
5
3.9
0.4
26.4
30.7
6.8
2.8 (0.7% sulfone)
6
1.9
0.2
28.8
30.9
15.2
6.3
7
7.7
0.7
45.5
53.9
5.9
2.2
8 (CH 2 Cl 2 )
9.6
1.3
30.2
41.1
3.1
1.3 (0.04% sulfone)
Comparative Examples
A
11.0
1.3
26
38.3
2.4
—
B
5.5
*
28.0
33.5
5.1
C
0.01
*
0.9
0.9
Poor yield
D
0.52
0.1
4.2
4.8
Poor yield
(CH 3 CN)
E
1.2
0.09
4.8
6.1
Poor yield
(THF**)
* Trace of isomer detected but in less than a quantifiable concentration.
** THF, Tetrahydrofuran.
Table 2 shows substantially enhanced para/ortho ratios for the sulfonation of toluene to toluene sulfonic acid using the invention process. | A process that can be used for sulfonating, sulfating, or sulfamating an organic compound is disclosed. The process can comprise, consist essentially of, or consist of, contacting the organic compound with sulfur trioxide under a condition sufficient to effect the sulfonation, sulfation, or sulfamation of the organic compound. The organic compound can be an aromatic compound, alcohol, carbohydrate, amine, amide, protein, or combinations of two or more thereof. The sulfur trioxide can be present in a complex comprising an inorganic support such as zeolite, silicalite, silica, titanosilicate, borosilicate, clay, aluminophosphate, and combinations of two or more thereof. | 2 |
RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application 61/835,932 filed on Jun. 17, 2013, entitled “System And Method For Providing On The Fly Updates of Threat And Hazard Information Through A Mobile Application”, the entirety of which is incorporated herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to the field of mobile applications. More specifically to using mobile applications to promote threat awareness.
[0004] 2. Description of the Related Art
[0005] The use of mobile phones has grown dramatically from a device simply capable of making and receiving calls into a device capable of performing a plethora of non-call making/receiving related functions. These non-call making/receiving functions are usually accomplished through the use of mobile applications. Although there are countless mobile applications designed to perform these non-call making/receiving related functions, there is a need for mobile applications that are capable of promoting threat awareness.
[0006] Unfortunately, schools, offices and public venues around the world are becoming a target to foreign and domestic terrorism. There are not enough law enforcement officers available to secure every location where a terrorist or terrorist organization may attack. Currently, information relevant to a threat is generic and disseminated in broadcast form. Such information is typically from news and information sources, is disseminated after some delay, and is focused on a general location applicable to a wide audience. However, those in close proximity of the threat need immediate information, need assistance on ways to best protect themselves and other innocent people, and don't want it broadcast widely.
[0007] Therefore, what is needed is a system with a user interface that is flexible and user friendly, and which can promote threat awareness by providing a tool that notifies people, such as employees, within an organization when a threat is identified, as well as on the fly update of where threats have been identified for the purpose of planning escape routes.
SUMMARY OF THE INVENTION
[0008] This summary of the invention is provided to introduce concepts in a simplified form that are further described in the detailed description of the invention. This summary is not intended to identify key or essential inventive concepts of the claimed subject.
[0009] The present invention provides a system, method, and solution for the promotion of threat awareness, notification to employees within an organization or individuals within a location when a threat is identified, and on the fly updates of where threats have been identified for the purposes of planning escape routes. An organization or the location could be Schools, Offices, Sports Arenas, or other Public Venues where people congregate such as Movie Theaters, Train Stations, Airports, and Shopping Malls (collectively hereinafter referred to as an “organization”). The threat and hazard response system uses various processors, servers, software, and communication devices in combination with mobile applications on smart phone devices, such as Android and iPhone devices, to provide relevant threat information.
[0010] The threat and hazard response system provides a mobile application in combination with various servers, processors, computing devices and networks to provide organizations with threat and hazard information, in addition to providing similar information to first responders who can be used to plan escape routes and aid in rescues. The threat and hazard response system provides teachers, employees, maintenance staff, grounds keepers, etc. with information in which to assist the user keep their organization safe. The information may be provided in one or more software modules within the mobile software application and may provide information such as a map of the building, escape or exit routes, as well as provide information on various safety checks and reports. The system may allow users to “LOOK” and identify things that seem out of the norm, or “REPORT” incidents in a timely and accurate manner, and “RESPOND” to active threats if your organization, campus, or workplace becomes engaged by a threat or crisis situation.
[0011] Users in an organization that utilize the threat and hazard response system make use of the mobile application on their smartphone devices such as Android and iPhone devices. The mobile application and related system software is designed such that in an emergency, the more personnel within the organization and response network that are aware of the situation the better the opportunity for more information to be shared. Thus, more real time information is available to provide an accurate picture of the situation. The response network includes police, fire and rescue, and other local and national authorities that may be involved in the response.
[0012] All users of the threat and hazard response system mobile app have to do is identify their organization and their building's blueprint and layout can be identified, and the system will incorporate that information into what will become the layout or a main user interface screen of the mobile application. The user interface of the threat and hazard response system mobile app is flexible and extremely user friendly.
[0013] The system of the present invention utilizes a zone based identification rather than specific rooms. Users of the threat and hazard response system mobile app are able to tap a Zone on their own floor plan and send out one of several alerts based on the severity of the threat. The primary or initial three alert types are: All Clear, Suspicious Activity or Immediate Threat. Other “super” authorized users of the system within the organization will be notified and will be able to see on their mobile phones all the alerts on their floor plan maps. Users within a school or organization who touch an alert on the screen of their mobile phone will be presented with information regarding that alert such as the timestamp of when the alert was posted, as well as the user who made the alert. Based on the severity of the threat, certain users will be able to immediately dial 911 from within the threat and hazard response system mobile app or have the app contact 911 automatically.
[0014] These and other objects, features, and/or advantages may accrue from various aspects of embodiments of the present invention, as described in more detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Various exemplary embodiments of this invention will be described in detail, wherein like reference numerals refer to identical or similar components or steps, with reference to the following figures, wherein:
[0016] FIG. 1 depicts a system diagram of the present invention;
[0017] FIG. 2 depicts a user interface screen showing the map and zone function of the present invention;
[0018] FIG. 3 depicts a user interface screen showing the panic timer function of the present invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0019] Particular embodiments of the present invention will now be described in greater detail with reference to the figures. Like reference numerals apply to similar parts throughout the several views. The embodiments presented here are not meant to be exhaustive. Other embodiments using the concepts introduced in the present invention are possible. In addition, the components in these embodiments may be implemented in a variety of different ways.
[0020] As seen in FIG. 1 , the present invention can provide a threat notification system 100 where the user of the threat and hazard response system mobile app on their mobile device 110 can create one of several alerts to notify others of a perceived threat. The mobile device 110 can be a mix of Android and/or iOS devices or a Blackberry or a Windows mobile smartphone. The three alert types are: All Clear, Suspicious Activity, and Immediate Threat. The alert created by the mobile device 110 is communicated to the Cloud 120 via communication path 112 . The communication may be through Wi-Fi, network carrier of the mobile device, or a combination of any such paths. The alert is then transmitted to the Secured School Safety Server Network 130 via communication path 122 . The communication may be through a router, Wi-Fi, Bluetooth, NFC, any other mechanism, or a combination of any such paths. The Secured School Safety Server Network then communicates the alert to the External Push Notification Service (EPNS) 140 via communication path 114 . The communication may be through an Internal Push Notification Management Server. EPNS 140 communicates the alert to mobile devices 102 , 104 , 106 via communication paths 116 , 118 , 120 . The communication may, for example, be through Google Cloud Messaging.
[0021] In one embodiment of the present invention, the user of the threat and hazard response system mobile app on their mobile device 110 that notifies others of a perceived threat must be within the pre-determined Geo-Fence Zone. Administrators of the system may define the perimeter of the event via Geo-Fence mapping. The zone may include the building, stadiums, practice fields and all other locations considered part of the campus. Geo-Location features detect devices within the event grounds, allowing designated users to post alerts only while they are within the Geo-Fence boundaries. Administrators can define their own range of alert posting criteria to ensure that alerts are handled according to their security priority and protocol. The GPS location of any registered users device 102 , 104 , 106 , 110 can be tracked within the Geo-Fence perimeter using wireless carrier towers, Wi-Fi, or radio signals.
[0022] When the system 100 is notified that there is an active emergency, the system 100 will send a push notification to the user's mobile device 102 , 104 , 106 . Users with an Android mobile device that contains Google Cloud Messaging will receive an automatic push notification regardless as to whether the system's mobile app is in the foreground, background or inactive. This message will be passed from the system's EPNS 140 via communication paths 116 , 118 , 120 as raw JSON data into the mobile app's background service. Users will have the option to allow the mobile app to post a notification to the notification bar and/or initiate a synchronization action where the real-time information will be upload to the mobile app regarding the present emergency.
[0023] If the user has an iOS mobile device 102 , 104 , 106 with Apple Push Notification Service, the alert notification method will depend upon whether the mobile app is in the background, foreground, or inactive. If the mobile app is not in the foreground, the system 100 will display the notification informing the user that updated information is available via an alert, icon badge number, and/or sound. This alert can be displayed as an alert message or can badge the mobile app icon when new information is received. In addition to the visual notification, the system can alert the user by playing a sound to inform him or her that new information has been received. The user can tap the action button, thus launching the application, in order to provide the user the newly updated information. If the mobile app is running in the foreground when the notification is delivered, the user will receive a local or push notification based upon the pre-determined preferences set by that user. For example the user can elect that the notification be in the form of a banner or an alert message.
[0024] The system 100 also has the capability to override the mobile device's current settings. For example, when there is an active emergency with apparent life threatening conditions, the application may override the device's 102 , 104 , 106 silent or vibrate setting so that the user will hear the alert. This override capability will be automatically activated unless the user opts out through the mobile app's internal settings page.
[0025] In an alternative embodiment of the present invention, the system can utilize the government's alert network, the Wireless Emergency Alerts system, to disseminate emergency messages to the user's mobile device located within the zone of an emergency. These notifications can come as an SMS message, telephone call or a push notification.
[0026] As seen in FIG. 2 , users of the present invention, such as for example within a school or organization, will be notified and will be able to see on their mobile smartphones all the alerts on their floor plan maps. As the alerts become old, they will fade off of the zone map. Fading is based on two factors: Alert Type and Organization Preference. In terms of alert types, for example, all clear alerts should fade faster than suspicious activity alerts, and suspicious activity alerts should fade faster than immediate threat alerts. In terms of organization preference, organizations will be able to define a factor in determining when alerts fade. The idea of fading or aging an alert is used to ensure that information is kept current, and not stale.
[0027] Users with the mobile devices 102 , 104 , 106 who touch an alert on the screen of their mobile device will be presented with information regarding that alert created by the user of mobile device 110 such as the timestamp of when the alert was posted, and the user who made the alert. If the alert created by the user of mobile device 110 is Suspicious Activity, users with mobile devices 102 - 106 will receive a “Buzz,” i.e., their phone vibrates twice to alert them that something may be going on, without causing undue attention to others. Only the user with mobile device 110 who created the alert, or anyone in the “Emergency Contact” role can disable suspicious Activity alerts.
[0028] However, if the alert created by the user of mobile device 110 is an Immediate Threat alert, users with mobile devices 102 , 104 , 106 will receive a continuous “Buzz,” i.e., their phone vibrates, or repeats on periodic intervals, until acknowledged, so as to make all personnel aware that a situation has been identified. Users with mobile devices 102 , 104 , 106 that have been assigned to the “Emergency Contact” role will receive a popup notification on the screen of the mobile device with a button to immediately dial 911. The popup notification will contain as much information as is possible such as the timestamp of when the Immediate Threat was identified, the user with the mobile device 110 who made the Immediate Threat alert, and the zone the Immediate Threat was identified in. Only users with the mobile devices 102 , 104 , 106 who are assigned to the “Emergency Contact” role can remove Immediate Threat alerts.
[0029] Users of mobile devices 110 , 102 , 104 , and 106 will also have access to various menu options that provide local emergency contact information, threat and hazard response system information, and information about how to respond. Local emergency information will consist of information such as the local police department, the fire department, and EMS. The threat and Hazard response system information contains general reference information about the threat and hazard response system such as the product version, support information, and related information.
[0030] In addition to the three alerts option (All Clear, Suspicious Activity, and Immediate Threat), the user of mobile device 110 who initiates an alert will also have access to a one-touch icon that starts a PANIC timer, as seen in FIG. 3 , and converts the app into Panic Mode. The PANIC timer is defined by the school or organization. The timer can be cancelled only by the user with mobile device 110 who created it. Once the timer reaches ZERO, an Immediate Threat alert is dispatched to mobile devices 102 , 104 , 106 without zone information so as to not provide information to any illicit individual(s). Users with mobile devices 102 , 104 , 106 will receive a popup on the screen of their mobile device with the name of the user of the mobile device 110 who activated the PANIC timer. The threat and hazard response system app then locks itself on the “Help & Information” screen. This lock mechanism is designed to prevent the illicit individual(s) who pose or caused the hazard or threat from getting a hold of a device that has been placed in panic mode and being able to see the location of other users of the threat and hazard response system with devices 102 , 104 , 106 within the organization. The lock mechanism also prevents the illicit individual(s) from being able to see that the device has been placed into a panic mode. Unlocking the threat and hazard response system app from the panic mode requires a specific feature such as uninstalling and reinstalling of the threat and hazard response system app, or specific touch and swipe gestures on the help screen. The panic mode serves two very important purposes: it provides a method that requires almost no interaction, i.e., once a timer has been started, the user of the mobile device 110 who initiated the panic timer can either drop, pocket, hide, or ignore the device. In addition, the panic mode alerts the users of mobile devices 102 , 104 , 106 that someone is in PANIC mode, thus making everyone aware and able to start taking action such as making alerts based on their surroundings. Implementation of the timer is useful in case a user accidentally enters Panic Mode because if the app is open, having a one-touch panic mode can create too many false alarms that could be costly to an organization. The timer allows the user to “set it and forget it” in the event of a threat, or provides an added protection in that it notifies a user who accidentally set off panic mode, and the user can cancel the timer prior to it reaching ZERO, thus preventing a false alarm. Another feature particular to the timer is that it causes the panic mode screen to gradually fade to black as it counts down to ZERO. Allowing the panic mode screen to gradually fade to black helps to prevent incidents where bad guys may see the panic mode hit. Black also serves as an added incentive in that it will not draw attention to mobile devices 102 , 104 , 106 since the screen will slowly stop being lit up. In addition, once the screen completely fades to black, the threat and hazard response system app automatically switches to the “Help & Information” screen, and that is the only functionality that is still enabled. The “Home” and “Panic” tab are both removed. At this point, the threat and hazard response system app appears to be nothing more than an informative application, and appear as harmless as possible to the illicit individual(s) who created or pose the threat.
[0031] The present invention may use global positioning satellite (GPS) information to tag alerts with as accurate a location as possible. Further, a way to conserve battery life, the system may only begin getting an update of the immediate threat information when the user is on the home screen or on the Panic Mode screen, and update that information only if it is older than a preset time period (i.e. 2 minutes). The system may use the GPS coordinates to attempt to automatically locate which zone the user is in. The system may also use the GPS and client calibrated information to attempt to place the user on a specific floor at the organization, based on the altitude information returned from the GPS.
[0032] The system may also make use of an audio recording feature available within the mobile device which may be activated when an Immediate Threat is identified-or-Panic Mode is enabled, the device will automatically begin recording via the built in microphone. The audio recording from the device within the Geo Fence will be simultaneously uploaded on-the-fly directly to the cloud-based server, thus creating a “black box” that can allow administrators, first responders, local authorities, attorneys, courts, and other parties to review information from the scene without the user having to take any additional action.
[0033] The system may also make use of a video recording feature available within the mobile device which may be activated via one button or automatically when an Immediate Threat is identified-or-Panic Mode is enabled. The video is simultaneously uploaded on-the-fly to the cloud-based server, once again allowing for further evidence regarding the incident to be made available. For example, video of the emergency event can be streamed from a registered device within the Geo Fence to the Crisis Watch Center, to first responders, district administrators and other authorized users.
[0034] The system utilizes or makes available to its users the floor plans of their organization. The system can then overlay planned evacuation routes for each zone onto the map. The display of this information could be similar to the emergency exit notification lights in airplanes or direction routes provide on typical web based applications such as www.mapquest.com. This allows for the user to make best judgment call on which evacuation route to take based on identified threat information. In one embodiment, the system can utilize Google maps and layer the evacuation route datasets and other pertinent datasets onto the map.
[0035] The system also employs a rescue me mode for instances in which the user becomes trapped. The “Rescue Me” mode activates the GPS on limited time basis (to conserve battery) until an accurate location is established. The rescue mode then has the device 102 , 104 , 106 notify the server 180 and other users of the location of the device of the user in need of rescue. In a preferred embodiment, once the location of the device is obtained (within 10 meters), further GPS updates are not needed as it is assumed the user is not moving very far. The system can also activate a flashlight or strobe light mode (if device has a built-in camera with a flash) for limited periods of time.
[0036] The system of the present invention is capable of receiving events that request the device to make audible noise such that if the user is no longer conscious an administrator can remotely make the device sound out an alarm to notify rescue crews of the device's location. The concept of a “beacon” analogy where the device now provides the rescue crew information about the location of the device, therefore the person having the device, even when the person is unable to respond and take any action on their own. A key advantage of the information being published to the server is that even if the device runs out of battery and is no longer able to provide beacon information, the server can provide that information to the rescue personnel.
[0037] The system may also employ a Web Based (non-mobile) Command and Control operation system that allows administrators control over the application on all of their user's devices. The system would be able to deactivate the application and prevent it from sending or receiving any further notifications—such as in the event the device falls into the wrong hands. The system has the ability to request GPS location of individual users or all users overlaid on the school's geo-fence and well as the ability to unlock devices that have been locked down due to Panic Mode. Furthermore the system has the ability to track first responder vehicles to assist with infiltration and staging activities.
[0038] The system can further integrate the backend servers to other services such as the National Weather Service to receive local updates regarding storms and severe weather conditions. Therefore, the system using the application's built-in notification system can send National Weather Service alerts directly to the device.
[0039] The system 100 can further provide training and preparedness drills for users. Through the system 100 , schools can carry out specialized training drill on a yearly, quarterly or monthly basis. These drills may include first responders and emergency personnel.
[0040] The examples provided herein are merely for the purpose of explanation and are in no way to be construed as limiting of the present method and product disclosed herein. While the invention has been described with reference to various embodiments, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Further, although the invention has been described herein with reference to particular means, materials, and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention expands to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may affect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention.
[0041] It will be recognized by those skilled in the art that changes or modifications may be made to the above-described embodiment without departing from the broad inventive concepts of the invention. It is understood therefore that the invention is not limited to the particular embodiment, which is described, but is intended to cover all modifications and changes within the scope and spirit of the invention. | The invention provides for a mobile application based solution that promotes threat awareness by utilizing existing blueprints and layout of a building. Users of the system who identify a threat can use the system to notify others within the school or organization of the threat and the location of the threat, as well as use the system to contact local authorities. These on the fly updates of where threats have been identified can be used in planning escape routes. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a United States Non-Provisional Utility Patent Application claiming the benefit of Italian Patent Application Number TO2012A000651 filed on 25 Jul. 2012, which is incorporated herein in its entirety.
TECHNICAL FIELD
The present invention relates to a hub-bearing assembly for a tilling disc.
BACKGROUND ART
As is well known, tilling discs are usually mounted rotatably on respective spindles projecting from the frame of a plough or other agricultural machine.
WO 2002/019791 A discloses a hub-bearing assembly for rotatably mounting a tilling disc about an axis of rotation. The assembly comprises an annular hub having an axially extended tubular portion defining a generally cylindrical housing and a radially outer flange for fixing to a disc. In the housing is mounted a bearing unit comprising an outer ring, one or two inner rings and a dual set of rolling elements interposed between the outer and inner rings. In other solutions, the outer ring of the bearing is integrated into the flanged hub, forming therewith a single piece.
During use, impacts suffered by the disc against stones and similar damage the raceways of the bearing and shorten its working life.
It is therefore an object of the invention to create a hub-bearing assembly for a tilling disc capable of remedying the above-mentioned disadvantage.
DISCLOSURE OF INVENTION
It is therefore an object of the invention to create a hub-bearing assembly for a tilling disc capable of remedying the above-mentioned disadvantage.
This and other objects and advantages, which will be better understood hereafter, are achieved according to an aspect of the invention by a hub-bearing assembly for rotatably mounting a tilling disc about an axis of rotation, the hub-bearing assembly comprising:
an annular hub including:
an axially extending tubular portion defining a generally cylindrical housing, and a radially outer flange for mounting a disc;
a bearing unit mounted within the housing and comprising an outer ring, a pair of inner rings and a dual set of rolling elements, interposed between the outer ring and the inner rings; and an elastic damping body arranged in the housing and radially interposed between the hub and the outer ring of the bearing unit.
Other advantageous features are defined in the dependent claims.
Briefly, the hub-bearing assembly comprises an elastic damping body radially interposed between the hub and the outer ring of the bearing unit. The elastic damping body absorbs part of the dynamic stresses coming from impacts of the disc against stones. These stresses, no longer being fully transferred to the bearing and its rolling elements, do not noticeably damage the raceways. According to some preferred embodiments, the relative movements between the bearing unit and the housing formed from the hub for the bearing are limited due to the forced mounting of the elastic body between the bearing and the hub and owing to particular shapes taken by the outer surface of the outer bearing ring and by the housing of the hub in which the bearing unit is accommodated by means of the interposition of the elastic damping body.
BRIEF DESCRIPTION OF DRAWINGS
A description will now be given of a few preferred, but not limiting, embodiments of the invention. Reference is made to the attached drawings, in which:
FIG. 1 is a view in axial section of a tilling disc mounted rotatably about a spindle by means of a hub-bearing assembly according to an embodiment of the invention;
FIG. 2 is a perspective view of the disc with the hub-bearing assembly and spindle of FIG. 1 ; and
FIG. 3 is an enlarged view, in partial axial section, of the hub-bearing assembly and spindle of FIG. 1 .
DETAILED DESCRIPTION
Making reference now to the drawings, a hub-bearing assembly according to an embodiment of the invention, indicated in its entirety 10 , serves for mounting a disc A in freely rotatable manner about an axis of rotation x defined by a spindle B projecting in cantilever from a machine or an agricultural implement (not illustrated), such as for example a plough, a harrow or similar. The characteristics of the disc A, which may be of any known type, for example a disc for ploughing or a disc for sowing (suitable for opening furrows in a previously ploughed terrain), are not significant for the purposes of understanding the present invention and will therefore not be described here in detail.
The assembly 10 comprises a hub 20 , a bearing unit 30 housed in the hub 20 and an elastic damping body 40 interposed between the hub and the bearing unit.
The hub 20 , of overall annular form, has an axially extended principal tubular portion 21 , which defines within itself a generally cylindrical housing 22 for the bearing unit 30 . The housing 22 is delimited radially by a substantially cylindrical inner wall 22 a , described below. Throughout the present description and in the claims, the terms and expressions indicating positions and orientations such as “radial” and “axial” are to be taken to refer to the central axis of rotation x of the bearing unit 30 .
From a first axial end of the tubular portion 21 of the hub there extends a radially outer flange 23 having a plurality of axial bores 24 for mounting the disc A. From a second axial end of the tubular portion 21 there extends a radially inner flange 25 which axially delimits the housing 22 on the side further from the disc.
The bearing unit 30 is a bearing unit of the so-called first generation, i.e. without radially projecting flanges. The bearing unit 30 comprises a rotatable outer ring 31 , a pair of inner rings 32 , 33 mounted side by side on the spindle B and a dual set of rolling elements 34 , 35 , in this example balls, interposed between the outer ring 31 and the inner rings 34 , 35 . The rotatable outer ring 31 has a substantially cylindrical radially outer wall 31 a , more fully described below. Referring to FIG. 3 , the first axial end of the outer ring 31 is the end closest to the disc 10 , and, the second axial end of the outer ring 31 is the end furthest from the disc 10 .
The inner rings 32 , 33 are axially locked in position against a shoulder C on the spindle by means of a spacer D forcefully fitted onto the spindle, which is preloaded through a ring-nut (not illustrated) according to a per se known arrangement. Preferably, inner ring 32 extends axially outwardly past the first axial end of the outer ring.
The inner flange 25 extends radially towards the spindle, and provides a radial surface 25 a for abutting a radial surface 31 c of the outer ring 31 of the bearing. In the embodiment illustrated, the flange 25 further forms an annular recess 26 , facing towards the bearing, suitable for accommodating a sealing device schematically indicated E, designed to slide against the spacer D or against another element integral with the spindle B in order to hermetically seal the housing 22 of the bearing towards the outside. The annular recess 26 of the inner flange 25 may extend over the entire radial side of the sealing device.
The elastic damping body 40 allows the disc A to elastically absorb the impacts which it receives during use, and to limit damage, undesired movements and the appearance of play which the bearing unit may undergo as a result of impacts transmitted by the disc.
The elastic damping body 40 is comprised of a tubular sleeve of elastomeric material, radially interposed between the substantially cylindrical wall 22 a of the housing 22 and the radially outer surface 31 a of the outer ring 31 of the bearing.
In a preferred embodiment, the elastic body 40 is fabricated at a preliminary stage, for example by extrusion or hot forming, and is then forcibly introduced (cold pressed) into a cylindrical gap located between the surfaces 22 a and 31 a , after the bearing unit has been introduced into the housing 22 .
The elastic body 40 has a tubular wall 41 having a radial thickness which, in the undeformed condition, i.e. before the introduction of the body 40 between the walls 22 a and 31 a , is preferably greater than a dimension or radial distance which separates the surface 31 a from the wall 22 a . Due to this arrangement, the elastic body 40 remains elastically compressed in radial directions between the housing 22 of the hub and the outer bearing ring 31 .
According to an alternative embodiment, the elastic body 40 is fabricated by injecting elastomeric material in the fluid state into the cylindrical gap located between the surfaces 22 a and 31 a , after the bearing unit has been introduced into the housing 22 .
In the illustrated embodiment, the elastic body 40 has an axial length greater than the axial length of the outer ring 31 of the bearing, so as to ensure an elastic damping effect on the bearing unit for stresses transmitted thereto by the hub according to any direction or angle. Preferably, the elastic body 40 extends axially outwardly past the first and second axial ends of the outer ring.
To allow a uniform elastic response, the radial thickness of the tubular wall 41 is preferably constant. In order to guarantee correct positioning of the elastic body 40 , an annular groove 27 is formed in the housing 22 . The annular groove 27 extends into the inner flange 25 at the axial end of the wall 22 a located, in use, further from the disc A. The annular groove 27 steadily accommodates an edge 42 of the elastic body 40 . One axial end of the elastic damping body 40 may be free of abutment.
Preferably, the wall 22 a is not perfectly cylindrical but has a protrusion projecting in a radially inner direction, in this example a protrusion 22 b in the form of an annular ridge, suitable for favoring a steady axial positioning of the elastic body 40 with respect to the housing 22 and the hub 20 . In this example, the protrusion 22 b is shaped as an annular ridge which extends circumferentially around the substantially cylindrical inner wall 22 a . In the particular embodiment illustrated, also the radially outer surface 31 a of the outer ring 31 is not perfectly cylindrical but provides a radial recess 31 b preferably in the form of an annular channel or groove extending circumferentially, with the object of favoring a stable relative axial positioning of the elastic body 40 with respect to the bearing unit. In order to maintain a uniform level of compression in the body 40 , it is preferable that the radial protrusion 22 b and the radial recess 31 b should be aligned in a same radial plane, so as to maintain a constant radial distance between the facing surfaces 22 a and 31 a . Advantageously, the protrusion 22 b is located in an axially intermediate position between two radial planes P 1 , P 2 in which lie the two sets of rolling elements 34 , 35 .
In a preferred embodiment, the annular groove 31 b is formed in a particularly convenient manner if the outer ring 31 is fabricated starting from steel tube cut and subjected to cold rolling so as to form the annular groove 31 b . The specific form illustrated of the annular groove 31 b is not to be considered limiting, since grooves of different profile, for example of square profile, can also be effective for axially locking the outer ring 31 . The material of the damping body 40 , being elastically deformable, makes it possible to adapt the shape of the body 40 to that of the annular groove 31 b.
In a preferred embodiment, the elastic damping body 40 is axially retained between the hub and the outer ring of the bearing simply as a result of the elastic compression to which the body 40 is subjected, without necessitating further retaining means, such as for example the application of adhesive. The elastic damping body 40 is held even more stably as a result of the protrusion 22 b , which generates a further radial compression stress, favoring the axial retention of the elastic body 40 .
It is to be understood that the invention is not limited to the embodiments here described and illustrated, which are to be considered examples of the assembly; it will be clear to experts in the field that various changes may be made to the functions and configuration of the elements described in the exemplary embodiment, without departing from the scope of the invention as defined in the attached claims and their equivalents. | A hub-bearing assembly is disclosed, wherein the hub-bearing assembly is used for rotatably mounting a tilling disc about an axis of rotation is disclosed. The hub-bearing assembly comprises an annular hub comprising an axially extending tubular portion defining a cylindrical housing and an outer flange for mounting a disc, a bearing unit mounted in the housing, and an elastic damping body arranged in the housing and radially interposed between the hub and an outer ring of the bearing unit. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE
[0001] The present U.S. Utility Patent Application claims priority pursuant to 35 U.S.C. §120, as a continuation of U.S. application Ser. No. 14/035,607 entitled “Client Configuration During Timing Window” filed Sep. 24, 2013, which is a continuation of U.S. application Ser. No. 13/190,053 entitled “Method and System for Exchanging Setup Configuration Protocol Information in Beacon Frames in a WLAN” filed Jul. 25, 2011, issued as U.S. Pat. No. 8,572,700 on Oct. 29, 2013, which is a continuation of U.S. application Ser. No. 11/208,081, entitled “Method and System for Exchanging Setup Configuration Protocol Information in Beacon Frames in a WLAN,” filed Aug. 18, 2005, issued as U.S. Pat. No. 7,987,499 on Jul. 26, 2011, which claims priority pursuant to 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/602,396 filed Aug. 18, 2004 and to U.S. Provisional Patent Application No. 60/671,120 filed Apr. 14, 2005, all of which are hereby incorporated herein by reference in their entirety and made a part of the present U.S. Utility Patent Application for all purposes.
[0002] This application makes reference to:
[0003] U.S. application Ser. No. 11/207,302 filed Aug. 18, 2005, issued as U.S. Pat. No. 7,996,664 on Aug. 9, 2011;
[0004] U.S. application Ser. No. 11/207,262 filed Aug. 18, 2005, issued as U.S. Pat. No. 7,653,036 on Jan. 26, 2010;
[0005] U.S. application Ser. No. 11/207,658 filed Aug. 18, 2005;
[0006] U.S. application Ser. No. 11/208,310 filed Aug. 18, 2005;
[0007] U.S. application Ser. No. 11/208,275 filed Aug. 18, 2005;
[0008] U.S. application Ser. No. 11/208,346 filed Aug. 18, 2005;
[0009] U.S. application Ser. No. 11/207,661 filed Aug. 18, 2005;
[0010] U.S. application Ser. No. 11/207,301 filed Aug. 18, 2005, issued as U.S. Pat. No. 7,343,411 on Mar. 11, 2008;
[0011] U.S. application Ser. No. 11/208,284 filed Aug. 18, 2005; and
[0012] U.S. application Ser. No. 11/208,347 filed Aug. 18, 2005, issued as U.S. Pat. No. 7,930,737 on Apr. 19, 2011.
[0013] All of the above referenced applications are hereby incorporated herein by reference in their entirety and for all purposes.
FIELD OF THE INVENTION
[0014] Certain embodiments of the invention relate to wireless network communication. More specifically, certain embodiments of the invention relate to a method and system for exchanging setup configuration protocol information in beacon frames in a WLAN.
BACKGROUND OF THE INVENTION
[0015] Currently, with some conventional systems, setting up a wireless network generally requires significant interaction and technical knowledge on the part of a user setting up the network, especially when the user is configuring security options for the network. For computer savvy users, the tasks associated with setting up a wireless network may be time consuming. However, for inexperienced computer users, the tasks associated with setting up a wireless network may be more challenging and consumes significantly greater time than required by computer savvy users.
[0016] In general, 802.11-based networks require a significant amount of user interaction during the configuration process. Typically, with conventional 802.11-based networks, the user needs to configure a station (STA) to associate to an access point (AP), which may require a number of settings to be selected on the STA, and some knowledge of the default configuration of the AP. The user may then access an HTML-based menu on the new AP in order to set various configuration parameters, many of which are difficult for novice and for intermediate users to understand and set correctly. New APs generally start with a configuration that provides no network security, and which utilize a default network name (SSID) that is selected by the manufacturer such as, for example, “Manufacturer Name”, “Default”, or “wireless”. With the proliferation of 802.11 networks, users often experience confusion and network problems when their new AP uses the same SSID as a neighboring AP. In order to facilitate communication between access points and access devices such as wireless STAs, various protocols are required. While the 802.11 WLAN standard provides a basis for implementing WLAN, it lacks various features that may be utilized to address the confusion, network problems and issues that users face when, for example, their new AP uses the same SSID as a neighboring AP.
[0017] Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0018] A method and system for exchanging setup configuration protocol information in beacon frames in a WLAN, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.
[0019] These and other advantages, aspects and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0020] FIG. 1 is a block diagram of an exemplary wireless network, which may be utilized in connection with an embodiment of the invention.
[0021] FIG. 2 is a block diagram of an exemplary system for wireless data communications comprising an ESS with collocation of configurators and access points (AP), in accordance with an embodiment of the invention.
[0022] FIG. 3 is a diagram illustrating exemplary message exchanges based on a configuration protocol and initiated at the configurator, in accordance with an embodiment of the invention.
[0023] FIG. 4 is a diagram illustrating exemplary message exchanges based on a configuration protocol and initiated at the client station, in accordance with an embodiment of the invention.
[0024] FIG. 5 a is a block diagram for an exemplary beacon frame format, in accordance with an embodiment of the invention.
[0025] FIG. 5 b is a block diagram for an exemplary beacon frame body format, in accordance with an embodiment of the invention.
[0026] FIG. 6 a is a block diagram for an exemplary IEEE 802.11 information element format, in accordance with an embodiment of the invention.
[0027] FIG. 6 b is a diagram of an exemplary configuration protocol information element, in accordance with an embodiment of the invention.
[0028] FIG. 6 c is a diagram of an exemplary configuration protocol data field format, in accordance with an embodiment of the invention.
[0029] FIG. 7 a is a diagram of an exemplary configuration protocol packet header format, in accordance with an embodiment of the invention.
[0030] FIG. 7 b is a diagram of an exemplary EAP header message format for a configuration protocol, in accordance with an embodiment of the invention.
[0031] FIG. 7 c is a diagram of an exemplary EAP header body format for a configuration protocol, in accordance with an embodiment of the invention.
[0032] FIG. 7 d is a diagram illustrating an exemplary configuration protocol packet type key format, in accordance with an embodiment of the invention.
[0033] FIG. 7 e is a diagram illustrating an exemplary configuration protocol packet type info format, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Certain aspects of a method for enabling exchange of information in a secure communication system may comprise configuring at least one 802.11 client station via authentication enablement information comprising data that specifies a time period during which configuration is allowed. The data that specifies a time period during which configuration is allowed may comprise a configuration window open field, which indicates a period when a configuration setup window is open. At least one client station may be configured via the authentication enablement information comprising recently configured data, which indicates whether at least one configurator has configured at least one other client station within the time period during which the configuration is allowed.
[0035] FIG. 1 is a block diagram of an exemplary wireless network, which may be utilized in connection with an embodiment of the invention. Referring to FIG. 1 , there is shown an access point (AP) 102 , and a plurality of client stations (STA) 104 , 106 , and 108 , a plurality of RF channels 114 , 116 , and 118 , and a network 110 . The AP 102 may be utilized as a configurator. The STAs 104 , 106 , and 108 may be wireless terminals such as a PC, a laptop, or a PDA with integrated or plug-in 801.11 capabilities. For example, the PC may utilize a wireless NIC card and the laptop or PDA may comprise integrated 801.11 capabilities. The network 110 may be a private or public network, for example, a service provider or the Internet.
[0036] In operation, in instances where the STAs 104 , 106 , and 108 are configured, they may communicate with the AP 102 via corresponding secure RF channels 114 , 116 , and 118 , respectively. The AP 102 may communicate information received from a configured STA 104 , 106 , or 108 via the Internet 110 . In instances where the STAs 104 , 106 , or 108 are unconfigured, they may communicate with the AP 102 functioning as a configurator to request configuration information. The AP 102 functioning as a configurator may configure a requesting STA 104 , 106 , or 108 via a corresponding RF channel 114 , 116 , or 118 .
[0037] FIG. 2 is a block diagram of an exemplary system for wireless data communications comprising an extended service set (ESS) with collocation of configurators and access points (AP), in accordance with an embodiment of the invention. With reference to FIG. 2 there is shown a distribution system (DS) 210 , an extended service set (ESS) 220 , and an IEEE 802 LAN 222 . The ESS 220 may comprise a first basic service set (BSS) 202 , and may include a second BSS 212 , and may also include additional BSSs. The first BSS 202 may comprise a client station 204 , and a collocated configurator station and access point 208 . The collocated configurator station and access point 218 may comprise a configuration processor 230 . The second BSS 212 may comprise a client station 214 , and a collocated configurator station and access point 218 . The collocated configurator station and access point 218 may comprise a configuration processor 232 . The IEEE 802 LAN 222 may comprise a LAN station 224 , and a collocated configurator station and access point 226 . The collocated configurator station and access point 226 may comprise a configuration processor 234 .
[0038] The collocated configurator station and access point 208 may be adapted to function as an access point or as a configurator station. Throughout this application, for simplicity, collocated configurator station and access point 208 may be referred to as collocated device 208 . Accordingly, the collocated device 208 functioning as an access point refers to the collocated configurator station and access point 208 functioning as an access point. Additionally, the collocated device 208 functioning as a configurator refers to the collocated configurator station and access point 208 functioning as a configurator. The plurality of configuration processors, for example, configuration processor 230 , 232 and 234 may comprise suitable logic, circuitry and/or code that may be adapted to use authentication enablement information comprising data that specifies a time period during which configuration of at least one 802.11 client station, for example, client station 104 may be allowed.
[0039] A BSS 202 may comprise a plurality of proximately located stations that may communicate wirelessly, via a wireless medium. A BSS 202 that is also associated with an ESS 220 may be referred to as an infrastructure BSS. The wireless medium may comprise an RF channel. The ESS 220 , comprising a plurality of BSSs, BSS 202 and BSS 212 , for example, may be identified by a unique service set identifier (SSID). The portal 226 may also be a member in the ESS 220 . Stations 204 and 214 , associated with an ESS 220 , may communicate via a wireless medium and/or via a distribution system medium, for example the DS 210 . The DS 210 may comprise a distribution system medium that further comprises a wired medium and/or a wireless medium. A wired medium may comprise a physical communications channel that enables STA 204 to transmit information via a plurality of communications technologies, for example electrical or optical signals. In an IEEE 802.11 WLAN, the collocated configurator station and access point 208 or collocated configurator station and access point 218 may comprise the functionality of an AP and the functionality of a configurator. In an IEEE 802.11 WLAN, an AP may comprise the functionality of a station.
[0040] The collocated device 208 functioning as an AP, may enable STA 204 to transmit information via the DS 210 . Portal 226 may enable a LAN station 224 , which is located in a traditional IEEE 802 LAN, to communicate with an IEEE 802.11 STA 204 , via the DS 210 . A traditional IEEE 802 LAN may comprise a wired medium. An IEEE 802 LAN 222 may not comprise an IEEE 802.11 WLAN, for example BSS 202 . The DS 210 may utilize media access control (MAC) layer IEEE 802 addressing and/or network layer addressing. If the DS 210 utilizes MAC layer IEEE 802 addressing, the collocated device 208 , functioning as an AP, collocated configurator station and access point 218 functioning as an AP, and/or the portal 226 may comprise Ethernet switching device functionality. If the DS 210 utilizes network layer addressing, the collocated device 208 , functioning as an AP, collocated configurator station and access point 218 functioning as an AP, and/or the portal 226 may comprise router functionality.
[0041] The collocated device 208 functioning as a configurator may configure a STA 204 , thereby enabling the STA 204 to communicate wirelessly in a secure IEEE 802.11 network that utilizes encryption. The collocated device 208 functioning as a configurator, may configure a STA 204 by communicating information to the STA 204 comprising an SSID and an encryption key. The encryption key may also be referred to as a passphrase. A configured STA 204 may be authorized to utilize an IEEE 802.11 network based on the received configuration information from the collocated device 208 functioning as a configurator. A process by which the STA 204 is authenticated may comprise configuration of the STA 204 . Various embodiments of the invention comprise a method and a system for configuring the STA 204 while requiring less manual intervention from a user than is the case with some conventional methods and/or systems for configuring the STA 204 .
[0042] A non-AP station, for example, the client station 204 within the BSS 202 may subsequently form an association with the collocated device 208 functioning as an AP. The STA 204 may communicate an association request to the collocated device 208 functioning as an AP, based on the SSID that was received by the STA 204 during configuration. The collocated device 208 functioning as an AP, may communicate an association response to the STA 204 to indicate to the STA 204 the result of the association request. By associating with the collocated device 208 functioning as an AP, the station 204 may become a member of BSS 202 . Furthermore, by obtaining membership in BSS 202 , the STA 204 may become authorized to engage in secure wireless communication with other client stations in the ESS 220 . Similarly, non-AP client station 214 within a BSS 212 may form an association with the collocated configurator station and access point 218 functioning as an AP, enabling the STA 214 to become a member of BSS 212 .
[0043] Subsequent to the formation of an association between the client station 204 and the collocated device 208 functioning as an AP, the collocated device 208 functioning as an AP, may communicate accessibility information about the client station 204 to other APs associated with the ESS 220 , such as the collocated configurator station and access point 218 functioning as an AP, and portals such as the portal 226 . In turn, the collocated configurator station and access point 218 functioning as an AP, may communicate accessibility information about the client station 204 to stations in BSS 212 . The portal 226 , such as for example an Ethernet switch or other device in a LAN, may communicate reachability information about the client station 204 to stations in LAN 222 , such as LAN station 224 . The communication of reachability information about the client station 204 may enable stations that are not associated in BSS 202 , but are associated in ESS 220 , to communicate with the client station 204 .
[0044] The DS 210 may provide an infrastructure that enables a client station 204 in one BSS 202 , which has been authenticated and configured in accordance with various embodiments of the invention, to engage in a secure wireless communication with a client station 214 in another BSS 212 . The DS 210 may also enable a client station 204 in one BSS 202 to communicate with a LAN station 224 in a non-802.11 LAN 222 , such as a wired LAN. The collocated device 208 , functioning as an AP, collocated configurator station and access point 218 functioning as an AP, or portal 226 may provide a facility by which a station in a BSS 202 , BSS 212 , or LAN 222 may communicate information via the DS 210 . The client station 204 in BSS 202 may communicate information to a client station 214 in BSS 212 by transmitting the information to collocated device 208 functioning as an AP. The collocated device 208 functioning as an AP may transmit the information via the DS 210 to the collocated configurator station and access point 218 functioning as an AP, which, in turn, may transmit the information to station 214 in BSS 212 . The client station 204 may communicate information to a LAN station 224 in LAN 222 by transmitting the information to collocated device 208 functioning as an AP. The collocated device 208 functioning as an AP may transmit the information via the DS 210 to the portal 226 , which, in turn, may transmit the information to the LAN station 224 in LAN 222 .
[0045] FIG. 3 is a diagram illustrating exemplary message exchanges based on a configuration protocol and initiated at the configurator, in accordance with an embodiment of the invention. FIG. 3 presents an exemplary exchange of messages between the collocated device 208 ( FIG. 2 ) functioning as a configurator, and the client station 204 , based on a configuration protocol. In step 302 , the collocated device 208 functioning as a configurator, may be configured. A collocated device 208 functioning as a configurator, which is not configured to supply configuration information to a requesting client station 204 during authentication may be referred to as an unconfigured collocated device 208 functioning as a configurator. In an unconfigured collocated device 208 functioning as a configurator, activation of a button located thereon for a specified time duration may initiate step 302 .
[0046] The time duration for which the button is activated may correspond to, for example, a “short” button activation. In instances where the collocated device 208 functions as a configurator, configuration may comprise entering an SSID, and/or entering a passphrase. The SSID and/or passphrase that is entered and/or generated during the configuration may subsequently be utilized when configuring client stations 204 . If a passphrase is not entered, the configurator may be adapted to generate one, which may subsequently be utilized to configure client stations 204 . The entered and/or generated configuration information may be stored in non-volatile memory, and/or in a storage device at the collocated device 208 , for example. When the collocated device 208 functions as a configurator, it may retrieve the configuration information from the non-volatile memory and/or storage device and use it to configure client stations 204 .
[0047] In a configured collocated device 208 , functioning as a configurator, activation of the button thereon for a specific time duration may result in step 302 being bypassed, and step 304 initiated. The specific time duration for which the button is activated may correspond to, for example, a short button activation. In step 304 , a configurator timing window may be opened at the collocated device 208 functioning as a configurator. The opening of the configurator timing window may correspond to the start of a time duration during which a client station 204 may be configured by the collocated device 208 functioning as a configurator. The time during which the configurator timing window remains open subsequent to a short button activation may be configured at the collocated device 208 functioning as a configurator.
[0048] In step 305 , at a time instant subsequent to the opening of the configurator timing window in step 304 , the collocated device 208 functioning as an AP, may transmit IEEE 802.11 beacon frames comprising authentication enablement information, in accordance with an embodiment of the invention. The authentication enablement information may comprise data that indicates when the configurator timing window is open, and that the collocated device 208 functioning as a configurator is ready to configure a client station 204 . In one embodiment of the invention, the authentication enablement information may comprise a flag field, window_open, which may be set to a Boolean value to indicate whether the configurator timing window is open or closed. A logical value window_open=TRUE, or a numerical value window_open=1 may indicate that the configurator timing window is open, for example. A logical value window_open=FALSE, or a numerical value window_open=0 may indicate that the configurator timing window is closed, for example. The authentication enablement information may comprise a flag field, recently_cfg, which may be set to a Boolean value to indicate whether the collocated device 208 functioning as a configurator, is ready to configure a client station 204 . A logical value recently_cfg=FALSE, or a numerical value recently_cfg=0 may indicate that the collocated device 208 functioning as a configurator, is ready to configure a client station 204 , for example. A logical value recently_cfg=TRUE, or a numerical value recently_cfg=1 may indicate that the collocated device 208 functioning as a configurator, has already configured a client station 204 during the current configurator timing window open time interval and is not ready to configure a client station 204 , for example.
[0049] At a time instant when a configurator timing window is opened, a subsequent first beacon message, associated with the step 305 , transmitted by the collocated device 208 functioning as a configurator. The message, associated with the step 305 , may comprise flags window_open=TRUE, indicating that the configurator timing window is open, and recently_cfg=FALSE, indicating that the collocated device 208 functioning as a configurator, is ready to configure a client station 204 . Beacon frames transmitted by the collocated device 208 functioning as an AP, at instants in time during which the configurator timing window is not open may not comprise authentication enablement information. In step 305 , these beacon frames may be received by a client station 204 .
[0050] In a client station 204 , activation of the button, located at a client station 204 may initiate step 306 . In step 306 , a client timing window may be opened at the client station 204 . The opening of the client timing window may correspond to the start of a time duration in which a client station 204 may request to be configured by the collocated device 208 functioning as a configurator. The client station 204 may also start a discovery protocol. The discovery protocol comprises a process by which a client station 204 may locate a collocated device 208 functioning as a configurator, with which to initiate an authentication exchange. The client station 204 may scan beacon frames received from one or more collocated devices 208 functioning as either a configurator or an access point. A beacon frame collocated device 208 functioning as a configurator may comprise authentication enablement information. Subsequent to the opening of the client timing window, the client station 204 may communicate authentication response information to the collocated device 208 functioning as a configurator, via one or more messages associated with the steps 308 , 312 , 316 , 320 and 324 . The client station 204 may communicate the one or more messages, associated with the steps 308 , 312 , 316 , 320 and 324 , comprising authentication response information based on authentication enablement information contained in the transmitted beacon frame during a time interval in which the configurator timing window was open.
[0051] A button located at either the collocated device 208 functioning as a configurator, or the client station 204 , may comprise a hardware button, for example a physical button, and/or a software enabled button, for example, a glyph or icon that is displayed in a user interface.
[0052] Steps 308 , 310 , 312 , and 314 may comprise message exchanges based on IEEE 802.11 comprising an open authentication and join of a basic service set (BSS) as defined in IEEE 802.11. The BSS utilized during open authentication may utilize a different SSID than that utilized by the infrastructure BSS 202 . In step 308 , an authentication request message may be sent by the client station 204 , to the collocated device 208 functioning as a configurator. In step 310 , the collocated device 208 functioning as a configurator, may send an authentication response message to the client station 204 . In step 312 , the client station 204 may send an association request message, associated with the step 312 , to the collocated device 208 functioning as a configurator. In step 314 , the collocated device 208 functioning as a configurator, may send an association response message, associated with the step 314 , to the client station 204 .
[0053] Steps 316 , 318 , 320 , and 322 may comprise a packet exchange based on a configuration protocol, in accordance with various embodiments of the invention. The packet exchange may utilize, but may not be limited to, the Diffie-Hellman (DH) protocol. In step 316 , the client station 204 may communicate a hello packet to the collocated device 208 functioning as a configurator. The hello packet, associated with the step 316 , may indicate to the collocated device 208 functioning as a configurator, that the client station 204 is ready to be configured. In step 318 , the collocated device 208 functioning as a configurator, may communicate a key1 message to the client station 204 . The key1 message, associated with the step 318 , may comprise a configurator key. In step 320 , the client station 204 may communicate a key2 message to the collocated device 208 functioning as a configurator. The key2 message, associated with the step 320 , may comprise a client key.
[0054] In step 322 , the collocated device 208 functioning as a configurator, may communicate a configuration message to the client station 204 . The configuration message, associated with the step 322 , may comprise configuration information that may be utilized to authenticate a client station 204 . The configuration information communicated in the configuration message, associated with the step 322 , may be encrypted based on the configurator key and/or the client key. In step 324 , the client station 204 may communicate a status message to the collocated device 208 functioning as a configurator. The status message 324 may be sent subsequent to decryption of at least a portion of the configuration message 322 . The client station 204 may utilize the configurator key and/or the client key to decrypt at least a portion of the configuration message, associated with the step 322 that was previously encrypted by the collocated device 208 functioning as a configurator. The status message, associated with the step 324 , may indicate whether the client station 204 was successfully configured during the packet exchange. If the client station was successfully configured, the status message, associated with the step 324 , may indicate success. The collocated device 208 functioning as a configurator, may store authentication information about the configured client 204 in persistent memory. Persistent memory may comprise any of a plurality of device storage technologies that may be utilized to maintain information about the configured client station 204 until action is taken to release the stored information from persistent memory. These actions may comprise manual intervention at the collocated device 208 functioning as a configurator, by a user, or automatic intervention by a software process executing at the configurator.
[0055] In step 326 , the client station 204 may rejoin the WLAN based on the received configuration information. The steps performed during the rejoin, associated with the step 326 , may be substantially as defined in IEEE 802.11. The rejoin, associated with the step 326 , may occur via a secure RF channel that utilizes the received configuration information in step 322 . For example, the rejoin, associated with the step 326 , may utilize the SSID that was received by the client station during the packet exchange. Subsequent to configuration of the client station 204 , the collocated device 208 functioning as a configurator, may not be available to configure another client station 106 during the current configurator registration window time interval. Beacon frames may be transmitted by the collocated device 208 functioning as an AP, subsequent to the configuration of the client station 204 . These beacon frames may comprise information that indicates that the configurator timing window is closed, and that the collocated device 208 functioning as a configurator, has already configured a client station 204 during the current configurator timing window open time duration. This may indicate to a subsequent client station 204 that receives the beacon frames that the collocated device 208 functioning as a configurator, is not currently ready to configure a client station 204 .
[0056] In various embodiments of the invention, the packet exchange, comprising the steps 316 , 318 , 320 , 322 and 324 , may be performed by a collocated device 208 functioning as a configurator, and a client station 204 that communicate wirelessly, via a wireless medium. The collocated device 208 functioning as a configurator, and client station 204 may also communicate during the packet exchange via a wired medium, for example, via an Ethernet LAN 222 . If the collocated device 208 functioning as a configurator, receives a packet, for example an authentication request, associated with the step 308 , from the client station 204 , via a wireless medium, subsequent packet exchanges between the collocated device 208 functioning as a configurator, and client station 204 may be communicated wirelessly. If the collocated device 208 functioning as a configurator receives a packet from the client station 204 , via a wired medium, subsequent packet exchanges between the collocated device 208 functioning as a configurator, and client station 204 may be communicated via a wired medium. The received packet may be, for example, a hello packet, associated with the step 316 .
[0057] In operation, if the time duration for button activation at the collocated device 208 functioning as a configurator, corresponds to a “long” button activation, the collocated device 208 functioning as a configurator, may generate a new SSID and/or passphrase. The new SSID and/or passphrase may replace an SSID and/or passphrase that was stored in the collocated device 208 functioning as a configurator, as configuration information prior to the long button activation. For either a configured, or unconfigured collocated device 208 functioning as a configurator, a long button activation may initiate step 302 . Subsequent to a long button activation, the configurator may also release, from persistent memory, configuration information pertaining to previously configured client stations 204 . As a consequence, previously configured client stations 204 may lose the ability to engage in secure wireless communications via the BSS 202 or ESS 220 . The client stations 204 may be required to repeat the process of authentication with a collocated device 208 functioning as a configurator, to regain the ability to engage in secure wireless communications via the BSS 202 or ESS 220 .
[0058] The exchange of authentication enablement information, authentication response information and configuration information in messages associated with the steps 305 , 308 , 310 , 312 , 314 , 316 , 318 , 320 , 322 and 324 , between a collocated device 208 functioning as a configurator, and a client station 204 , may occur within a time duration in which the configurator timing window is open. The configurator timing window is closed after a time interval corresponding to a configurator timing window open duration lapses or ends. The exchange of authentication enablement information, authentication response information and configuration information, in messages associated with the steps 305 , 308 , 310 , 312 , 314 , 316 , 318 , 320 , 322 and 324 , between a collocated device 208 functioning as a configurator, and a client station 204 , may occur within a time duration in which the client timing window is open. After a time interval corresponding to a client timing window open duration lapses, the client timing window is closed.
[0059] FIG. 4 is a diagram illustrating exemplary message exchanges based on a configuration protocol and initiated at the client station, in accordance with an embodiment of the invention. FIG. 4 is substantially as described in FIG. 3 with the exception that the button activation occurs at the client station 204 , to open the client timing window, at a time instant prior to a time instant at which the button activation occurs at the collocated device 208 functioning as a configurator, to open the configurator timing window. Subsequent to the button activation to open the client timing window, associated with the step 406 , at the client station 204 , the client station 204 may wait to receive a beacon frame, associated with the step 305 . The beacon frame, associated with the step 305 , may comprise authentication enablement information from the collocated device 208 functioning as an AP, prior to proceeding with step 308 . If the client station 204 had previously received, and stored, a beacon frame comprising authentication enablement information, the client station 204 may communicate an authentication request message 308 to a collocated device 208 functioning as a configurator, that transmitted the previously received beacon frame to the client station 204 . The client station 204 may not wait to receive a beacon frame, associated with the step 305 , that was transmitted by a collocated device 208 functioning as a configurator, subsequent to the button activation, associated with the step 406 , at the client station 204 . Subsequent message exchanges in FIG. 4 are substantially as described for FIG. 3 .
[0060] FIG. 5 a is a diagram of an exemplary beacon frame format, in accordance with an embodiment of the invention. With reference to FIG. 5 a there is shown a beacon frame format 502 with a time period, Tf equal to 10 ms. The beacon frame 502 may comprise a frame control field 504 , a duration field 506 , a destination address field 508 , a source address field 510 , a BSSID field 512 , a sequence control field 514 , a beacon frame body 516 , and a frame check sequence (FCS) 518 . The format of the beacon frame may be based on specifications contained in IEEE standard 802.11.
[0061] The frame control field 504 may comprise information that identifies the frame as being a beacon frame. The duration field 506 may comprise information indicating the amount of time that is to be allocated for transmitting the beacon frame 502 and for receiving an acknowledgement of transmission. The destination address field 508 may comprise information identifying an address of one or more stations, such as, for example, client station 204 , that are intended to receive the beacon frame 502 . The source address field 510 may comprise information identifying the address of the station that transmitted the beacon frame 502 . The BSSID field 512 may comprise information identifying the address of an AP that is a current member of the basic service set (BSS), such as, for example BSS 102 . The sequence control field 514 may be utilized to identify a beacon frame that may be a segment within a larger protocol data unit (PDU). The beacon frame body 516 may comprise information that is specific to a beacon frame. The frame check sequence (FCS) field 518 may be utilized to detect errors in a received beacon frame 502 .
[0062] In operation, the beacon frame 502 may be communicated by an AP, such as, for example, AP 108 , in a BSS, such as, for example, BSS 102 . The beacon frame may enable stations within a BSS to locate an AP within the ESS. A station that is not a current member of the BSS may establish an association with the AP based on the BSSID field.
[0063] FIG. 5 b is a diagram of an exemplary beacon frame body format, in accordance with an embodiment of the invention. With reference to FIG. 5 b , there is shown a beacon frame body format 522 . The beacon frame body format 522 may comprise a timestamp field 524 , a beacon interval field 526 , a capability information field 528 , a SSID field 530 , a supported rates field 532 , a frequency hopping (FH) parameter set field 534 , a direct sequence spread spectrum parameter set field 536 , a contention free (CF) parameter set field 538 , an independent BSS (IBSS) parameter set field 540 , a traffic information message field 542 , and a setup configuration protocol (SP) information element (IE) field 544 .
[0064] The timestamp field 524 may indicate a time at which the beacon frame was transmitted. The beacon interval field 526 may indicate the amount of time that may transpire between beacon frame transmissions. The capability information field 528 may be used to communicate capabilities related to a station, such as, for example, client station 104 , that transmits the beacon frame. The SSID field 530 may identify ESS membership information of the station, such as, for example, client station 104 , transmitting the beacon. The supported rates field 532 may indicate data rates that may be supported by the station that transmitted the beacon frame. The FH parameter set field 534 may comprise information about stations that utilize frequency hopping. The DH parameter set field 536 may comprise information about stations that utilize direct sequence spread spectrum. The CF parameter set field 538 may comprise information about APs, such as, for example, AP 108 , that support contention free polling of stations in a BSS such as, for example, BSS 202 . The IBSS parameter set 540 may comprise information about stations that are members of an IBSS that do not comprise an AP and do not access stations outside of the BSS via a DS such as, for example, DS 110 . The SP IE field 544 may comprise authorization enablement information that is utilized by a configuration protocol.
[0065] In operation, a configurator, such as, for example, AP 102 functioning as a AP 102 functioning as a configurator station 102 , may transmit a beacon frame comprising the SP information element field 544 . A station within a BSS may identify a configurator based on the source address field 510 of the beacon frame, and based upon the presence of a SP information element 544 in the beacon frame body 516 . The SP information element may comprise information that is not specified in IEEE standard 802.11. Ethernet frames that comprise the SP information element may be identified based on the Ethertype field in the Ethernet frame header, where the Ethernet frame header may be as specified in IEEE 802.
[0066] FIG. 6 a is a diagram of an exemplary IEEE 802.11 information element format, in accordance with an embodiment of the invention. With reference to FIG. 6 a , there is shown an IEEE 802.11 information element (IE) 602 . The IEEE 802.11 IE 602 may comprise an identifier field (ID) 604 , a length field 606 , and an information field 608 . The ID field 604 may comprise 1 octet of binary information, for example. The length field 606 may comprise 1 octet of binary information, for example. The information field 608 may comprise a plurality of octets of a number specified in the length field 606 .
[0067] FIG. 6 b is a diagram of an exemplary configuration protocol information element, in accordance with an embodiment of the invention. With reference to FIG. 6 b , there is shown a setup configuration protocol (SP) IE 612 . The SP IE 612 may comprise an ID field 614 , a length field 616 , an organizational unique identifier (OUI) field 618 , a configuration protocol type field 620 , a configuration protocol subtype field 622 , a version field 624 and a data field 626 . The format of the SP IE 612 may be based on the IEEE 802.11 IE 602 . The ID field 614 may comprise 8 bits of binary information, for example, and may comprise a value suitable for uniquely identifying the information element as being utilized for setup. The length field 616 may comprise 8 bits of binary information, for example. The OUI field 618 may comprise 24 bits of binary information, for example, and may comprise a value suitable for unique identification.
[0068] When the configuration protocol window is opened by the configurator, for example, the AP 102 functioning as a configurator, the AP 102 may indicate this event to the other stations connected to the ESS, for example, ESS 220 by broadcasting this information in beacon frames 305 and probe response information elements. Alternatively, the ID field 614 may comprise a value suitable for identifying the information element as a category of information elements that may be used by multiple protocols, and the OUI field 618 may comprise a value suitable for identifying the information element as being utilized for setup. The configuration type field 620 may comprise 8 bits of binary information, for example, and may be vendor specific. The configuration subtype field 622 may comprise 8 bits of binary information, for example, and may be vendor specific. The version field 624 may comprise 8 bits of binary information, for example, and may comprise a value suitable for distinguishing different versions of the SP IE 612 . The data field 626 may comprise 8 bits of binary information, for example, to provide authorization enablement information that may be utilized by a client station that is being configured and authenticated utilizing a configuration protocol.
[0069] FIG. 6 c is a diagram of an exemplary configuration protocol data field format, in accordance with an embodiment of the invention. With reference to FIG. 6 c there is shown a configuration protocol data field 632 . The configuration protocol data field 632 may comprise a configuration protocol window open field 634 , a configuration protocol for wireless distribution system (WDS) window open field 636 and a reserved field 638 reserved for future use. The configuration protocol window open field 634 may comprise 1 bit of binary information, for example, and may comprise information suitable for specifying a configurator timing window to a client station, such as, for example, client station 104 . The configuration protocol window open field 634 may be set to 1, for example, if the configuration protocol window is currently open for a configuration protocol client, for example, client station 104 and may be set to 0, for example, otherwise. The configuration protocol window open field 634 may indicate whether the configurator timing window is open, or closed. In this regard, the configuration protocol open window field 634 may specify a time period during which configuration is allowed. The configuration protocol for wireless distribution system (WDS) window open field 636 may be set to 1, for example, if the configuration protocol window is currently open for a configuration protocol WDS client and may be set to 0, for example, otherwise. The reserved field may comprise 6 bits of binary information, for example, and may be utilized for future use. The configurator, for example, AP 102 functioning as a configurator may indicate a recently configured state if none of the bits in the SP IE field 612 are set to 1, for example. The recently configured state may indicate whether the configurator has already configured another client during the current configuration protocol window opening period.
[0070] In operation, when the configurator timing window is open, a client, such as, for example, client station 104 , may be permitted to utilize a configurator, such as, for example, AP 102 functioning as a configurator station 102 , for configuration and authentication based on a configuration protocol. If the configurator timing window is closed, a client may not be permitted to utilize the configurator for configuration and authentication based on a configuration protocol. The amount of time that may transpire between when a configurator timing window is open and when the configurator timing window is subsequently closed may be determined during configuration of the configurator. If the client expected to be configured during the current configurator timing window but was unable to do so as a result of information in the recently configured field, the client may report that an unintended client may have utilized the configurator for configuration and authentication based on a configuration protocol.
[0071] FIG. 7 a is a diagram of an exemplary configuration protocol packet header format, in accordance with an embodiment of the invention. With reference to FIG. 7 a , there is shown configuration protocol packet header format 702 . The configuration protocol packet header 702 may comprise an Ethernet header field 724 , an extensible authentication protocol (EAP) header field 726 , a version field 728 , a configuration protocol type field 730 , a flags field 732 and a reserved field 734 for future use. The Ethernet header field 724 may comprise an Ethernet destination address and an Ethernet source address, for example. The EAP header field 726 may comprise data that specifies the version, type and length of the EAP header. The version field 728 may comprise information that identifies the version of the configuration protocol packet header 702 . The configuration protocol type field 730 may comprise information that identifies the packet type of the configuration protocol. The configuration protocol type field 730 may indicate a type of transmitted message between the configurator 208 and the client station 204 . For example, a hello message as illustrated in step 316 , a public key 1 message as illustrated in step 318 , a public key 2 message as illustrated in step 320 , a SSID/passphrase message as illustrated in step 322 or a status message 324 . The flags field 732 may comprise 8 bits of binary information, for example, and may be adapted to provide additional information pertaining to a configuration protocol at the configurator.
[0072] FIG. 7 b is a diagram of an exemplary EAP header message format for a configuration protocol, in accordance with an embodiment of the invention. With reference to FIG. 7 b , there is shown an EAP header 726 . The EAP header 726 may comprise a version field 754 , a packet type field 756 , a packet length field 758 and an EAP body field 760 . The version field 754 may comprise 8 bits of binary information, for example, that indicates the version of the extensible authentication protocol over LAN (EAPOL). The packet type field 756 may comprise 8 bits of binary information, for example, that indicates the type of the EAPOL packet utilized. The packet length field 758 may comprise 16 bits of binary information, for example, that indicates the length of the configuration protocol packet header 702 . The EAP header body field 760 may comprise data that indicates the EAP version, EAP type and EAP length of the configuration protocol packet header 702 .
[0073] FIG. 7 c is a diagram of an exemplary EAP header body format for a configuration protocol, in accordance with an embodiment of the invention. With reference to FIG. 7 c , there is shown an EAP header body field 760 . The EAP header body field 760 comprises an EAP code field 732 , an EAP ID field 734 , an EAP length field 736 , an EAP type field 737 , EAP vendor ID field 738 and an EAP vendor type field 739 . The EAP code field 732 may comprise information that indicates whether the EAP packet is a request identity packet or a response identity packet. For example, an access point 102 may communicate a request-identity EAP packet to the client station 104 to identify the client station trying to access the AP 102 . The client station 104 may respond by communicating a response-identity EAP packet to the AP 102 confirming its identity. The EAP ID field 734 may comprise information that indicates the current identity of the request-identity EAP packet. The EAP length field 736 may comprise information that indicates the length of the EAP header field 726 . The EAP type field 737 may comprise information that indicates the type of EAP packet. The EAP vendor ID field 738 may comprise 24 bits of binary information, for example, that indicates the vendor ID of the EAP packet. The EAP vendor type field 739 may comprise 32 bits of information, for example, that indicates the vendor type of the EAP packet.
[0074] FIG. 7 d is a diagram illustrating an exemplary configuration protocol packet type key format, in accordance with an embodiment of the invention. With reference to FIG. 7 d , there is shown a configuration protocol packet type key format 740 . The configuration protocol packet type key 740 comprises a configuration protocol header 702 , a public key length 744 and a public key 746 . The configuration protocol packet type key 1 and the configuration protocol packet type key 2 may have a format similar to the configuration protocol packet type key format 740 . The configuration protocol header 702 is substantially as described in FIG. 7 a . The public key length field 744 may comprise information that indicates the length of the public key utilized. The public key field 746 may comprise algorithm information that specifies the public key 1 for the configuration protocol packet type key 1 or public key 2 for the configuration protocol packet type key 2. For example, an encryption type may be specified during setup configuration and authorization of the client such as, for example, the Diffie-Hellman (DH) algorithm. The public key field 746 for the public key 1 message may comprise the configurator's generated public key for algorithm information exchange, for example, DH algorithm information exchange. The public key field 746 for the public key 2 message may comprise the client's generated public key for algorithm information exchange, for example, DH algorithm information exchange. The client, for example, client station 104 may transmit a public key 2 message as illustrated in step 324 in response to a transmitted public key 1 message as illustrated in step 322 previously received from a configurator. The public key 2 message may be transmitted as plaintext.
[0075] FIG. 7 e is a diagram illustrating an exemplary configuration protocol packet type info format, in accordance with an embodiment of the invention. With reference to FIG. 7 d , there is shown configuration protocol packet type info format 750 . The configuration protocol packet type info format 780 comprises a configuration protocol header 702 , a service set identifier (SSID) field 784 , an encrypted passphrase field 786 and a passphrase length field 788 .
[0076] The SSID field 784 may comprise a unique identifier attached to the header of the configuration protocol packets sent over a WLAN that may act as a password when a client station, for example, client station 104 tries to connect to the BSS, for example, BSS 202 . The SSID field 784 may comprise information that indicates the SSID of the secure configuration protocol network. The SSID field 784 may specify an ESS, such as, for example, ESS 220 , to which the client may become a member. The encrypted passphrase field 786 may comprise information that is utilized to configure the client based on a configuration protocol. The encrypted pas sphrase field 786 may be randomly generated at the AP 102 and transmitted to the client 104 in an encrypted format. The key for the encryption may be derived using the Diffie-Hellman (DH) protocol or its variant, for example. The DH protocol may generate a shared 1536-bit key, for example. This key may be converted to a 128-bit key using an encryption algorithm such as secure has access 1 (SHA1), for example. The 128-bit key may be utilized for advanced encryption standard (AES) wrapping of the encrypted passphrase before being transmitted over the air. The encrypted passphrase field 786 may specify, as ciphertext, a secret key that may be utilized by the client to establish secure communications in an IEEE 802.11 WLAN. The encrypted passphrase field 786 may be decrypted based on the exchange of shared keys in the public key 1 message and the public key 2 message. The passphrase length field 788 may comprise information that indicates the length of the encrypted passphrase.
[0077] A configuration protocol packet type hello may be communicated from the client to the configurator to inform the configurator that the client is ready for exchange of packets. The configuration protocol packet type key 1 may be communicated by the configurator to the client in response to receiving the configuration protocol packet type hello from the client. The configuration protocol packet type key 2 may be communicated by the client to the configurator in response to receiving the configuration protocol packet type key 1 from the configurator. After the configuration protocol packet type key 1 and configuration protocol packet type key 2 have been exchanged, the configurator and client may calculate a shared secret key that may be utilized to encrypt the configuration information. The configuration protocol packet type info may be communicated by the configurator to the client in response to receiving the configuration protocol packet type key 2 from the client. The configuration protocol packet type status may be communicated by the client to the configurator in response to receiving the configuration protocol packet type info from the configurator. The configuration protocol packet type status may indicate the status of exchange of the configuration protocol messages. If the client successfully receives and decrypts the configuration information in the configuration protocol packet type info message, the client may communicate a configuration protocol packet type status message indicating a success of exchange of messages.
[0078] If the client did not receive the configuration protocol packet type info or is unable to decrypt the configuration information in the configuration protocol packet type info message, the client may communicate a configuration protocol packet type status message indicating a failure of exchange of messages. The configuration protocol packet type status may be communicated by the configurator 208 or the client station 204 at anytime to terminate the exchange of messages between the configurator 208 and the client station 204 , if required. A configuration protocol packet type echo request may be communicated by the client to the configurator during link verification and wired discovery. A configuration protocol packet type echo response may be communicated by the configurator to the client during link verification and wired discovery in response to a received configuration protocol packet type echo request from the client. The configuration protocol exchange is substantially as described in FIG. 3 .
[0079] Certain aspects of a method and system for enabling exchange of information in a secure communication system may comprise at least one configuration processor, for example, configuration processor 230 that uses authentication enablement information comprising data that specifies a time period during which configuration of at least one 802.11 client station, for example, client station 204 is allowed. The data that specifies a time period during which configuration is allowed may comprise a configuration protocol window open field 634 , which indicates a period when a configuration setup window is open. At least one client station, for example, client station 204 may be configured via the authentication enablement information comprising recently configured data, which indicates whether at least one configurator has configured at least one other client station within the time period during which the configuration is allowed.
[0080] The authentication enablement information may comprise recently configured data for configuring the client station 204 , which indicates whether the configurator 208 has configured at least one other client station, for example, client station 206 during the configuration setup window opening period. The configuration of the client station 204 may be disallowed if the recently configured data indicates configuration of at least one other client station, for example, client station 206 by the configurator 208 within the time period during which the configuration is allowed. The authentication enablement information may comprise at least one version field, for example, version field 624 , which indicates a version of a configuration protocol that is utilized to configure the client station 204 .
[0081] The configuration protocol version field 624 may comprise 6 bits of binary information, for example, and may comprise information suitable for distinguishing different versions of a configuration protocol. The configuration protocol window open field 634 may comprise 1 bit of binary information, for example, and may comprise information suitable for specifying a configurator timing window to a client station, such as, for example, client station 104 . The configuration protocol window open field 634 may indicate whether the configurator timing window is open, or closed. The authentication enablement information may further comprise an encrypted passphrase, for example, the encrypted passphrase field 786 , which authenticates the 802.11 client station 204 . The encrypted passphrase field 786 may be generated by an encryption algorithm, for example, the Diffie-Hellman (DH) algorithm. The public key field 746 for the public key 1 message may comprise the configurator's generated public key for algorithm information exchange, for example, DH algorithm information exchange. The public key field 746 for the public key 2 message may comprise the client's generated public key for algorithm information exchange, for example, DH algorithm information exchange. The client, for example, client station 104 may transmit a public key 2 message as illustrated in step 324 in response to a transmitted public key 1 message as illustrated in step 322 previously received from a configurator. The public key 2 message may be transmitted as plaintext.
[0082] The authentication enablement information may further comprise at least one service identifier, for example the SSID field 784 , which identifies the 802.11 client station 204 . The configuration processor 230 may be adapted to authenticate the 802.11 client station 204 via the authentication enablement information by exchanging a plurality of public keys. The authentication enablement information may further comprise status data, which indicates a status of messages exchanged between at least one configurator, for example, configurator 208 and at least one 802.11 client station, for example, client station 204 .
[0083] Accordingly, the present invention may be realized in hardware, software, or a combination of hardware and software. The present invention may be realized in a centralized fashion in at least one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software may be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.
[0084] The present invention may also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.
[0085] While the present invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims. | A collocated device functioning as a configurator can use short and long button activations to enter a configuration state, open a timing window, and force client devices currently joined to a network to rejoin the network. If the collocated device functioning as a configurator is unconfigured, a short (or long) button activation can initiate a configuration sequence. A short button activation on that same collocated device, once configured, can cause the device to open a configurator timing window, during which one or more devices can be provided the information necessary to securely communicate on a network. A long (or short) button activation can be used to force all currently connected client devices, or rejoin the network using a new Service Set Identifier (SSID) or passphrase. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Phase Entry of International Application No. PCT/IB2008/002653, filed on Oct. 3, 2008, which claims priority to European Application EP 07291214.0, filed on Oct. 5, 2007, both of which are incorporated by reference herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to the use of recombinant LAG-3 or derivatives thereof in order to boost a monocyte-mediated immune response. It enables an increase in monocyte numbers in blood. It finds many applications in particular in the development of novel therapeutic agents in cancer immunotherapy.
[0004] 2. State of the Art
[0005] In the description which follows, the references between brackets [ ] refer to the attached reference list. The lymphocyte activation gene 3 (hlag-3) expressed in human CD4 + and CD8 + activated T cells as well as in activated NK cells encodes a 503 amino acids type I membrane protein (LAG-3) with four extracellular immunoglobulin superfamily (IgSF) domains [1]. A murine lymphocyte activation gene 3 (mlag-3) was cloned and approximatively 70% of homology was found with hlag-3, with the same proline rich motif in the intracytoplasmic tail.
[0006] LAG-3 (CD223), described as being a natural high affinity ligand for MHC class II, is known to induce maturation of monocyte-derived dendritic cells in vitro, and is used as an immunotherapy adjuvant to induce CD4 T helper type 1 responses and CD8 T cell responses in vivo [2]. Further information regarding LAG-3 and its use as an immunostimulant may be found in TRIEBEL et al. [1], TRIEBEL et al. [3], and HUARD et al. [4]. Some forms of soluble LAG-3 can bind to MHC class II molecules and can induce dendritic cells to mature and migrate to secondary lymphoid organs where they can prime naïve CD4-helper and CD8-cytotoxic T cells leading to tumour rejection [5]. More recently a recombinant soluble human LAG-3lg fusion protein (IMP321) was shown to activate a large range of effector cells in both innate and acquired immune responses, for example inducing monocytes-macrophages to secrete cytokines/chemokines [6].
[0007] Monocytes are produced by the bone marrow from haematopoietic stem cell precursors called monoblasts. They constitute between three to eight percent of the leukocytes in the blood. Monocytes circulate in the bloodstream for about 24 hours (half-life of 8 hours) and then typically move into tissues throughout the body. In the tissues, monocytes mature into macrophages, epithelioid cells or antigen-presenting cells (APCs, for example dendritic cells). Monocytes are responsible for phagocytosis (ingestion) of foreign substances in the body. Monocytes can perform phagocytosis using intermediary (opsonising) proteins such as antibodies or complement that coat the pathogen, as well as by binding to the pathogen directly via pattern-recognition receptors that recognize pathogens. Monocytes are also capable of killing infected host cells via antibody, termed antibody-dependent cell-mediated cytotoxicity (ADCC). Due to their secretion and phagocytosis properties, monocytes-macrophages occur in aspecific and specific immune response.
[0008] The study of membrane markers allows the identification of monocyte populations, mature or not, dystrophic or not. The molecules present on monocyte membranes, mature or not, are almost always non specific but correspond to the following activities:
receptor for the Fc fragment of IgG (CD16, CD32, CD64), receptor for the Fc fragment of IgE (CD23), receptor for complement fractions (CD11b, CD21/CD35), leukocyte adhesion proteins (CD11a, CD11c), protein facilitating binding to LPS of Gram—bacteria (CD14), protein with tyrosine phosphatase activity (CD45).
SUMMARY
[0015] The authors of the present invention have now discovered, entirely unexpectedly, that human LAG-3 or derivatives thereof when inoculated into patients with highly malignant tumors, for example patients with metastatic breast cancer (MBC) or metastatic renal clear-cell carcinoma (MRCC), induced a potent immunity which is monocyte dependent. Said induced immunity manifests itself by a significant increase in blood monocyte counts.
[0016] This result was achieved by means of plural administration of LAG-3 or derivatives thereof to patients receiving immunotherapy or chemo-immunotherapy. This result is rather surprising since binding to, and activation of, monocytes is not expected to be followed by monocyte expansion. Indeed monocytes are end-of-differenciation hematopoietic cells and can not proliferate. They can stay in the blood as monocytes or differentiate toward either macrophages or dendritic cells under the influence of different cytokines, until they die. Thus it is believed, without limitation to the following theory, that the mechanism of action involved may be a proliferative signal directed to hematopoietic precursor cells (before the promonocyte stage) residing in the bone marrow, or an increase in the half-life or residence time of mature circulating monocytes.
[0017] Therefore the present invention relates to the use of a recombinant LAG-3 protein or derivative thereof that elicits monocyte mediated immune response, for the manufacture of a medicament inducing an increase in monocyte numbers for the treatment of an infectious disease or cancer. By “derivatives of LAG-3”, in the sense of the present invention, is meant mutants, variants and fragments of LAG-3 provided that they maintain the ability of LAG-3 to bind MHC class II molecules.
[0018] Thus, the following forms of LAG-3 may be used:
the whole LAG-3 protein, a soluble polypeptide fragment thereof consisting of at least one of the four immunoglobulin extracellular domains, namely the soluble part of LAG-3 comprised of the extracellular region stretching from the amino acid 23 to the amino acid 448 o the LAG-3 sequence disclosed in French patent Application FR 90 00 126, a fragment of LAG-3 consisting of substantially all of the first and second domains, a fragment of LAG-3 consisting of substantially all of the first and second domains or all of the four domains, such as defined in WO 95/30750, a mutant form of soluble LAG-3 or a fragment thereof comprising the D1 and D2 extracellular domains and consisting of:
a substitution of an amino acid at one of the following positions: position 73 where ARG is substituted with GLU, position 75 where ARG is substituted with ALA or GLU, position 76 where ARG is substituted with GLU, or a combination of two or more of those substitutions, a substitution of an amino acid at one of the following positions: position 30 where ASP is substituted with ALA, position 56 where HIS is substituted with ALA, position 77 where TYR is substituted with PHE, position 88 where ARG is substituted with ALA, position 103 where ARG is substituted with ALA, position 109 where ASP is substituted with GLU, position 115 where ARG is substituted with ALA, or a deletion of the region comprised between the position 54 and the position 66, or a combination of two or more of those substitutions.
[0039] Those mutants are described by HUARD et al. (Proc. Natl. Acad. Sci. USA, 11 : 5744-5749, 1997).
a physiological variant of LAG-3 comprised of the soluble 52 kDa protein containing D1, D2 and D3. a recombinant soluble human LAG-3lg fusion protein (IMP321), a 200-kDa dimer produced in Chinese hamster ovary cells transfected with a plasmid encoding for the extracellular domain of hLAG-3 fused to the human IgG1 Fc.
[0042] By “medicament”, in the sense of the present invention, is meant an effective plurality of doses of a recombinant LAG-3 protein or derivative thereof. By “effective plurality of doses of a recombinant LAG-3 protein or derivative thereof”, in the sense of the present invention, is meant a formulation that allows administration of one dose of a recombinant LAG-3 protein or derivative thereof every one to several weeks for at least 12 weeks, and preferably for at least 24 weeks, separated by 13-day±2 days administration-free intervals. Advantageously, the administration is an every-two-week schedule. By “one dose of a recombinant LAG-3 protein or derivative thereof”, in the sense of the present invention, is meant a formulation that allows one administration in the range of 0.25-30 mg, preferably 1-6.25 mg, more preferably 6-30 mg, and for example about 1.25 mg of recombinant LAG-3 protein or derivative thereof to a patient in need thereof having a body mass index (weight/height 2 ) in the range of 18-30 kg/m 2 .
[0043] The recombinant LAG-3 or derivatives thereof are administered in a free form, for example in a soluble form by inoculating them systemically, for example as a subcutaneous, intramuscular or intravenous injection, preferably as a subcutaneous injection. Said recombinant LAG-3 or derivatives thereof may also be formulated so as to allow administration with a compound having anti-cancer or anti-infectious disease immunotherapeutical or chemotherapeutical properties. By “administration with a compound”, in the sense of the present invention, is meant an administration of a recombinant LAG-3 or derivative thereof before, with, or subsequent to, the administration of said compound. By “compound having anti-cancer or anti-infectious disease chemotherapeutical properties”, in the sense of the present invention, is meant for example a chemotherapy agent selected from the group consisting of taxanes (paclitaxel, docetaxel), gemcitabine and anthracyclines (doxorubicine) or an anti-viral agent such as ribavirin.
[0044] In a particular embodiment of the invention, recombinant LAG-3 protein or derivative thereof is administered to patients after the first administration of the cytotoxic compound having anti-cancer or anti-infectious disease chemotherapeutical properties. Advantageously, recombinant LAG-3 protein or derivative thereof is administered to patients is administered 12 to 96 hours after the administration of the cytotoxic compound having anti-cancer or anti-infectious disease chemotherapeutical properties. In another embodiment, recombinant LAG-3 protein or derivative thereof is administered to patients is administered one or two days after the first administration of the compound having anti-cancer or anti-infectious disease chemotherapeutical properties. In another particular embodiment of the invention, recombinant LAG-3 protein or derivative and the cytotoxic compound having anti-cancer or anti-infectious disease chemotherapeutical properties are administered simultaneously, separately or sequentially.
[0045] Advantageously, in this particular embodiment of the invention, recombinant LAG-3 protein or derivative thereof is administered at least six times, for example seven times, ten times, twelve times or more. Advantageously, in this particular embodiment of the invention, recombinant LAG-3 protein or derivative thereof is administered on an every-two-week schedule. Advantageously, recombinant LAG-3 protein or derivative thereof is administered at a dose comprised between 0.25 to 30 mg, eventually at a dose comprised between 6 to 30 mg, eventually at a dose comprised between 8 to 25 mg, eventually between 12 and 20 mg. By “compound having anti-cancer or anti-infectious disease immunotherapeutical properties”, in the sense of the present invention, is also meant for example a compound selected from the group consisting of therapeutic antibodies killing tumour cells through ADCC (antibody-dependent cell cytotoxicity), and mixtures thereof, and preferably from the group consisting of rituximab, cetuximab, edrecolomab, and trastuzumab.
[0046] In a particular embodiment of the invention, recombinant LAG-3 protein or derivative thereof and therapeutic antibodies are administered to patients simultaneously, separately or sequentially. Advantageously, in a particular embodiment of the invention, recombinant LAG-3 protein or derivative thereof is administered to patients the same day as therapeutic antibodies.
[0047] The present invention also relates to kit-of-parts, i.e. a combined preparation, containing recombinant LAG-3 protein or derivative thereof and a therapeutic antibody for simultaneous, separate or sequential use. Advantageously, the kit-of-parts contains recombinant LAG-3 protein or derivative thereof and a therapeutic antibody selected from the group consisting of rituximab, cetuximab, edrecolomab, and trastuzumab. Preferentially, the kit-of-part of the invention contain recombinant LAG-3 protein or derivative thereof and rituximab.
[0048] In the kit-of-parts of the invention, recombinant LAG-3 protein or derivative thereof and a therapeutic antibody form a functional unity, because of a synergistic cytotoxic effect between the two components. This effect is a new joint effect, because the two components administered alone does not have the same effect as when administered as a combined preparation. The present invention also relates to kit-of-parts, i.e. a combined preparation, containing recombinant LAG-3 protein or derivative thereof and a compound having anti-cancer or anti-infectious disease chemotherapeutical properties for simultaneous, separate or sequential use. Advantageously, the kit-of-parts contains recombinant LAG-3 protein or derivative thereof and a compound having anti-cancer or anti-infectious disease chemotherapeutical properties selected from the group consisting of taxanes (paclitaxel, docetaxel), gemcitabine and anthracyclines (doxorubicine).
[0049] The present invention also relates to a method for treating a pathological condition involving a monocyte mediated immune response, comprising administering the medicament as above defined to a patient in need thereof. By “pathological condition involving a monocyte mediated immune response”, in the sense of the present invention, is meant viral infectious diseases, parasitic infectious diseases, bacterial infectious diseases, and cancer. Other advantages may also appear to one skilled in the art from the non-limitative examples given below, and illustrated by the enclosed figures.
BRIEF DESCRIPTION OF THE FIGURES
[0050] FIG. 1 represents fluorescence-activated cell sorting (FACS) analysis of monocytes (i.e. CD14 + CD45 + cells) in PBMCs from metastatic breast carcinoma patients.
[0051] FIG. 2 represents fluorescence-activated cell sorting (FACS) analysis of monocytes (i.e. CD14 + CD45 + cells) in fresh whole blood from metastatic breast carcinoma patients.
[0052] FIG. 3 represents fluorescence-activated cell sorting (FACS) analysis of monocytes (i.e. CD14 + CD45 + cells) in fresh whole blood from metastatic renal cell cancer patients.
[0053] FIG. 4 represents fluorescence-activated cell sorting (FAGS) analysis of monocytes (i.e. CD14 + CD45 + cells) in fresh whole blood from metastatic breast carcinoma patients.
[0054] FIG. 5 represents the pharmacokinetic profiles of IMP321 measured by ELISA in the plasma of metastatic renal cell cancer patients.
[0055] FIG. 6 represents the flow cytometry analysis of PBMC cultured in different conditions with rituximab and/or IMP321.
DETAILED DESCRIPTION
Example 1
Monocytes Increase in Metastatic Breast Cancer (MBC) Patients Using Low IMP321 Dose
[0056] Five MBC patients, receiving chemotherapy known to induce tumour cell apoptosis, each received one subcutaneous IMP321 dose of 0.25 mg 1-2 days after chemotherapy every other week, for 24 weeks, separated by 14-day administration-free intervals. Blood samples were collected in heparinated lithium tubes (Vacutainer; BD Biosciences) from each patient, 14 days after the last IMP321 injection (i.e. looking at lasting immunomodulatory effects of the product), at 3 months (Day 85) and 6 months (Day 170). PBMCs were isolated on Ficoll-Paque gradient (Pharmacia) using LeucoSep tubes (Greiner Bio-One), and used immediately. The increase in number of monocytes was analysed by fluorescence-activated cell sorting (FACS) in said fresh PBMC samples (because monocytes are sensitive to freezing), and compared with the monocyte counts carried out on fresh PBMC samples collected before IMP321 administration (Day 1).
[0057] The results are represented in FIG. 1 . The results showed a 2.5-fold (at 3 months, Day 85) and a 3.5-fold (at 6 months, Day 170) mean increase of monocyte counts at this low IMP321 dose clinical protocol. In order to confirm the above results, a more direct and probably more accurate approach was carried out, which was to quantify directly ex-vivo the number of monocytes in whole blood (i.e. without prior purification of PBMCs on Ficoll gradient) by first measuring the exact volume of blood to be analyzed with diluted fluorescent beads and then counting the number of CD14 + cells (i.e. monocytes) in the gated CD45 + (leukocytes) cells present in this whole blood volume.
[0058] The results are represented in FIG. 2 . The results showed a 4.4-fold mean increase at Day 170 (2.8-fold at Day 85) when IMP321 was given at low dose (0.25 mg) for a long period of time, 6 months, with 12 injections, showing strong and direct stimulation of the targeted MHC class II + monocyte-like hematopoietic cells.
Example 2
Monocytes Increase in Metastatic Renal Clear-cell Carcinoma (MRCC) Patients Using High IMP321 Dose
[0059] Three MRCC patients each received one subcutaneous IMP321 dose of 6.25 mg every other week, for 12 weeks, separated by 14-day administration-free intervals. Blood samples were collected as described above from each patient, 14 days after the last IMP321 injection (i.e. looking at lasting immunomodulatory effects of the product), at 2 months (Day 57) and 3 months (Day 85), and used immediately. The expansion of CD14 + CD45 + cells was analysed by FACS in fresh blood samples (because monocytes are sensitive to freezing), and compared with the monocyte counts carried out on fresh blood samples collected before IMP321 administration (Day 1).
[0060] The results are represented in FIG. 3 . The results showed a 2-fold (at 3 months, Day 85) mean increase of monocyte counts with this high IMP321 dose clinical protocol where patients received only 6 injections.
Example 3
Monocytes Increase in Metastatic Breast Carcinoma Patients Receiving Paclitaxel and IMP321 Doses
[0061] Patients receiving as a first line chemotherapy for metastatic breast carcinoma 6 cycles of paclitaxel (80 mg/m 2 given i.v.) on days 1, 8, and 15 of a 28 day cycle, received 1-30 mg s.c. (sub-cutaneous) IMP321 on days 2 and 16 of each 28-day cycle. Alternatively, IMP321 was administered at days 3 or 17. Accordingly, each patient received a standard 6-month course of weekly paclitaxel with 12 s.c. injections of IMP321, each injection being given one to two days after paclitaxel administration on an every-two-week schedule. The increase in absolute monocyte counts per microliter of fresh blood was analysed by fluorescence-activated cell sorting (FACS), 14 days after the last injection, at 3 months (Day 85) and 6 months (Day 170) compared to day 1.
[0062] The results obtained in patients injected with a low dose IMP321 (1.25 mg) are represented in FIG. 4 . These data showed that doses of 1.25 mg in most if not all patients ( FIG. 4 ) induce an expansion of the monocyte subset pool in the blood. It is predicted that the optimal dose regimen for IMP321 will be between 6 and 30 mg/injection. These doses have been shown to be safe and give an acceptable systemic exposure based on the results of pharmacokinetics data obtained in metastatic renal cell cancer patients ( FIG. 5 ). A blood concentration of IMP321 superior to 1 ng/ml for at least 24 hours after s.c. injection could be obtained in patients injected by IMP321 doses of more than 6 mg ( FIG. 5 ).
Example 4
Treatment of Advanced Pancreas Cancer Patients Receiving Gemcitabine and IMP321 Doses
[0063] Patients, receiving as a first line chemotherapy for advanced pancreas cancer (or patients not eligible for surgical removal of the tumor) 6 cycles of standard gemcitabine (1 gm/m 2 given i.v. over 30 min) on days 1, 8, and 15 of a 28 day cycle, receive in addition 6 to 30 mg s.c. IMP321 on days 2 and 16 of each 28-day cycle. Alternatively, IMP321 is administered at days 3 or 17. Accordingly, each patient receives a standard 6-month course of gemcitabine with 12 s.c. injections of IMP321, each injection being given one to two days after gemcitabine administration on an every-two-week schedule. The number of monocytes is analysed by fluorescence-activated cell sorting (FACS) as in example 1.
Example 5
Induction of Increased Rituximab-mediated ADCC by Low Doses IMP321
[0064] PBMCs are first incubated for 40 hours with IL-2 (100 U/ml), with or without IMP321 (at the concentrations 0 μg/m, 0.03 μg/ml or 0.1 μg/ml). PBMCs are then incubated with increasing concentrations of rituximab (0, 0.5 and 5 μg/ml) in the presence of target cells (i.e. human CD20 + Raji B cells). Raji cells were first labeled with CFSE (carboxy-fluorescein succinimidyl ester), incubated in medium with rituximab at 0, 0.5 or 5 μg/ml and cocultured with effector cells at an effector-target ratio of 25:1 for 6 hours at 37° C. The cells were then incubated with 7-AAD (7-amino-actinomycin-D) for 15 min on ice and analyzed by flow cytometry to determine the percentage of dead CFSE + 7-AAD + Raji target cells (i.e. % of cytotoxicity).
[0065] The results are presented in FIG. 6 . Increasing the concentration of rituximab increased the percentage of cytotoxicity, clearly showing a dose-dependent ADCC activity. When 0.03 or 0.1 μg/ml IMP321 is added, the percentage of cytotoxicity greatly increased. For instance, a 30% cytotoxicity is observed with 0.5 μg/ml rituximab in the presence of 0.1 μg/ml IMP321 which is superior to the 25% cytotoxicity value obtained with 5 μg/ml rituximab in the absence of IMP321. Thus, adding 0.1 μg/ml IMP321 potentializes 10-15 fold the activity of rituximab because a superior cytotoxicity is obtained with 10 time less antibody when a low dose IMP321 (0.1 μg/ml) is added. These data show the synergistic effect between rituximab and IMP321.
REFERENCE LIST
[0000]
[1] TRIEBEL et al., J. Exp. Med., 171 : 1393-1405, 1990;
[2] BRIGNONE et al., J. Immune Based Ther Immunotherapies, 5: 5, 2007;
[3] TRIEBEL et al., Trends Immunol., 24 : 619-622, 2003;
[4] HUARD et al., Proc. Natl. Acad. Sci. USA, 94 : 5744-5749, 1997;
[5] PRIGENT et al., Eur. J. Immunol., 29 : 3867-3876, 1999; and
[6] BRIGNONE et al., J. Immunol., 179: 4202-4211, 2007. | The present disclosure relates to the use of a recombinant LAG-3 or derivatives thereof in order to boost a monocyte-mediated immune response, in particular to elicit an increase in the number of monocytes in blood. This finds use in the development of novel therapeutic agents for the treatment of an infectious disease or cancer. | 0 |
INFORMATION DISCLOSURE STATEMENT
It is well known in the art to recycle paper fibers by mechanically and chemically processing the paper into a slurry, and treating the slurry to remove ink, clay and other unwanted additives and contaminants. Conventional techniques including mechanical and chemical treatment, centrifuging, flotation, screening and the like will remove the greatest part of the unwanted material from the fibers, but the prior art techniques tend to leave a certain amount of ink and other contaminants on the fibers. As a result, the contaminants are present when the fibers are reused to make paper.
One technique utilized as a final step for removal of fine particles is to wash the fibers by allowing the fibers to collect on a screen, and flowing wash water over the fibers and through the screen. The concept is that the wash water will pick up the contaminants and carry the contaminants away from the fibers. The problem with the technique is that the fibers collect on the screen, and the mass of fibers tends to retain some of the contaminants so that the washing is not entirely effective. A similar technique is disclosed in the Gartland U.S. Pat. No. 4,215,447. The Gartland device includes a screen on which the fibers tends to collect, and wash water is flowed through the fibers and through the screen. The Gartland improvement is in the provision of stirring means which removes clusters of fibers from the screen and causes the clusters to be entrained in a fluid stream moving from an inlet for the pulp to an outlet for the pulp. These clusters of fibers will of course retain ink and other contaminants to prevent complete cleaning of the fibers.
SUMMARY OF THE INVENTION
This invention relates generally to the cleaning of fibrous material, and is more particularly concerned with the removal of ink and other contaminants from fibers used in paper making and the like.
The present invention provides a method wherein a fluid suspension of fibers is cleaned by application of a washing fluid. More specifically, a slurry of fibers in fluid suspension is confined, at least one of the walls of the confinement being a screen. Fluidizing means assure that the fibers remain in a fluid state as a washing liquid is passed over the fibers to remove the undesirable contaminants. By proper selection of screens and adjustment of the pressure differential across the fluidized fiber, the undesirable contaminants can be removed without undue loss of fibers.
The apparatus of the present invention includes a first channel for passage of the fluidized fibers, the first channel having at least one wall made up of a screen. A second channel carries washing fluid, the second channel being arranged so that the washing fluid can pass through the screen to the first channel for cleaning the fiber and pass back to the second channel for discharge of the contaminants with the washing fluid.
In the preferred embodiment of the invention, the first channel includes screens on two opposed sides of the channel, and fluidizing means movable within the first channel. The first channel has second channel means contiguously disposed at the two screens, the arrangement being such that washing fluid can be directed along each screen and can be directed from one second channel means, through the first channel, and to another second channel means. The particular flow of the washing fluid is dependent on the pressure differentials used.
The present invention therefore provides a method and apparatus for cleaning fiber wherein the fiber remains in a fluidized state. In this fluidized state, a washing fluid is passed through the fibers to remove the unwanted contaminants from the fibers. The size of the screen, in conjunction with the pressure differential across the screen, will determine the maximum particle size that will be removed, and can be used for fractionating the fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which:
FIG. 1 is an elevational view of a cleaning apparatus made in accordance with the present invention, the front of the passageway being removed to reveal the construction thereof;
FIG. 2 is an enlarged, fragmentary view showing the screen and fluidizing means in the device of FIG. 1;
FIG. 3 is a transverse cross-sectional view through a modified form of apparatus made in accordance with the present invention; and,
FIG. 4 is an enlarged, fragmentary view showing the screen and fluidizing means in the device of FIG. 3.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring now more particularly to the drawings, and to those embodiments of the invention here presented by way of illustration, FIG. 1 includes a central passageway 10 through which the slurry containing the fibers will pass. An inlet 11 allows entry of the slurry, and the cleaned material is discharged from the outlet 12. Those skilled in the art will understand that appropriate pumps or the like shown schematically at 13 will cause the slurry to move. Such apparatus is well known to those skilled in the art and no further showing is thought to be required.
On each side of the passageway 10 there are wash water channels 14 and 15. It will be noted that the channel 14 includes inlets/outlets 16 and 18, and channel 15 includes inlets/outlets 19 and 20. Each of the inlets/outlets 16-20 may be either an inlet or an outlet, or the wash water may be reversed periodically so the various inlets/outlets have different functions at different times. Pumps 17 and 23 are shown for moving the wash water through the channels 14 and 15. This will be discussed in more detail hereinafter.
The wall 21 between the channel 14 and the passageway 10 comprises a screen; and, the wall 22 between the passageway 10 and the channel 15 also comprises a screen. As a result, it will be understood that the wash water from the channels 14 and 15 can pass through the walls 21 and 22 and wash the fibers in the slurry flowing through the passageway 10.
An important feature of the present invention is the maintaining of the fibers in a fluidized state as the slurry flows through the passageway 10. More particularly, the individual fibers are not allowed to agglomerate or to collect on the screen 21 or 22. Anytime the fibers agglomerate, or collect together, it becomes difficult to bathe each fiber sufficiently in wash water and remove all contaminants from the fiber. Thus, the device in FIG. 1 includes fluidizing means generally designated at 24, the fluidizing means 24 including side plates 25 and a plurality of agitators 26. Agitators 26 are made of some impermeable material and are spaced throughout the length of the fluidizing means 24, the fluidizing means 24 in turn extending substantially the full distance of the passageway 10. Between the agitators 26, the fluidizing means 24 is open to the screens 21 and 22 so fluid can pass from within the fluidizing means 24 through the screens 21 and 22 and then to the channels 14 and 15.
At the upper end of the fluidizing means 24, it will be seen that there is a shaft 28, the shaft 28 comprising a means for causing vertical reciprocation of the fluidizing means 24. A conventional mechanism can be utilized to move the shaft 28 back and forth and cause the appropriate motion of the fluidizing means 24. A seal 27 prevents leakage around the shaft 28.
With the above description in mind, it should now be understood that a slurry including fibers to be cleaned will be admitted to the passageway 10 at the entrance 11. Appropriate pump pressure from the pump 13 will be applied to move the slurry from the entrance 11 to the discharge opening 12. As the slurry moves through the passageway 10, the fluidizing means 24 will be moved reciprocally and the plurality of agitators 26 will cause rather severe motion in the fluid to prevent fibers from agglomerating, and to prevent fibers from sticking to either of the screens 21 or 22. Meanwhile, wash water will be passed under pressure provided by pumps 17 and/or 23 through the channels 14 and 15. Arrangement of the apparatus is such that wash water can be directed as desired for the best cleaning. By way of example, wash water may be introduced at the inlet 16 at one end of the channel 14. The wash water may then be removed at the exit 20 of the channel 15. This arrangement will provide a counter flow of the two fluids, for the maximum cleaning ability. The process can be reversed, or two separate streams of wash water can be established, one in the channel 14 and one in the channel 15. It will be understood that the object of the invention is to cause the wash water to engage the slurry in the passageway 10 to pick up the various contaminants from the fibers, and to remove the contaminants in the slurry.
Looking now at FIG. 2 of the drawings, the construction is shown in more detail. The channel 14 is shown as having an outer wall 29, and the inner wall 21 which is a perforate screen. The agitators 26 are shown as angled devices extending into the passageway 10. Thus, as the fluidizing means 24 is moved reciprocally, the agitators 26 will move reciprocally. Agitators 26 are very close to the screen 21, so the agitators 26 will prevent accumulation on the screen somewhat by mechanically removing any fibers that are attached to the screen. More importantly, the motion of the agitators 26 will cause severe turbulence in the fluid within the passageway 10. This turbulence will be sufficient to maintain the fibers in a separated state, and also sufficient to prevent fibers from sticking to the screen 21.
It will be understood by those skilled in the art that used paper will generally be processed into a liquid, primarily by mechanical and chemical means, and some contaminants may be removed through prior processing. It is common to use sedimentation, centrifuging, and preliminary screening to remove some of the contaminants; and, flotation is commonly used for substantial cleaning of the fibers. Any of these conventional steps may be carried out initially, before the fiber is introduced to the apparatus shown in FIG. 1 of the drawings. As is stated above, the prior art techniques do not yield sufficiently clean fiber and something further is needed. The present invention can therefore be used as the final cleaning step, though of course some prior art steps may be omitted, and the apparatus and method of the present invention substituted therefore.
Attention is next directed to FIG. 3 of the drawings which shows a modified form of apparatus made in accordance with the present invention. The cleaning technique is the same as that discussed in connection with FIGS. 1 and 2, but the configuration of the apparatus is somewhat different.
In FIG. 3, there is a cylindrical container 30 having impermeable walls, and an inlet 31. At one end of the cylindrical container 30 there is an outlet designated at 32. Mounted within the container 30, and concentric therewith, there are two screens designated at 34 and 35. The screen 34 is stationarily mounted, and is provided with an inlet 36 and an outlet 38. While the inlet and outlet 36 and 38 are adjacent to each other, a wall 39 separates them for proper flow control.
Considering the description of the prior embodiment, it should be understood that a slurry or the like containing the fibers to be cleaned will be admitted through the inlet 36 so the fibers are contained in the passageway 40, between the two screens 34 and 35. A pump such as the pump 37 will cause the slurry to move around the passageway 40 and to be discharged at the discharge 38. However, while the slurry is moving around the passageway 40, wash water will be admitted through the inlet 31 to fill the channel 41. Appropriate pump pressure from the pump 33 will cause the wash water to move from the channel 41, through the screens 34 and 35 and to the center channel of the device to be discharged through the opening 32. As before, those skilled in the art will understand that the inlet and exit 36 and 38 are reversible, as are the inlet and exit 31 and 32. The flow can be periodically reversed or can be run in either direction as desired.
FIG. 4 is an enlarged section of the screens 34 and 35 and it will be seen that each of the screens includes a plurality of agitators 42. The agitators 42 are here shown as being angled members similar to the agitators 26, the agitators 42 being integrally formed with the screens 34 and 35; but, it will be understood that additional pieces can be attached to an existing screen if desired.
It will therefore be understood that the operation of the apparatus shown in FIGS. 3 and 4 is substantially the same as the operation of the device shown in FIGS. 1 and 2. The screen 35 will be substantially constantly rotated while the apparatus is in use. Rotation of th screen 35 will cause relative motion between the agitators 42 so the slurry in the passageway 40 will be in a highly turbulent flow. As is mentioned above, the turbulence will be sufficient to prevent fibers from collecting on either screen, and will be sufficient to prevent the agglomeration of fibers in the fluid stream. As a result, the wash water passing through the channel 41 and through the screens 34 and 35 will clean the fibers and carry the unwanted contaminants from the passageway 40, through the screen 34 or 35 and into the discharge 32.
It will also be understood by those skilled in the art that contaminants to be removed from the fiber must be small enough to pass through the openings in the screen 21, 22, 34, or 35. There is always a compromise in selecting a screen small enough to prevent the loss of fibers but large enough to allow loss of the unwanted contaminants. Utilizing the method and apparatus of the present invention it should further be recognized that the pressure of the wash water is another variable that will allow removal of more or less of the contaminants and more or less of the fibers.
Through the use of extremely high pressure, which is to say a large pressure differential across a screen, some small fibers might be forced through the screen. With a smaller pressure differential, relatively solid particles such as ink or clay might pass through the screen whereas a fiber not pass through the screen. The present invention therefore provides additional controls, and excellent cleaning of the fibers with minimal loss of the fibers.
It will of course be understood by those skilled in the art that the particular embodiments of the invention here presented are by way of illustration only, and are meant to be in no way restrictive; therefore, numerous changes and modifications may be made, and the full use of equivalents resorted to, without departing from the spirit or scope of the invention as outlined in the appended claims. | The fibers of recycled paper are cleaned by agitating the slurry containing the fibers to maintain the fibers in suspension, and contacting the slurry with wash water to remove ink and other contaminants. The apparatus includes a passageway having screens forming opposite sides of the passageway. Agitators are within the passageway, and create enough turbulence to prevent fibers from settling or agglomerating. Channels adjacent to each screen carry wash water, and pump pressure creates a pressure differential across the screens to cause the wash water to contact the slurry and to be removed from the passageway. | 3 |
RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser. No. 10/637,887, filed Aug. 8, 2003, which claims, as does the present application, priority to U.S. Provisional Application Ser. No. 60/403,464, filed Aug. 14, 2002.
BACKGROUND
[0002] This invention relates to methods and compositions for targeting proteins to secretory lysosomes. The invention further provides methods of use in drug screening assays, and methods of purifying secretory lysosomes.
[0003] Mast cells are specialized secretory cells that release a variety of biologically active substances. Mast cells are found resident in tissues throughout the body, particularly in association with structures such as blood vessels, nerves, and in proximity to surfaces in contact with the external environment (see Metcalfe et al. Physiol Rev. 77:1033-1079, 1997). Mast cell activation may be initiated upon interaction of a multivalent antigen with its specific IgE antibody attached to the cell membrane via its high affinity receptor, FcεRI. Mast cells and basophils play a central role in inflammatory and allergic reactions (see Williams, et al. J. Allergy Clin. Immunol. 105:847-859, 2000). They are known to release potent inflammatory mediators such as histamine, proteases, chemotactic factors and metabolites of arachidonic acid that act on the vasculature, smooth muscle, connective tissue, mucous glands and inflammatory cells.
[0004] The pathways for granule biogenesis and exocytosis in mast cells are still largely obscure (Griffiths, G. M. et al., Biochem Biopys Res Commun. 222(3):802-808, 1996; Masuda et al., FEBS Lett. 470:61-64, 2000; Baram, D. et al., J Immunol. 167(7):4008-4016, 2001). Mast cells contain structures known as secretory lysosomes which are a mixture of lysosomes and secretory granules (Stinchcombe and Griffiths, J Cell Biol. 146(1):1-6, 1999). The mast cell granule can be described as a modified lysosome, specialized for fusion with the plasma membrane, and with other lysosomal granules, after receptor activation. Although similar secretory lysosomes are found in hematopoietic cells, little is known about the mechanisms by which these organelles receive and deliver their cargo. For example, Riesbeck et al. (WO 98/42850) disclose protein targeting to endothelial cell Weibel-Palade bodies. Weibel-Palade bodies contain the adhesion molecule P-selectin.
[0005] There are two categories of inflammatory mediators in mast cells and basophils, preformed mediators and newly formed mediators. Preformed mediators, stored in the cytoplasmic granules of rodent or human mast cells, include histamine, proteoglycans, cytokines, serine proteases, carboxypeptidase A and small amounts of sulfatases and exoglycosidases (Metcalfe et al., Physiol Rev. 77(4):1033-1079, 1997). Histamine acts on a set of receptors (H1, H2, H3, H4) on cells and tissues and is rapidly metabolized extracellularly. Proteoglycans may function to package histamine and basic proteins into secretory granules, and in human mast cells may stabilize the protease tryptase. Neutral proteases, which account for the vast majority of the granule protein, serve as markers of mast cells. Newly generated mediators, often absent in resting mast cells, consist of arachidonic acid metabolites, principally leukotriene C and prostaglandin D. These mediators are typically produced during IgE receptor activation. Of particular interest in humans is the production of tumor necrosis factor (TNF), Interleukin (IL)-4, IL-5 and IL-6.
[0006] Proteases are the major protein constituent exocytosed from activated mast cells (Huang et al., J Clin Immunol. 18:169-183, 1998). Tryptases, chymases, and carboxypeptidases are the three major families of proteases stored in the secretory granules of mast cells. Chymases are part of the serine protease family. Immunohistochemical localization indicates that they are only synthesized in mast cells (Beil et al., Histol Histopathol. 15(3):937-946, 2000). Human, primate, and dog chymase generate angiotensin II (Ang II) from Ang I, while mouse and rat chymases degrade Ang II (Fukami et al., Curr Pharm Des. 4(6):439-453, 1998). Chymase also degrades extracellular matrix, and processes procollagenase, inflammatory cytokines and other bioactive peptides. As a result, chymase plays important roles in inflamed tissues through its proteolytic activities.
[0007] In human cells, genes encoding two chymotryptic enzymes (chymase and Cathepsin G-like protease) and one mast cell carboxypeptidase enzyme and at least two genes encoding tryptase peptides have been detected. The gene encoding chymase is closely linked to the gene encoding cathepsin G, an enzyme apparently expressed in mast cells, and to the genes encoding granzymes. Mucosal (MC)-type mast cells contain tryptase, chymase, cathepsin G-like protease and mast-cell carboxypeptidase. The biological function of mast cell neutral proteases, like mast cells themselves, remains to be fully clarified. For example, on-going mast cell activation in asthma appears to be a characteristic of this chronic inflammatory disease.
[0008] In murine mast cells, five chymases (Mouse Mast Cell Protease (MMCP)-1, -2, -3, -4, and -5), one mast cell carboxypeptidase and two tryptases (MMCP-6 and -7) have been reported. In rodents, the protease composition of mast cell subsets differs. In rats two isoforms of chymase, Rat Mast Cell Protease (RMCP) I (Lagunoff and Pritzl Arch Biochem Biophys. 173(2):554-563, 1976) and RMCP II (Kido et al, Arch Biochem Biophys. 239(2):436-443, 1985) were found to distinguish the mast cells in mucosal surfaces (RMCP-II positive), from other mast cells (RMCP-I positive) (Gibson and Miller Immunology 58(1):101-104, 1986). More recently, two additional serine proteases were isolated by PCR amplification from rat serosal MC: the rat tryptase (the counterpart of MMCP-6) and an additional chymase named RMCP III (Lutzelschwab et al., J Exp Med. 185(1):13-29, 1997). The latter protease is the rat counterpart of mouse MMCP-5.
[0009] Scientists have reported on a protein, Rab37, that can localize to the surface of mast cell granules when fused to green fluorescent protein (GFP) and is over-expressed in bone-marrow derived mast cells (see Masuda et al., FEBS Lett. 470:61-64, 2000). Rab37 appears to localize to the cytoplasmic surface of granules. However, Masuda does not teach the use of Rab37 to target granules.
[0010] Until the present invention, there have been no reports on the use of a targeting moiety to localize proteins to secretory lysosomes. Current state of the art employs indirect methods for the detection of granule content or exocytotic activity. For example, mast cell granules have been studied by monitoring their content with antibodies, or measuring the activity of enzymes such as hexosaminidase (see Schwartz et al. J. Immunol. 123:1445-1450, 1979; and Dragonetti et al. J. Cell Sci. 113:3289-3298, 2000). Other indirect methods relate proteins and their functions to other secretory compartments such as the endoplasmic reticulum, Golgi and trans Golgi network (see Donaldson and Lippincott-Schwartz, Cell 101:693-696, 2000). Therefore, a targeting moiety localizing proteins to the inner core of mast cell secretory lysosomes is a significant advancement in mast cell research and drug discovery.
[0011] Current methods that attempt to quantify the release of mediators upon degranulation of cells containing secretory lysosomes are lengthy and costly (see, for example, Schwartz et al., J Immunol. 123:1445-1450, 1979 and Schulman et al., J Immunol. 131:2936-1941, 1983). The present invention overcomes these obstacles such that not only is the content of secretory lysosomes quantified, but also the movement of secretory lysosomes is monitored in real time.
[0012] Until the present invention, no methods were amenable for High Throughput Screening (HTS) to screen for modulators of secretory lysosomes. Current state of the art does not allow direct monitoring of cell degranulation in an HTS setting. For example Demo et al. (Cytometry, 36(4):340-8, 1999) disclose assays that require several biochemical measurements and many steps that consume time, energy and likely have low reproducibility due to the reagents used (histamine, tryptase, hexosaminidase). For example, histamine is known to have a poor dynamic range for quantification in HTS setting. Other methods have been used to monitor cell degranulation using fluorescent probes such as acridine orange (see Love Histochemistry 62:221-225, 1979) but these assays lack specificity for the exocytotic process and poor-signal to noise ratios (see Demo et al. Cytometry, 36(4):340-8, 1999). One group has disclosed a quantitative measurement of cell degranulation using a flow cytometric annexin-V binding assay (see Demo et al. Cytometry, 36(4):340-8, 1999). Flow cytometry however, is not amenable to HTS format.
[0013] Current art provides protocols to obtain subcellular fractions enriched in mast cell granules by fractionation of cell homogenates on Percoll or sucrose gradients (Lindmark et al., J Leukocyte Biol. 66:634-643, 1994). Advantageously, the present invention provides methods to purify secretory lysosomes to a higher degree than currently achieved. The increased level of purification achieved by the present invention is crucial for proteomics studies aimed at the identification of novel drug discovery targets involved in cell activation.
BRIEF SUMMARY
[0014] The present invention relates to methods for localizing secretory lysosomes in real-time within a cell using a targeted molecule. Such methods are useful for many purposes, including but not limited to, studying secretory lysosome movement and fusion, directly monitoring exocytosis, developing cellular screens for cell activation and purification of secretory lysosomes.
[0015] Prior to the present invention, there were no existing direct methods of targeting protein to secretory lysosomes. Mast cell secretory lysosomes are specialized organelles that contain proteases, heparin, histamine and several cytokines. Previously, secretory lysosomes were studied by indirect methods such as monitoring their content with antibodies or measuring the activity of enzymes such as hexosaminidase.
[0016] The present invention relates to a secretory targeting fusion moiety comprising a polypeptide that specifically localizes to a secretory lysosome and a label polypeptide. The present invention also relates to a secretory targeting fusion moiety comprising a nucleotide sequence encoding a polypeptide that specifically localizes to a secretory lysosome and a nucleotide sequence encoding a label polypeptide.
[0017] The present invention further relates to a secretory targeting fusion moiety comprising a protease selected from the group consisting of tryptases, chymases, and carboxypeptidases, preferably Mouse Mast Cell Protease (MMCP)-1, -2, -3, -4, -5, -6, and -7; Rat Mast Cell Protease (RMCP) I and RMCP II; human chymases; human tryptases; Cathepsin G-like protease; Cathepsin G; carboxypeptidase A; and hexosaminidase; more preferably RMCP II.
[0018] The invention further related to a cell comprising a secretory targeting fusion moiety of the present invention. In an embodiment, the label polypeptide is a fluorescent molecule. In a specific embodiment, the fluorescent molecule is Discosoma sp. red fluorescent protein or green fluorescent protein. In an embodiment, the cell of the invention is selected from the group consisting of: mast cells, basophils, hemopoietic cells, melanocytes, and goblet cells. In a specific embodiment, the cell is a mast cell.
[0019] In a particular embodiment, the invention relates to a cell line expressing a secretory lysosome targeting fusion moiety as deposited with the American Type Culture Collection and assigned accession number PTA-4571.
[0020] In one embodiment of the present invention, there is disclosed a method for detecting and quantifying degranulation comprising: (a) incubating a cell expressing a secretory lysosome targeting fusion moiety comprising a label molecule in the presence of a cell activator; (b) incubating the cell expressing the secretory lysosome targeting fusion moiety comprising a label molecule in the absence of the cell activator; and (c) detecting and quantifying the release of label in the supernatant in the presence of the cell activator compared to the release of label in the supernatant in the absence of the cell activator, wherein an increase in the release of label in the supernatant in the presence of the cell activator indicates degranulation.
[0021] In another embodiment of the present invention, there is disclosed a method for detecting and quantifying inhibition of degranulation comprising: (a) incubating a cell expressing a secretory lysosome targeting fusion moiety comprising a label molecule with a cell activator in the presence of a test substance; (b) incubating the cell expressing the secretory lysosome targeting fusion moiety comprising a label molecule with the cell activator in the absence of the test substance; and (c) detecting and quantifying a change in the release of label in the supernatant in the presence of the test substance compared to the release of label in the supernatant in the absence of test substance, wherein a decrease in the release of label in the supernatant in the presence of test substance indicates inhibition of degranulation.
[0022] In another embodiment of the present invention, there is disclosed a method for detecting and quantifying degranulation at the single cell level comprising: (a) incubating a cell expressing a secretory lysosome targeting fusion moiety comprising a label molecule in the absence of a cell activator; (b) detecting and quantifying the amount of label in the absence of a cell activator, (c) incubating the cell of step (a) in the presence of a cell activator; (d) detecting and quantifying the amount of label in the presence of the cell activator; and (e) detecting a change in the amount of label in the cell in the presence of the cell activator compared to the amount of label in the cell in the absence the cell activator, wherein a decrease in the amount of label indicates degranulation.
[0023] In another embodiment of the present invention, there is disclosed a method for detecting and quantifying degranulation at the single cell level comprising: (a) incubating a cell expressing a secretory lysosome targeting fusion moiety comprising a label molecule in the presence of a cell activator; (b) detecting and quantifying the amount of label in the presence of the cell activator, (c) incubating the cell of step (a) in the presence of the cell activator and a test substance; (d) detecting and quantifying the amount of label in the presence of the cell activator and the test substance; and (e) comparing the amount of label in the cell in the presence of the test substance to the amount of label in the cell in the absence the test substance, wherein an increase in the amount of label in the presence of the test compound indicates degranulation.
BRIEF DESCRIPTION OF THE FIGURES
[0024] FIG. 1 . Stable expression of RMCP-DsREd in RBL-2H3 cells. Cells were transfected by electroporation with the RMCP-DsRED vector (“DsRED”, Discosoma sp. red fluorescent protein). Cells were then submitted to Geneticin® (G-418, GIBCO Invitrogen Corp., Carlsbad, Calif.) selection for 10 days. FIG. 1 shows FACS analysis of control RBL-2H3 population compared to the selected pool of cells expressing RMCP-DsRED.
[0025] FIG. 2 . FACS analysis of the clone RBL-RMCP/2C2. Individual clones from the cellular pool expressing RMCP-DsRED were generated. This figure shows FACS analysis of the RBL-2H3 parental cells compared to the clone RBL-RMCP/2C2.
[0026] FIG. 3 . Stable expression of RMCP-DsRED recombinant protein in RBL-2H3 cells. RBL-2H3 cells were stably transfected with an expression vector for the DsRED protein alone or the RMCP-DsRED fusion protein. After the selection process, individual clones were analyzed by confocal microscopy to determine subcellular distribution of the recombinant protein. A) Shows confocal image of cells expressing the DsRED protein and its cytoplasmic expression. B) Shows a confocal image of cells expressing the RMCP-DsRED. fusion protein. The punctate fluorescence correlates with the localization of granules or secretory lysosomes in mast cells or basophils.
[0027] FIG. 4 . The RMCP-DsRED construct targets secretory lysosomes and granules in RBL 2H3 cells. Cells stably expressing the RMCP-DsRED fusion protein were treated with the LysoTracker® probe. Left panel shows intracellular localization of secretory lysosomes and granules using the LysoTracker® probe. Middle panel shows the distribution of the RMCP-DsRED fusion protein. The overlay of LysoTracker® and RMCP-DsRED images (right panel) shows colocalization of the RMCP-DsRED with the secretory lysosome and granule compartments.
[0028] FIG. 5 . RMCP-DsRED is released upon IgE stimulation of RBL 2H3 cells. RBL 2H3 cells stably expressing the RMCP-DsRED protein (clone RBL-RMCP/2C2) were stimulated with IgE and antigen (DNP-HSA). Hexosaminidase and histamine are two granule markers that are released from the cells within minutes after stimulation. Quantification of the fluorescence released after stimulation shows a rapid release of the RMCP-DsRED fusion protein followed by a slower phase of release 90 minutes after stimulation.
[0029] FIG. 6 . Flow cytometric analysis of fluorescent granules from RBL-2H3 clones stably expressing RMCP-DsRED protein. Cells expressing DsRED alone (control) or RMCP-DsRED were submitted to subcellular fractionation on a Percoll gradient. The fraction containing the secretory lysosome and granules was then analyzed by organelle flow cytometry. Cells expressing DsRED (left panel) showed no fluorescent lysosomes or granules compared to cells expressing RMCP-DsRED (right panel).
[0030] FIG. 7 . Purification of fluorescent secretory lysosomes and granules using FACS sorting. Fluorescently labeled secretory lysosomes and granules gated in FIG. 6 (right panel) were sorted by flow cytometry and assayed for hexosaminidase content. Hexosaminidase specific activity is shown for the post nuclear supernatant (PNS), the lysosomal/granule fraction isolated by Percoll gradient and for the FACS sorted material.
[0031] FIG. 8 . Live cell imaging of RBL-2H3 cells expressing RMCP-DsRED following IgE stimulation. Live RBL-RMCP/2C2 cells were visualized by confocal microscopy. Cells were imaged at time 0 and then stimulated with IgE and antigen (DNP-HSA). Cells were incubated for a total of 2 hours and images were taken at various time points. The 15 min., 1 h and 2 h time points are shown.
DETAILED DESCRIPTION OF THE INVENTION
[0000] 1. Definitions
[0032] The following definitions are provided to facilitate understanding of certain terms used herein:
[0033] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise.
[0034] By “cells” it is meant to include cells in any form, including, but not limited to, cells retained in tissue, cell clusters and individually isolated cells.
[0035] By “cell line” it is meant cells capable of stable growth in vitro for many generations.
[0036] By “clone” it is meant a population of cells derived from a single cell or common ancestor by mitosis.
[0037] By “degranulation” it is meant movement and exocytosis of secretory lysosomes. By “polypeptide” it is meant peptide or protein and variants thereof.
[0038] By “secretory lysosome” it is meant a dual-function organelle that is used as both the lysosome (for degradation) and for storage of secretory proteins of the cell and which shares many features with both conventional lysosomes and secretory granules, such as structure and content.
[0039] By “secretory lysosome targeting fusion moiety” it is meant a moiety comprising: (a) a polypeptide that specifically localizes to a secretory lysosome or a nucleotide sequence encoding such polypeptide and (b) a label polypeptide or nucleotide sequence encoding such label polypeptide.
[0040] By “secretory lysosome targeting moiety” it is meant a polypeptide that specifically localizes to a secretory lysosome or a nucleotide sequence encoding such polypeptide.
[0041] By “variant” it is meant a sequence, such as a polypeptide, that differs from another sequence, but retains essential properties thereof, that is, properties for which the sequence is utilized in its application (e.g., protease activity). For example, a variant of a polypeptide may differ in amino acid sequence by one or more substitutions, additions, and deletions from the reference polypeptide. By “variant” it is also meant to include fragments of a full length sequence that retain essential properties thereof.
[0000] 2. The Methods and Constructs
[0042] The present invention overcomes many of the problems associated with prior art methods for detection and monitoring of secretory lysosome content and exocytotic activity. By transfecting cells with a moiety comprising a nucleotide sequence encoding a secretory lysosome-specific protein and a nucleotide sequence encoding a label molecule, the present invention permits the study of the movement of secretory lysosomes and the release of their contents in real time and secretory lysosome quantification in living cells.
[0043] Cells that may be used in the present invention include cell lines and primary cells that have secretory lysosomes, including but not limited to mast cells, basophils, hemopoietic cells, melanocytes, and goblet cells. In a preferred embodiment, the cells are mast cells.
[0044] In one embodiment, a cell line expressing a secretory lysosome targeting moiety is designated RBL-RMCP/2C2 (accession no. PTA-4571, deposited on Aug. 7, 2002 with the American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 200110-2209 under the terms of the Budapest Treaty).
[0045] The secretory lysosome targeting moiety of the present invention localizes in secretory lysosomes. The secretory lysosome targeting moiety of the present invention may comprise constituents of secretory lysosomes such as proteases, for example, tryptases, chymases and carboxypeptidases including but not limited to: Mouse Mast Cell Protease (MMCP)-1, -2, -3, -4, -5, -6, and -7; Rat Mast Cell Protease (RMCP) I and RMCP II; human chymases; human tryptases; Cathepsin G-like protease; Cathepsin G; carboxypeptidase A; hexosaminidase; or polypeptides thereof or polypeptides encoded by related genes or orthologues. In an embodiment, the secretory lysosome targeting moiety comprises RMCP II.
[0046] The secretory lysosome targeting moiety of the present invention can further comprise any polypeptide of interest or nucleotide sequence encoding such polypeptide. In the screening and detection methods of the present invention, the polypeptide or nucleotide sequence encoding such polypeptide is a label, preferably a fluorescent molecule, e.g., Discosoma sp. red fluorescent protein (DsRED) or green fluorescent protein (GFP).
[0047] A label molecule can include, but is not limited to, a luminescent molecule (e.g. luciferase), an enzyme (e.g. horse radish peroxidase, β-galactosidase), a fluorescent molecule (e.g., Discosoma sp. red fluorescent protein (DsRED) or green fluorescent protein (GFP).
[0048] In the therapeutic methods of the invention described below, the secretory lysosome targeting moiety can further comprise any therapeutic polypeptide or nucleotide sequence encoding such polypeptide of interest, including but not limited to enzymes, cytokines, growth factors, and recombinant antibodies (single chains).
[0049] The present invention also provides methods for identifying compounds that modulate degranulation using the secretory lysosome targeting fusion moieties of the invention. For example, a cell of the invention expressing a secretory lysosome targeting fusion moiety comprising a label molecule is incubated with a cell activator in the presence and absence of a test substance. A change in the release of fluorescence in the supernatant in the presence of the test substance would indicate that the test substance modulates degranulation, for example, an increase in the release of fluorescence in the supernatant indicates degranulation. In a preferred embodiment, the secretory lysosome targeting fusion moiety comprises a fluorescent label molecule.
[0050] Cell activators include but are not limited to: IgE and a multivalent antigen, phorbol myristate acetate (PMA), ionomycin, compound 48/80, toll-like receptors, and protease receptors. In one embodiment of the invention cell activators are selected from the group consisting of: IgE and a multivalent antigen, phorbol myristate acetate (PMA), and ionomycin.
[0051] In another embodiment, the present invention provides methods for increasing the purity of secretory lysosome preparations using the secretory lysosome targeting fusion moieties.
[0052] Preferably, a cell line transfected with a secretory lysosome targeting fusion moiety comprising a fluorescent molecule is fractionated by methods known in the art (e.g., Percoll or sucrose gradient) to obtain subcellular fractions enriched in secretory lysosome. The secretory lysosome-rich fraction is then further purified using fluorescence activated cell sorting (FACS).
[0053] In another embodiment, the present invention provides methods for studying secretory lysosome maturation, biosynthesis, cell differentiation, migration and activation in vivo using a secretory lysosome targeting moiety further comprising a reporter gene.
[0054] In another embodiment, the present invention provides methods for studying and quantifying exocytosis (degranulation) in real time, at a single cell level using a secretory lysosome targeting fusion moiety, preferably comprising a fluorescent label molecule, wherein detection and quantification is performed using fluorescence or confocal microscopy, for example, using a Cellomics ArrayScan® System (Cellomics, Inc., Pittsburgh, Pa.). In these methods, for example, fluorescence would be detected before and after stimulation of a cell transfected with a fluorescent marker and a secretory lysosome targeting moiety, wherein a reduction in fluorescence indicates degranulation. These methods, therefore can be used to screen for compounds that inhibit the release of secretory lysosomes.
[0055] In another embodiment, the present invention provides methods for delivery of therapeutic polypeptides in vivo using a secretory lysosome targeting fusion moiety comprising a therapeutic polypeptide. In one embodiment, a cell line transfected with the therapeutic secretory lysosome targeting fusion moiety is encased in an immunoisolation device and implanted in a subject.
[0056] The screening methods of the present invention may be adapted to High Throughput Screening (HTS) and Ultra High Throughput Screening (UHTS). The HTS and UHTS can employ, for example, a Zymark Allegro™ modular robotic system (Zymark Corp., Hopkinton, Mass.) to dispense reagents, buffers, and test compounds into either 96-well or 384-well black microtiter plates (from Dynex (Dynex Technologies, Denkendorf, Germany) or Corning (Corning Costar, Cambridge, Mass.), respectively).
EXAMPLES
[0057] The following examples are provided to illustrate the invention, but not to limit its scope. Other variants of the invention will be readily apparent to one of ordinary skill in the art.
Example 1
Cloning of RMCP II in the Expression Vector pDsRED1-N1
[0058] The sequence encoding RMCP II was retrieved from GenBank (accession no. J02712; Benfey et al. JBC 262:5377, 1987). RMCP II was cloned by polymerase chain reaction (PCR). The rat basophilic leukemia (RBL-2H3) cell line (accession no. CRL-2256, American Type Culture Collection (ATCC), Manassas, Va.) was used as a source of RNA. The reverse transcriptase reaction (first strand cDNA synthesis) was done using the Superscript™ amplification system by GIBCO BRL (catalog no. 18089-011, GIBCO BRL, Invitrogen Corp., Carlsbad, Calif.) according to the manufacturer's instructions. The PCR amplification was performed on first strand cDNA (from previous step) using the following oligos:
(SEQ ID NO:1) 5′-TCAGATCTCGAGATGCAGGCCCTACTATTCCTG-3′ and (SEQ ID NO:2) 5′-CTGCAGAATTCGGCTACTTGTATTAATGACTGCAT-3′.
[0059] The PCR conditions were as follows: 94° C. (30 sec)-62° C. (30 sec)-72° C. (50 sec). The PCR product was purified and digested with the restriction enzymes XhoI and EcoRI. These restriction sites are provided by the oligos. The fragment was then cloned in the same sites of the pDsRED 1-N 1 vector from Clontech (catalog no. 6921-1, BD Biosciences Clontech, Palo Alto, Calif.). This cloning strategy results in the full length RMCP II cDNA in-frame with the N-terminus of the cDNA for the fluorescent protein DsRED. The sequence identity of the recombinant vector, RMCP-DsRED, was confirmed by DNA sequencing.
Example 2
Stable Expression of RMCP-DsRED Recombinant Protein in RBL-2H3 Cells
[0060] RBL-2H3 cells (8×10 6 ) were transfected with the RMCP-DsRED vector (45 μg) by electroporation (Guillemot et al. JCB 110:2215-2225, 1997). The conditions for the electroporation were 300 V and 960 μF in a volume of 800 μl. The transfected cell line is designated RBL-RMCP/2C2. Transfected cells were transferred to the appropriate culture media and incubated for 48 h. Positive clones were then selected by the addition of 1 mg/ml of active Geneticin® (GIBCO BRL, Invitrogen Corp., Carlsbad, Calif.). Ten days after transfection, the cells were analyzed by fluorescence activated cell sorting (FACS). As seen in FIG. 1 , a population of cells positive for red fluorescence was detected. Individual clones from the cell population were isolated by FACS and amplified. As seen in FIG. 2 , RBL-RMCP/2C2 is a positive clone expressing the RMCP-DsRED fusion protein.
Example 3
Expression of RMCP-DsRED Fusion Protein in Granules
[0061] The subcellular localization of the RMCP-DsRED protein from the RBL-RMCP/2C2 clone was analyzed by confocal microscopy. A cellular clone expressing the pDsRED vector alone was used as control. As shown in FIG. 3 , cells transfected with the pDsRED control vector expressed the DsRED protein in the cytoplasm (diffuse fluorescence). In contrast, RMCP-DsRED fusion shows punctuate expression in proximity to the plasma membrane. This pattern correlates with the localization of granules in mast cells or basophils. The LysoTracker® probe (Molecular Probes, catalog no. L-7526) is a weakly basic amine that selectively accumulates in cellular compartments with low internal pH which include lysosomes and dense core granules (Sreyer, J. A. et al. Nature 388:474-478, 1997). As seen in FIG. 4 , in the RBL-RMCP/2C2 clone, the LysoTracker® probe co-localizes with the RMCP-DsRED fusion protein. This result confirmed that the RMCP-DsRED fusion protein is targeted to granules.
Example 4
Release of Red Fluorescence Upon Cell Activation
[0062] Mast cells and basophils respond to IgE and antigen stimulation by the rapid release (within minutes) of their granule content into the extracellular milieu. A standard assay in the field is to stimulate the RBL-2H3 cell line with an antigen-specific IgE molecule and then cross-link the IgE receptor by the addition of the corresponding antigen (Roa M. et al. J. Immunol. 159:2815-2823, 1997). The release of histamine and β-hexosaminidase are typically used as markers to monitor degranulation (Schwartz L. B. et al. J. Immunol. 123:1445-1450, 1979). As expected, when the RBL-RMCP/2C2 cells are stimulated with a mouse anti-DNP (dinitrophenyl) IgE followed by stimulation with DNP-HSA (DNP antigen coupled to human serum albumin) they release both histamine and β-hexosaminidase within minutes ( FIG. 5 ). As shown in FIG. 5 , the RBL-RMCP/2C2 cells also release red fluorescence upon stimulation. The fluorescence release was measured from the supernatant of the cell culture (in a 96-well plate format) at the indicated time using an LJL fluorescence plate reader. The kinetics of histamine, β-hexosaminidase and fluorescence release are the same.
Example 5
Purification of Granules by FACS
[0063] Cell homogenates were fractionated on Percoll or sucrose gradients to obtain subcellular fractions enriched in mast cell granules (Kruger P. G. et al., Exp. Cell Res. 129:83-93, 1980). Using the RBL-RMCP/2C2 cell line, the granule-rich fraction was further purified by FACS. As shown in FIG. 6 , a distinct fluorescent population was detected in the granule fraction isolated from RBL-RMCP/2C2 cells as compared to a control cell line. The positive (gated) population was then separated from the total fraction by organelle sorting (Fialka I. et al. J. Biol. Chem. 274:26233-26239, 1999). As shown in FIG. 7 , hexosaminidase specific activity was substantially increased after sorting. Thus, this step contributed to a substantial increase in the purity of the granule fraction.
Example 6
Live Imaging of Cells Expressing RMCP-DsRED Following IgE and Antigen Stimulation
[0064] Live RBL-RMCP/2C2 cells were visualized by confocal microscopy. Cells were sensitized with anti-DNP IgE, imaged at time 0 and then stimulated with antigen (DNP-HSA). Cells were incubated for a total of 2 hours and images were taken at various time points. The 15 min, 1 h and 2 h time points are shown in FIG. 8 . As shown in FIG. 8 , degranulation can be observed in real time at the single cell level.
Example 7
Quantifying the Inhibition of Degranulation by a Test Substance in RBL-RMCP/2C2 cells
[0065] Cells are seeded in 96-well plates at a density of 2×10 4 cells per well and incubated overnight. Cells are then washed twice in culture media and incubated for 2 hours at 37° C. in culture media containing the test substance (concentrations ranging from 1 mM to 1 pM) and 1 μg/ml of anti-DNP IgE monoclonal antibody (SPE7 clone, Sigma). The cells are then washed twice in Tyrode's buffer (10 mM Hepes, pH 7.4, 130 mM NaCl, 5 mM KCl, 1.4 mM CaCl 2 , 1 mM MgCl 2 , 5.6 mM glucose, and 0.1% BSA) and then stimulated with 100 ng/ml DNP-HSA (Sigma) in Tyrode's buffer for one hour. Aliquots (100 μl) from the culture supernatants are analyzed for release of red fluorescence. The red fluorescence is detected on an LJL Bioanalyst (LJL Biosystems, Sunnyvale, Calif.) set at 530 nm for excitation and 580 nm for emission.
[0066] All publications and patents cited herein are incorporated by reference in their entireties. | This invention relates to methods and compositions for targeting proteins to secretory lysosomes. The invention further provides methods of use in drug screening assays, and methods of purifying secretory lysosomes. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the National Stage of International Application No. PCT/EP2014/052139, having an International Filing Date of 4 Feb. 2014, which designated the United States of America, and which International Application was published under PCT Article 21(s) as WO Publication No. 2014/122124 A1, and which claims priority from and the benefit of French Application No. 1350988, filed 5 Feb. 2013, the disclosures of which are incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] The presently disclosed embodiment relates to a device for retaining a tank in an aircraft and more particularly one suited to holding cryogenic propellant tanks in a fuselage of an aircraft such as an airplane and notably a spaceplane. Such a device, which in the relevant art is referred to as a “supporting device”, is notably suited to supporting tanks of cylindrical or conical shape supplying a rocket motor of a spaceplane with propellant.
[0004] It affords a solution to applications that require cryogenic liquids to be transported in aircraft under very stringent space and mass constraints and for which usage and test cycles require that the tanks be set down and refitted at short order.
[0005] It particularly finds an application in spacecrafts which carry large quantities of cryogenic propellants used for the rocket propulsion of these craft and for which optimizing the dry weight is a prime concern.
[0006] 2. Brief Description of Related Developments
[0007] In the field of space the non-structural cryogenic tanks of rocket stages are conventionally interfaced with the bearing structure of the stage that accommodates them via two skirt-like mounting devices situated above and below the tank.
[0008] These devices are designed to allow the tank fixing points to move radially as a result of thermal deformations of the cryogenic tank. The upper interface in this context allows longitudinal movements of the tank fixing points whereas the rear or lower interface on the other hand is longitudinally fixed.
[0009] These interface devices may be cones or link rod assemblies, as in the case of the inter-tank interface of the Ariane 5 cryogenic upper stage ESCA, as depicted in FIG. 1 which is a perspective half-view in which a tank A is restrained by link rods B on a structure C or may also be assemblies of connecting sheets.
[0010] These solutions entailing numerous connecting elements allow good distribution of load at the interfaces, but have the major disadvantages of a not-insignificant impact on the mass of the craft and the need for lengthy operation times for assembling and dismantling the interfaces.
[0011] Furthermore, the conventional launcher fixings are designed for forces essentially oriented along the axis of the tank, whereas for a spaceplane, the forces are not along this axis alone but also perpendicular to this axis and in terms of role. As a result, launcher solutions cannot be applied unmodified to an aircraft of the spaceplane type.
[0012] These interface devices are not, however, particularly well suited to compensating for the stresses induced by differential thermal expansions which are non-zero. Furthermore, they cause thermal losses that are not insignificant.
[0013] Finally, these devices are applicable very little if at all to installations in which the volume available for the supporting device is very small.
[0014] In the field of maritime transport, document U.S. Pat. No. 3,659,817 A describes a solution for supporting a cryogenic tank which consists of a set of fixings, at least 2×4 fixing elements, oriented tangentially to the skin of the cryogenic tank and perpendicular to the main axis thereof so as to avoid the generation of bending stresses in this same skin under the effect of the variations in orientation of the loads caused by the continuous motion of a ship at sea.
[0015] That document does not describe means suited to reacting the longitudinal loads along the tank main axis. Furthermore, the recurrent movements considered are of smaller amplitude by comparison with what a spaceplane for example might encounter between the aeronautical phase and the space phase, particularly when aeronautical certification requirements are taken into consideration. Finally, some of the support devices proposed for equalizing the stresses may prove highly penalizing in terms of mass when applied to rocket propulsion tanks. This is because this solution, like most of the solutions usually adopted for the maritime support of cryogenic tanks, essentially for liquid natural gas, is unable to optimize the entire tank+bearing structure+support elements mass package to the level required for the space or aeronautical domain. This is notably explained by the fact that the tanks used in maritime transport have a capacity of several hundreds of m3 and therefore dimensions of an order of magnitude greater than the tanks of a capacity of just a few m3 to which the presently disclosed embodiment relates. Likewise, thermal losses, which are negligible in comparison with the volumes transported in maritime transport, are no longer negligible on the scale of aeronautical craft and spacecraft.
[0016] In the field of the mounting of tanks in an airplane, documents U.S. Pat. No. 3,951,362 A and U.S. Pat. No. 3,979,005 A which apply to a toroidal tank describe support means which comprise supports for reacting shear forces distributed on the circumference of a cryogenic tank.
[0017] These supports consist of sheets of a curved shape to give them the flexibility needed to allow radial relative deformations and guarantee that they work purely in shear.
[0018] These supports, suited to tanks with toroidal bottoms, constitute just part of the support device which is more complex and requires either the addition in the airplane of a support structure of conical type, which is bulky and penalizing in terms of mass, or that the forces at the front of the tank be reacted on a pressurized end wall that is designed and engineered to perform this function and is therefore once again heavy and bulky.
SUMMARY
[0019] The use of cryogenic propellants to afford all or some of the propulsion of an aircraft, as is the case for example with a spaceplane that has a rocket motor for carrying out suborbital or orbital missions, entails the installation of dedicated tanks, preferably in the fuselage of this aircraft.
[0020] In the light of the prior art, the presently disclosed embodiment proposes a device for supporting and holding a tank in an aircraft and in particular a spaceplane, which adds little volume to the tank, which is suited to supporting and holding tanks confined in small volumes and which allows the tanks to be fitted/removed a number of times over the life of the aircraft.
[0021] The ratio of operational mass to dry mass to a first order governs the performance achievable by such craft, and so it is essential to design a device for installing cryogenic tanks in the fuselage that is as optimal as possible in terms of mass.
[0022] In the same spirit, any unused volume is to be proscribed, and the diameters of the cryogenic tanks are defined to be as close as possible to the diameters of the fuselage, thus placing great constraints on how interface components are arranged.
[0023] Be that as it may, it needs to remain possible for the latter to be inspected for each flight, and inspected easily, and likewise removed and refitted, something which is likely to occur at least a few times in the life of the airplane.
[0024] Still with the concern of guaranteeing the desired performance, the device needs in particular to minimize the evaporation of cryogenic propellants through thermal losses between the tanks and the bearing structure.
[0025] Finally, the cryogenic tanks' interface fixings need to be capable of meeting the conditions mentioned hereinabove without generating thermomechanical stresses caused by the differential expansions between the tanks and their surroundings, and in spite of the high acceleration loadings applied in varying directions. These fixings indeed need to meet the certification requirements which notably specify the accelerations that the structure needs to be able to withstand in the event of an emergency landing, and the particular profile of the orbital or suborbital missions which comprise a rocket-propulsion phase which nominally occurs on each flight.
[0026] One subject of the presently disclosed embodiment is a device for supporting tanks for the storage or transportation of cryogenic liquids in a fuselage of an airplane and/or spacecraft, including suborbital craft, that provides an answer to the problem set explained hereinabove.
[0027] This device allows all of the following:
[0028] relatively quick and easy fitting and removal of the tanks confined to a very tight space, and quick inspection operations;
[0029] limitation on the loads applied to the airplane structure and especially to the propellant tanks in spite of significant differential thermal expansions, notably high striction/shortening of the tanks subjected to the cryogenic temperatures and despite a highly varying loading profile: significant accelerations applied along the axis of the tank, for example during space propulsion phases, or at right angles to the axis of the tank, for example during conventional aeronautical phases with high vertical load coefficients or steep-descent phases;
[0030] optimization of the attachment points coherent with the main axes and bearing structures of the airplane;
[0031] minimization of the overall mass impact, at the attachment points as such, but also of the reinforcers needed at the level of the airplane structure and of the structural parts of the tanks; and
[0032] an answer to the civil aviation certification requirements, particularly those relating to tolerance of breakdowns and those relating to safety in the event of sharp decelerations or emergency landings.
[0033] The tanks in question are particularly non-structural tanks of cylindrical or conical shape with spherical or elliptical ends.
[0034] They are equipped with structural fixing and reinforcing elements such as a skirt or hoops, capable of reacting the interface forces and located at the front and rear of the tank.
[0035] The device of the presently disclosed embodiment is for this purpose a device designed to restrain tanks for housing cryogenic propellants with a capacity of a few metric tonnes without subjecting them to stresses that oppose their longitudinal or radial contraction/expansion.
[0036] More particularly, the disclosed embodiment proposes a device for supporting and holding a tank of cylindrical or conical overall shape and of main axis X in a vehicle such as an aircraft, which comprises a pair of first tank-retaining means for retaining the tank along an axis Z perpendicular to the main axis X at each of a first and of a second end of the tank, a second means for retaining the tank along an axis Y perpendicular to the main axis X and to the axis Z, at the first end of the tank and a third retaining means designed to retain the tank along the axis X and the axis Y and connected to the second end of the tank.
[0037] Advantageously, the tank supporting and holding device further comprises a second means for retaining along the axis Y at the first end of the tank so as to constitute a redundant safety retaining means.
[0038] The first means and the second means advantageously consist of link rods fixed to the tank by means of pins free to rotate and arranged in such a way as to allow the tank to expand or contract freely.
[0039] According to one particular aspect, the first end of the tank, the link rods define three fixing points distributed at the top and the two sides of the first end of the tank.
[0040] The first means advantageously comprise four link rods arranged symmetrically with respect to planes of symmetry ZY and ZX of the tank and oriented along the axis Z in order to react tank accelerations on the axis Z.
[0041] According to one particular aspect, the fixing points of said four link rods to the tank are located in the plane of symmetry XY of the tank.
[0042] The second retaining means advantageously consists of a link rod at the front of the tank, positioned in the plane XY and reacting forces along the axis Y transverse to the main axis X of the tank.
[0043] The link rod positioned in the plane XY, and the link rods orientated along the axis Z, are advantageously positioned in such a way as to allow the tank deformations along the axis X while at the same time allowing the tank some radial travel so as not to generate stress caused by the radial thermal deformations of the tank.
[0044] The fixing point of the link rod positioned in the plane XY on the tank is advantageously in the plane of symmetry XZ of the tank.
[0045] The link rods are advantageously positioned in such a way as to work tangentially to the skin of the tank.
[0046] The disclosed embodiment applies in particular to an aircraft comprising a tank and a tank supporting and holding device according to the disclosed embodiment, for which the main axis X is a horizontal axis parallel to the aircraft axis, or at a small angle to the aircraft axis, the axis Y is a horizontal axis transverse to the aircraft and the axis Z is a vertical axis, the first and second means being held on frames of the fuselage of the aircraft.
[0047] The tank is advantageously suspended from the first retaining means.
[0048] The first and second retaining means advantageously are link rods fixed by ball-joints to attachments of the tank and attachments on frames of the aircraft, or on shock-absorbing webs between frames.
[0049] The third retaining means advantageously comprises a vertical fixing rod fixed to a structure of the aircraft and pushed into a sliding joint surrounded by a spherical ball at the end of a skirt secured to the tank, for which the structure provides for the transmission of force from the rod to the fuselage of the aircraft, and for which the sliding joint reacts force along the axes X and Y while at the same time being entirely free to rotate and free to effect a translational movement about the rod along the vertical axis Z.
[0050] According to one particular aspect, the aircraft comprises a safety redundancy of the third retaining means which, according to one particular aspect, is achieved by a peg/clearance hole device situated between the skirt, between the vertical pin and the tank, and a support fixed to the fuselage so as to restrain the tank in X and in Y upon breakage of the vertical pin or of the skirt on the tank side.
[0051] The aircraft is advantageously a space aircraft and the tank is a cryogenic feed tank for a rocket engine of the space aircraft, the retaining means being configured to provide degrees of freedom suited to avoiding thermomechanical stresses under the effect of differential thermal deformations of the tank in the longitudinal and radial directions.
[0052] According to one advantageous aspect, the structure comprises a double flange.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] Other features and advantages of the disclosed embodiment will become apparent from reading the following description of one nonlimiting exemplary aspect of the disclosed embodiment accompanied by the drawings which depict:
[0054] FIG. 1 is one example of the fixing of a launcher tank of the prior art;
[0055] FIG. 2 is a three-quarters front perspective view of a tank with a supporting and holding device according to the disclosed embodiment;
[0056] FIG. 3 is a three-quarters rear perspective view of a tank with a supporting and holding device according to the disclosed embodiment;
[0057] FIGS. 4A and 4B are schematic views of the fixings at a first end of the tank according to two particular aspects of the disclosed embodiment;
[0058] FIG. 5 is a detail of a retaining means according to the disclosed embodiment;
[0059] FIG. 6 is a view in longitudinal section of a detail of a third retaining means with ball-joint of the disclosed embodiment;
[0060] FIGS. 7A and 7B are views of the retaining means of FIG. 6 in perspective and in an exploded view, respectively.
DETAILED DESCRIPTION
[0061] The disclosed embodiment relates to a device for supporting and holding a tank 100 as depicted in FIGS. 2 and 3 , of cylindrical or conical overall shape and of main axis X, a horizontal axis corresponding to the main axis of the aircraft according to the disclosed embodiment.
[0062] The device in general comprises a number of tank retaining means, these means being divided into three groups: first means intended to support the tank, one or more second means intended to restrain one end of the tank in a lateral direction perpendicular to the main axis X, and a third retaining means creating an anchor point anchoring the tank with respect to the fuselage of the aircraft.
[0063] The device thus comprises, in the first place, a pair of first means 2 a , 2 b , 2 c , 2 d of retaining the tank along an axis Z at each of a first 101 and of a second 102 end of the tank. In the example, the axis Z is a vertical axis, the first means supporting the tank in the fuselage of the aircraft.
[0064] The first pair of first means 2 a , 2 b is depicted in FIG. 2 and the second pair 2 c , 2 d is depicted in FIG. 3 . The first means 2 a , 2 b , 2 c , 2 d comprise four link rods 30 arranged symmetrically with respect to planes of symmetry ZY and ZX of the tank and oriented vertically in order to react accelerations of the tank along the vertical axis Z, the axis Y being a horizontal axis perpendicular to the axes X and Z.
[0065] One example of a link rod 30 that can be applied to the first means is depicted in FIG. 5 .
[0066] It comprises a body and two ball-joints 53 , 54 which are respectively connected to an attachment 103 of the tank via a pin 51 and to an attachment 11 via a pin 52 on a frame 1 of the aircraft.
[0067] The link rods are positioned in such a way as to work tangentially to the skin of the tank 100 so as to avoid any puncturing of the tank which would be highly detrimental to its integrity.
[0068] The supporting elements of the link rod type need to have both good tensile and compressive strength in the wide variety of loading scenarios that may be encountered. On the other hand, they must not offer resistance at right angles to their working axis.
[0069] The attachments 103 according to the example are made on hoops 104 at the periphery of the ends 101 , 102 of the tank.
[0070] Returning to FIGS. 2 and 3 , the fixing points of said four link rods 30 to the tank 100 are located in the plane of symmetry XY of the tank according to the orthonormal frame of reference 200 .
[0071] Still according to FIG. 2 , the device of the disclosed embodiment comprises, at the first end 101 of the tank, a second means 3 of retaining the tank along a horizontal axis Y perpendicular to the main axis.
[0072] The second retaining means 3 which will serve to prevent the tank from rotating about the axis Z and from moving in Y at its first end consists, according to the example, of a high link rod at the front of the tank 100 , positioned in the plane XY and reacting forces along the axis Y transverse to the main axis X of the tank 100 .
[0073] The high link rod positioned in the plane XY is oriented in such a way as to allow the tank to deform along the axis X while at the same time allowing the tank some radial travel so as not to generate stresses caused by the radial thermal deformations of the tank. Finally, the point of attachment of the high link rod to the tank is in the plane of symmetry XZ of the tank.
[0074] It should be noted that the first means comprising the first link rods prevent the tank from rotating about its axis.
[0075] From a functional standpoint, at the first end of the tank, the link rods 30 of the first and second support means define three fixing points distributed at the top and the two sides of the first end 101 of the tank as depicted in FIGS. 4A and 4B .
[0076] This collection of fixing points allows the front of the tank to move longitudinally along the axis X as it expands/contracts.
[0077] In order to perform a failure-tolerant or safety function (a failsafe function) in the event of failure, a second support means may also be added to create redundancy in the event of the high link rod or its fixing points breaking.
[0078] This means may either be a second high link rod 3 a as in FIG. 4A , or a low link rod 3 b as in FIG. 4B and will be positioned on the same side of the tank as the second means in the case of the example depicted.
[0079] As far as the first retaining means from which the tank is suspended are concerned, the presence of two pairs of means is intrinsically redundant because if one link rod breaks, the remaining three link rods are enough to retain the tank along the axis Z.
[0080] The first means are thus arranged symmetrically with respect to the planes of symmetry ZY and ZX of the tank and oriented vertically to react accelerations along the axis Z. To limit loading to a minimum, the fixing points at which the link rods are fixed to the tank are located in the plane of symmetry XY of the tank. The link rods comprise balls at each of their ends in the region of the attachment to the tank and in the region of the attachment to the bearing structure, to allow for differential thermal expansions. Their orientation prioritizes relative deformations in the longitudinal direction but also allows enough travel that stresses are not generated as a result of radial thermal deformations. These 4 link rods constitute an assembly that is tolerant of failure with regard to the reaction of forces along the axis Z.
[0081] The device is thus made up of a set of link rods provided with ball-joint fixings, in limited number, arranged in such a way that the setup is as isostatic as possible while at the same time affording redundancy in the transmission of force.
[0082] The device is supplemented at the second end of the tank by a third retaining means with ball-joint 4 about the vertical axis connected to the second end 102 of the tank.
[0083] This spherical ball-joint retaining means which alone reacts all of the force in the airplane direction is more particularly depicted in FIG. 6 .
[0084] This retaining means or device is intended to restrain the tank in a direction X along the main fore-aft axis of the aircraft and along the axis Y perpendicular to the axis X.
[0085] This means supplements the second means to restrain the tank laterally and creates an anchor point for the tank in the longitudinal direction X of the aircraft.
[0086] According to the example depicted and as will be explained hereinbelow, this retaining means is produced using a retaining device which has a degree of freedom to rotate about this axis X, a degree of freedom to effect translational movement along an axis Z perpendicular to the plane of the wing structure of the aircraft, and a degree of freedom to rotate about said axis Z.
[0087] This third retaining means constitutes a point on the tank that is fixed in terms of X with respect to the airplane whereas the first and second means are produced in such a way as to expand or contract with the tank.
[0088] The forces along the axis Y are reacted by the high link rod 3 positioned horizontally at the front and a rod 20 positioned at the bottom rear part of the tank.
[0089] Flight forces in the X direction are reacted at the third retaining means formed by a single attachment point consisting of the rod 20 positioned at the bottom rear part of the tank.
[0090] This attachment point is the only fixed point on the tank with respect to the longitudinal axis X so that the significant differential thermal expansions between the tank and the airplane structure are permitted at the other attachments without generating thermomechanical stresses on the tank or on the attachment points.
[0091] The third retaining means comprises the vertical rod 20 fixed to a structure 12 of the airplane and pushed into a sliding joint 21 surrounded by a spherical ball 22 at the end of a skirt 23 secured to the tank 100 .
[0092] The structure transmits force from the pin into the fuselage of the airplane and the vertical pin reacts force on the axes X and Y while being at the same time free to rotate and to effect a translational movement along Z between end stops.
[0093] The rod 20 opposes a translational movement of the tank along the axes X and Y, the retaining means on the other hand being supplemented by a ball-joint connection which connects the tank to the vertical rod in terms of translation but offers it three degrees of freedom for the three rotations thus decoupling the tank from this first retaining means in pitch, roll and yaw.
[0094] To summarize, the fixing rod 20 is pushed into a sliding joint 21 surrounded by a spherical ball 22 at the end of a skirt 23 secured to the tank 100 , the structure transmits force from the rod into the fuselage of the airplane and the sliding and ball-joint connection reacts force along the horizontal axes X and Y or in a plane parallel to the plane of the wing structure of the aircraft while at the same time having freedom to rotate and effect a translational movement about the rod 20 along the vertical axis Z perpendicular to the plane of the wing structure of the aircraft.
[0095] FIGS. 7A and 7B detail the articulated means depicted in FIG. 6 .
[0096] FIG. 7A depicts the positioning of the pin 20 in a bearing that forms a sliding joint 21 whereas in FIG. 6 , the sliding joint 21 depicted is rather a connection involving rolling balls. The bearing is inserted in the ring of spherical exterior profile 22 a of the ball-joint 22 .
[0097] FIG. 7B details one exemplary aspect of the spherical ball-joint comprising the ring with a spherical exterior profile 22 a housed in a way known per se in an outer cage 22 b with a spherical interior profile, here in the known form of a lower annulus and of an upper annulus. The outer cage 22 b in which the spherical ball-joint is mounted is received in a housing made in the skirt 23 secured to the tank.
[0098] In some way the tank may be considered to be attached to the rod 20 while at the same time being able to pivot in all directions about its point of attachment, the point of attachment furthermore being able to slide along the rod. The retaining device is thus designed to create a point of anchoring the tank to the aircraft, complementary retaining means here produced by the link rods of the first and second means keeping the tank aligned with the fuselage of the aircraft.
[0099] The link rods which are fixed to the tank and to the fuselage by means of pins free to rotate are arranged in such a way as to allow the tank to expand or contract freely.
[0100] The failsafe nature of this connection is guaranteed by safety redundancy of the third retaining means created by producing the rod 20 in the form of a double pin comprising an outer part and an inner part such that if the outer part of the pin should break, the inner part would still be able to react shear forces.
[0101] FIG. 7B is a perspective depiction of the double pin which comprises the internal rod 20 a and external tube 20 b which are concentric and pushed one inside the other.
[0102] Furthermore, a peg 24 enters, with clearance, a hole 25 situated on the skirt 23 , between the vertical rod 20 and the tank, the peg being inserted in a support 26 fixed to the fuselage so as to restrain the tank in X and Y in case the skirt 23 breaks on the tank side.
[0103] The structural structure 12 , which constitutes the support for the connection on the fuselage side and which may potentially be produced in the form of a box section, comprises two flanges 121 , 122 , each one capable of reacting all of the force of the rod 20 , thereby also contributing to the safety of the device.
[0104] On the airplane structure side, the solution requires few if any dedicated structural elements, the structure relying on frames 1 of the fuselage 10 .
[0105] Returning again to FIG. 5 , the link rods are attached to existing frames or between two frames on additional shock-absorbing webs or additional frame portions.
[0106] The ideal is of course to position the frames when designing the architecture of the airplane structure so that these frames coincide with the interfaces with the tanks, giving rise to a coherent airplane/tank structure design.
[0107] Note that this system offers a great deal of flexibility regarding the positioning of the tanks in the fuselage. The tanks are not for example constrained to being situated near a pressurized end wall or any other strong structure.
[0108] According to the configuration adopted, the retaining means have an optimal arrangement for a tank, the main loading scenarios of which are accelerations in the direction transverse to the tank and downwards and accelerations in the longitudinal direction of the tank. It is also possible to design the system with Z link rods operating in compression at least at one end of the tank. Nevertheless, this aspect is not as optimal.
[0109] According to the example, the first end of the tank is positioned at the front of the airplane and the second end at the rear and the relative positioning of the second means 3 and of the third means 4 , one at the top at the front, one at the bottom at the rear with respect to the airplane, is optimal for equalizing radial forces and limiting induced moments. However, the reverse configuration is nonetheless possible.
[0110] Like the vertical link rods, the high link rod of the second means is provided with ball-joints at its two ends and oriented in such a way as to prioritize relative deformations in the longitudinal direction while at the same time providing sufficient travel so that stresses are not generated as a result of the radial thermal deformations. For optimum behavior, the point at which this link rod is fixed to the tank needs to lie in the plane of symmetry XZ of the tank.
[0111] The collection of measures described hereinabove make it possible to limit the loadings both in the tank and in the airplane structure, and in the fixings themselves. The overall mass is thus itself optimized.
[0112] The arrangement, number and design of the attachments ensures a configuration which is safeguarded overall in the event of failure (a failsafe configuration).
[0113] Limiting the number of attachments, and the simplicity of the attachments, moreover makes for rapid and easy operations of incorporating the tanks into the fuselage or removing them for maintenance operations, even in the case of tank diameters close to the fuselage diameter. For this same reason, inspection is facilitated via a number of carefully positioned inspection hatches and can be carried out as often as necessary, for each flight if required.
[0114] The tank is notably a cryogenic tank supplying a rocket motor of the spaceplane, the retaining means being configured to provide degrees of freedom suited to avoiding thermomechanical stresses under the effect of differential thermal deformations in the longitudinal direction, shortening of the tank, and radially with respect to the tank, notably the striction of the tank.
[0115] The limited number of points of attachment between the cryogenic tank and the bearing structure, which is furthermore of small size, finally makes it possible to limit exchanges of heat between these two elements.
[0116] The device of the disclosed embodiment offers optimization of the overall mass across the entire tank, airplane structure and support assembly. This device also affords an appreciable reduction in time spent on maintenance and tank removal by reducing the number of interfaces with the tank to the bare minimum.
[0117] This device furthermore ensures that the tank fixings will not impose stresses on the tank as it expands and contracts as a function of its temperature.
[0118] The disclosed embodiment is not restricted to the example depicted and notably the orientation of the link rods can vary according to the orientation of the main design forces specific to the craft in question and to the flight profile thereof. | The present invention relates to a device for mounting and supporting a generally cylindrical or tapered tank, having a main axis X, that includes a pair of first means for retaining the tank along a vertical axis Z on each of a first and second end of the tank, a second means for retaining the tank along a horizontal axis Y, perpendicular to the main axis, on the first end of the tank, and a third means for retaining in a ball-and-socket joint, the means being located around the vertical axis and connected to the second end of the tank. | 5 |
TECHNICAL FIELD
[0001] The present invention relates to high temperature fuel cells having a solid-oxide electrolytic layer separating an anode layer from a cathode layer; more particularly, to high temperature fuel cell systems comprising a plurality of individual fuel cells in a stack wherein fuel is provided by an associated catalytic hydrocarbon reformer; and most particularly, to such a fuel cell system wherein steady-state reforming is substantially endothermic and wherein a high percentage of the anode tail gas is recycled through the reformer to improve system efficiency.
BACKGROUND OF THE INVENTION
[0002] Fuel cells which generate electric current by controllably combining elemental hydrogen and oxygen are well known. In one form of such a fuel cell, an anodic layer and a cathodic layer are separated by a non-permeable electrolyte formed of a ceramic solid oxide. Such a fuel cell is known in the art as a “solid-oxide fuel cell” (SOFC). It is further known to combine a plurality of such fuel cells into a manifolded structure referred to in the art as a “fuel cell stack” and to provide a partially-oxidized “reformate” fuel (“syngas”) to the stack from a hydrocarbon catalytic reformer.
[0003] Prior art catalytic partial-oxidizing (POX) reformers typically are operated exothermically by using intake air to partially oxidize hydrocarbon fuel as may be represented by the following equation for a hydrocarbon and air,
C 7 H 12 +3.5(O 2 +3.77N 2 )→6H 2 +7CO+13.22N 2 +heat (Eq. 1)
wherein the oxygen/carbon atomic ratio is 1.0, and the resulting reformate temperature is in the range of about 1000° C. Prior art reformers typically are operated slightly fuel-lean of stoichiometric to prevent coking of the anodes from non-reformed hydrocarbon decomposition within the fuel cell stack. Thus some full combustion of hydrocarbon and reformate occurs within the reformer in addition to, and in competition with, the electrochemical combustion of the fuel cell process. Such full combustion is wasteful of fuel and creates additional heat which must be removed from the reformate and/or stack, typically by passing a superabundance of cooling air through the cathode side of the stack.
[0004] It is known to produce a reformate containing hydrogen and carbon monoxide by endothermic steam reforming (SR) of hydrocarbon in the presence of water which may be represented by the following equation,
C 7 H 12 +7H 2 O+heat→13H 2 +7CO (Eq. 2)
wherein the oxygen/carbon atomic ratio is still 1.0 and the reformate temperature is still about 1000° C. The disadvantages of this process for providing reformate for operating a fuel cell are 1) a continuous water supply must be provided; 2) heat must be provided, typically in the form of burned fuel, thus reducing the efficiency of the system; and 3) the reforming temperature is hard on the reformer materials and catalyst.
[0005] High temperature fuel cells inherently produce a combination of direct current electricity, waste heat, and syngas. The syngas, as used herein, is a mixture of unburned reformate, including hydrogen, carbon monoxide, and nitrogen, as well as combustion products such as carbon dioxide and water. In some prior art fuel cell systems, the syngas is burned in an afterburner, and the heat of combustion is partially recovered by heat exchange to the reformer, to the cathode inlet air, or both.
[0006] In accordance with the invention disclosed in the co-pending and commonly owned patent application Ser. No. ______ entitled “Apparatus and Method for Operation of a High Temperature Fuel Cell System Using Recycled Anode Exhaust”, a relatively small percentage, typically between 5% and 30%, of the anode syngas may be recycled into the reformer a) to increase fuel efficiency by endothermic reforming of water and carbon dioxide in the syngas in accordance with Equation 2 above (thus combining POX and SR reforming); b) to add excess water to the reformate to increase protection against anode coking; and c) to provide another opportunity for anode consumption of residual hydrogen. In such systems, and especially when using heavy fuels such as gasoline and diesel, the reformer typically is operated at a high temperature (which may even exceed the stack temperature) to provide the energy necessary for endothermic reforming. However, such high temperatures may be deleterious to the reformer over a period of time, and tend to lower system efficiency. From a durability point of view, it is desirable to be able to operate a reformer at the lowest temperature possible (without being in an operating region of carbon formation).
[0007] In a fuel cell stack, the reformate consumed is converted into approximately equal amounts of heat and electricity. The stack is cooled primarily by the flow of gases through it. Even with a modest amount of recycle flow added to the reformate, the total reformate massflow is relatively small, on the order of one-tenth the massflow of the cathode air, so the majority of cooling is done by cathode air. As previously noted, in endothermic reforming of recycled syngas with modest recycle rates, the reformate produced cannot be cooled much below stack temperature without risk of carbon nucleation. Therefore, in order to keep a reasonable temperature gradient in the stack between the inlet and outlet of the cathode, a very high cathode air massflow is required, being many times the amount required for the electrochemistry of the stack. This creates an added energy parasitic to the stack in the form of a very large air blower, and also tends to make the size of the cathode heat exchanger much larger than would otherwise be necessary.
[0008] What is needed in the art is a means for reducing the superabundance of air required in operation of a high temperature fuel cell system.
[0009] What is further needed is a means for improving the efficiency of reformer and stack processes while operating the reformer at a temperature below the stack temperature; for minimizing the size and weight of the heat exchangers; and for retaining most or all of the latent heat value of the anode tail gas for downstream processes.
[0010] It is a principal object of the present invention to provide high efficiency operation of a high temperature fuel cell system with reduced total air flow and endothermic reforming.
BRIEF DESCRIPTION OF THE INVENTION
[0011] Briefly described, a method for operating a hydrocarbon catalytic reformer and close-coupled fuel cell system in accordance with the invention comprises recycling a high percentage of anode syngas into the reformer, preferably in excess of 60%, and as high as 95%. Although air must be supplied to the reformer at start-up, after the system reaches equilibrium operating conditions some or all of the oxygen required for reforming of hydrocarbon fuel is derived from endothermically reformed water and carbon dioxide in the syngas. The recycle rate is considerably higher than the minimum required to supply these oxidants to the fuel. However, the high atomic oxygen/carbon ratio allows lower reforming temperature, in the range of about 650° C. to 750° C., without carbon formation, even with heavy fuels such as gasoline, diesel, or jet fuel. This temperature is sufficiently lower than the stack exit temperature of about 800° C. to 880° C. or higher that most or all of the required endotherm can be provided by the sensible heat of the recycled syngas.
[0012] The high stack exit temperature is achieved by having approximately equal cooling from the anode and cathode sides of the stack. The cathode air flow is significantly reduced over that of the prior art. Overheating of elements within the stack is prevented by configuring the approximately equal anode and cathode gas flows in opposite directions through their respective gas spaces (“counterflow”), such that entering reformate cools the exiting region of the cathode and exiting cathode air, and entering cathode air cools the exiting region of the anode and the exiting syngas. This is a significant improvement over the prior art cross-flow or co-flow arrangements which inherently have an area of the stack and gas seals running undesirably close to, or even above, the syngas exit temperature.
[0013] Using a 90% syngas recycle in accordance with the invention, system fuel efficiencies greater than 50% may be achieved, as well as increased power density in the fuel cell stack, improved stack cooling, lower parasitic losses in air supply, more efficient reforming, and reduced cathode air and reformer heat exchanger sizes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will now be described, by way of example, with reference to the accompanying drawing, in which FIG. 1 is a schematic drawing of a high temperature fuel cell system in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring to FIG. 1 , a high temperature fuel cell system 10 as may be suited to use as an auxiliary power unit (APU) in a vehicle 11 includes components known in the art of solid-oxide or molten carbonate fuel cell systems. FIG. 1 is not a comprehensive diagram of all components required for operation but includes only those components novelly formed and/or arranged in accordance with the apparatus and method of the invention. Missing components will be readily inferred by those of ordinary skill in the art.
[0016] A hydrocarbon catalytic reformer 12 includes a heat exchanger 14 , preferably formed integrally therewith. A fuel cell stack 16 comprises preferably a plurality of individual fuel cell elements 17 connected electrically in series as is known in the art. Stack 16 includes passageways for passage of reformate across the anode surfaces of stack anodes 19 , the passageways being shown collectively and schematically as passageway 18 . Stack 16 also includes passageways for passage of air across the cathode surfaces of the stack cathodes 21 , the passageways being shown collectively and schematically as passageway 20 . Preferably, passageways 18 and 20 are arranged within stack 16 such that reformate flows across the anode surfaces in a direction different from the direction of air flow across the cathode surfaces. Preferably, the reformate flow and air flow directions 19 , 21 are directly opposed (counterflow) instead of crossing (crossflow), as is well known in the prior art, or flowing in the same direction (coflow). A cathode air heat exchanger 22 includes an intake air side 24 and an exhaust air side 26 . A high temperature recycle pump 28 is provided for recycling a portion of the anode tail gas into an inlet of the reformer, and for exporting syngas to an external process 47 . Syngas may also be used as a fuel to trim temperatures in the reformer and cathode air heating function inside the system (not shown).
[0017] Endothermic reforming with high percentage syngas recycle may be represented by the following equation,
C 7 H 12 +9H 2 O+10.5CO 2 +heat→10H 2 +10CO+5H 2 O+7.5CO 2 (Eq. 3)
wherein the oxygen/carbon ratio is 1.715, and the reformate temperature is about 750° C. Thus 4/9 of the hydrogen consumed to produce water in the electrochemical process of the fuel cell stack is recovered by endothermic reforming and is used over again, thus greatly increasing the hydrocarbon fuel efficiency of the system. Further, the energy required for the water reforming is derived from the “waste” energy in the anode syngas which in prior art high temperature fuel cells is discarded in the superabundance of cathode cooling air.
[0018] In operation, fuel is controllably supplied from a source (not shown) via line 30 to an inlet of reformer 12 , as is known in the art. Fuel may comprise any conventional or alternative fuel as is known in the art, for example, gasoline, diesel, jet fuel, kerosene, propane, natural gas, carbon, biodiesel, ethanol, and methanol. Air is supplied from a source (not shown), such as a blower or other air pump, via line 32 to intake air side 24 of heat exchanger 22 and thence via line 34 to cathode passageway 20 . At start-up, heated air is also supplied from heat exchanger 22 via line 36 to an inlet on reformer 12 to provide oxygen for reformer start-up in known fashion. At a time after start-up when such air is no longer needed, or may be reduced in volume in accordance with the invention, the air flow to the reformer may be controllably modulated by an air valve 38 .
[0019] Reformate is supplied via line 40 from reformer 12 to anode passageway 18 . Anode tail gas is exhausted from stack 16 via line 42 and is preferably assisted by inline pump 28 . Syngas is exhausted from pump 28 via line 44 , and a portion of the exhausted syngas may be recycled to an inlet of reformer 12 via line 46 . Preferably, the recycled portion in line 46 is between about 50% and about 95% of the total syngas flow in line 44 .
[0020] Heated cathode air is exhausted from cathode passageway 20 via line 48 and is provided to reformer heat exchanger 14 wherein heat is abstracted to assist in reforming processes within reformer 12 . Spent air is exhausted from heat exchanger 14 via line 50 and is passed through exhaust side 26 of heat exchanger 22 wherein heat is abstracted by intake air in inlet side 24 . Cooled air is discharged to atmosphere via line 52 .
[0021] In an exemplary method of operation of 5 kW SOFC APU based on system 10 in accordance with the invention, syngas flow being recycled to reformer 12 via line 46 is at least about 75%, and preferably between about 90% and 95%, of the total syngas amount flowing through line 44 . This is in contrast with prior art recycle flows of about 25% or less. Fuel, recycle syngas, and oxidant flows to reformer 12 are adjusted in known fashion such that reformate flow in line 40 to stack 16 is about 6.4 grams/second at a temperature of about 650° C. Air flow through line 34 to stack 16 is about 8.0 grams/second at a temperature of about 680° C. Stack 16 is sized such that the anode tailgas is exhausted from passageway 18 at a temperature of about 840° C. and air is exhausted from passageway 20 at a temperature of about 840° C.
[0022] Under these or similar steady-state operating conditions, little or no air must be provided to reformer 12 via line 36 and valve 38 . Sufficient heat is provided to the reformer from the sensible heat of the recycled tail gas to permit endothermic reforming of the input fuel and the water and carbon dioxide in the syngas. This requires that the in-line pump 28 is capable of pumping high temperature gas and that line 44 is designed to avoid heat losses to lower temperature zones of the system.
[0023] Note that the reformer is thus permitted to operate at a significantly lower temperature (reformate temperature approximately 100 to 200° C. less than stack temperature) than in the prior art exothermic reforming (reformate temperature >800° C. to 1000° C.), which is highly beneficial to longevity of the reformer catalyst.
[0024] Note also that most, if not all, of the oxygen required for endothermic reforming is obtained from the water and carbon dioxide in the recycled anode tailgas. The oxygen contained in the water and carbon dioxide has come from cathode oxygen that has migrated through the electrolyte for reaction at the anode in the stack.
[0025] Note also that the stack is permitted to operate at a higher average temperature due to improved internal heat control from counterflow reformate/air pathways. This allows the active area of the electrolyte to have a flatter temperature profile closer to the thermal limits of the stack seals and interconnects, thus improving power density and system efficiency.
[0026] Note also that the improved stack cooling and resulting higher stack temperature provides a hotter cathode air effluent which allows heat exchangers 14 , 26 to be downsized.
[0027] Note also that the high recycle rate of syngas allows the cooler reformate to participate more fully in temperature control of the stack and thus requires substantially less cathode airflow, thus permitting the air pump to be downsized.
[0028] While the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims. | Apparatus and method for operating a fuel cell system including a hydrocarbon catalytic reformer and close-coupled fuel cell stack by recycling anode syngas into the reformer in a range between 60% and 95% of the total syngas. At equilibrium conditions, oxygen required for reforming of hydrocarbon fuel is derived from endothermically reformed water and carbon dioxide in the syngas. Reforming temperature is between about 650° C. to 750° C. The stack exit temperature is about 800° C. to 880° C. such that the required endotherm can be provided by the sensible heat of the recycled syngas. The stack has approximately equal anode and cathode gas flows in opposite directions, resulting in cooling from both the anodes and cathodes. | 8 |
[0001] CROSS-REFERENCE TO RELATED APPLICATION
[0002] The present application claims the benefit of the filing date of copending provisional application serial no. 60/127,106 filed Mar. 31, 1999.
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a method of performing a downhole test of a subterranean formation.
[0004] In a typical well test known as a drill stem test, a drill string is installed in a well with specialized drill stem test equipment interconnected in the drill string. The purpose of the test is generally to evaluate the potential profitability of completing a particular formation or other zone of interest, and thereby producing hydrocarbons from the formation. Of course, if it is desired to inject fluid into the formation, then the purpose of the test may be to determine the feasibility of such an injection program.
[0005] In a typical drill stem test, fluids are flowed from the formation, through the drill string and to the earth's surface at various flow rates, and the drill string may be closed to flow therethrough at least once during the test. Unfortunately, the formation fluids have in the past been exhausted to the atmosphere during the test, or otherwise discharged to the environment, many times with hydrocarbons therein being burned off in a flare. It will be readily appreciated that this procedure presents not only environmental hazards, but safety hazards as well.
[0006] Therefore, it would be very advantageous to provide a method whereby a formation may be tested, without discharging hydrocarbons or other formation fluids to the environment, or without flowing the formation fluids to the earth's surface. It would also be advantageous to provide apparatus for use in performing the method.
SUMMARY OF THE INVENTION
[0007] In carrying out the principles of the present invention, in accordance with an embodiment thereof, a method is provided in which a formation test is performed downhole, without flowing formation fluids to the earth's surface, or without discharging the fluids to the environment. Also provided are associated apparatus for use in performing the method.
[0008] In one aspect of the present invention, a method includes steps wherein a formation is perforated, and fluids from the formation are flowed into a large surge chamber associated with a tubular string installed in the well. Of course, if the well is uncased, the perforation step is unnecessary. The surge chamber may be a portion of the tubular string. Valves are provided above and below the surge chamber, so that the formation fluids may be flowed, pumped or reinjected back into the formation after the test, or the fluids may be circulated (or reverse circulated) to the earth's surface for analysis.
[0009] In another aspect of the present invention, a method includes steps wherein fluids from a first formation are flowed into a tubular string installed in the well, and the fluids are then disposed of by injecting the fluids into a second formation. The disposal operation may be performed by alternately applying fluid pressure to the tubular string, by operating a pump in the tubular string, by taking advantage of a pressure differential between the formations, or by other means. A sample of the formation fluid may conveniently be brought to the earth's surface for analysis by utilizing apparatus provided by the present invention.
[0010] In yet another aspect of the present invention, a method includes steps wherein fluids are flowed from a first formation and into a second formation utilizing an apparatus which may be conveyed into a tubular string positioned in the well. The apparatus may include a pump which may be driven by fluid flow through a fluid conduit, such as coiled tubing, attached to the apparatus. The apparatus may also include sample chambers therein for retrieving samples of the formation fluids.
[0011] In each of the above methods, the apparatus associated therewith may include various fluid property sensors, fluid and solid identification sensors, flow control devices, instrumentation, data communication devices, samplers, etc., for use in analyzing the test progress, for analyzing the fluids and/or solid matter flowed from the formation, for retrieval of stored test data, for real time analysis and/or transmission of test data, etc.
[0012] These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a schematic cross-sectional view of a well wherein a first method and apparatus embodying principles of the present invention are utilized for testing a formation;
[0014] [0014]FIG. 2 is a schematic cross-sectional view of a well wherein a second method and apparatus embodying principles of the present invention are utilized for testing a formation;
[0015] [0015]FIG. 3 is an enlarged scale schematic cross-sectional view of a device which may be used in the second method;
[0016] [0016]FIG. 4 is a schematic cross-sectional view of a well wherein a third method and apparatus embodying principles of the present invention are utilized for testing a formation; and
[0017] [0017]FIG. 5 is an enlarged scale schematic cross-sectional view of a device which may be used in the third method.
DETAILED DESCRIPTION
[0018] Representatively illustrated in FIG. 1 is a method 10 which embodies principles of the present invention. In the following description of the method 10 and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., without departing from the principles of the present invention.
[0019] In the method 10 as representatively depicted in FIG. 1, a wellbore 12 has been drilled intersecting a formation or zone of interest 14 , and the wellbore has been lined with casing 16 and cement 17 . In the further description of the method 10 below, the wellbore 12 is referred to as the interior of the casing 16 , but it is to be clearly understood that, with appropriate modification in a manner well understood by those skilled in the art, a method incorporating principles of the present invention may be performed in an uncased wellbore, and in that situation the wellbore would more appropriately refer to the uncased bore of the well.
[0020] A tubular string 18 is conveyed into the wellbore 12 . The string 18 may consist mainly of drill pipe, or other segmented tubular members, or it may be substantially unsegmented, such as coiled tubing. At a lower end of the string 18 , a formation test assembly 20 is interconnected in the string.
[0021] The assembly 20 includes the following items of equipment, in order beginning at the bottom of the assembly as representatively depicted in FIG. 1: one or more generally tubular waste chambers 22 , an optional packer 24 , one or more perforating guns 26 , a firing head 28 , a circulating valve 30 , a packer 32 , a circulating valve 34 , a gauge carrier 36 with associated gauges 38 , a tester valve 40 , a tubular surge chamber 42 , a tester valve 44 , a data access sub 46 , a safety circulation valve 48 , and a slip joint 50 . Note that several of these listed items of equipment are optional in the method 10 , other items of equipment may be substituted for some of the listed items of equipment, and/or additional items of equipment may be utilized in the method and, therefore, the assembly 20 depicted in FIG. 1 is to be considered as merely representative of an assembly which may be used in a method incorporating principles of the present invention, and not as an assembly which must necessarily be used in such method.
[0022] The waste chambers 22 may be comprised of hollow tubular members, for example, empty perforating guns (i.e., with no perforating charges therein). The waste chambers 22 are used in the method 10 to collect waste from the wellbore 12 immediately after the perforating gun 26 is fired to perforate the formation 14 . This waste may include perforating debris, wellbore fluids, formation fluids, formation sand, etc. Additionally, the pressure reduction in the wellbore 12 created when the waste chambers 22 are opened to the wellbore may assist in cleaning perforations 52 created by the perforating gun 26 , thereby enhancing fluid flow from the formation 14 during the test. In general, the waste chambers 22 are utilized to collect waste from the wellbore 12 and perforations 52 prior to performing the actual formation test, but other purposes may be served by the waste chambers, such as drawing unwanted fluids out of the formation 14 , for example, fluids injected therein during the well drilling process.
[0023] The packer 24 may be used to straddle the formation 14 if another formation therebelow is open to the wellbore 12 , a large rathole exists below the formation, or if it is desired to inject fluids flowed from the formation 14 into another fluid disposal formation as described in more detail below. The packer 24 is shown unset in FIG. 1 as an indication that its use is not necessary in the method 10 , but it could be included in the string 18 , if desired.
[0024] The perforating gun 26 and associated firing head 28 may be any conventional means of forming an opening from the wellbore 12 to the formation 14 . Of course, as described above, the well may be uncased at its intersection with the formation 14 . Alternatively, the formation 14 may be perforated before the assembly 20 is conveyed into the well, the formation may be perforated by conveying a perforating gun through the assembly after the assembly is conveyed into the well, etc.
[0025] The circulating valve 30 is used to selectively permit fluid communication between the wellbore 12 and the interior of the assembly 20 below the packer 32 , so that formation fluids may be drawn into the interior of the assembly above the packer. The circulating valve 30 may include openable ports 54 for permitting fluid flow therethrough after the perforating gun 26 has fired and waste has been collected in the waste chambers 22 .
[0026] The packer 32 isolates an annulus 56 above the packer formed between the string 18 and the wellbore 12 from the wellbore below the packer. As depicted in FIG. 1, the packer 32 is set in the wellbore 12 when the perforating gun 26 is positioned opposite the formation 14 , and before the gun is fired. The circulating valve 34 may be interconnected above the packer 32 to permit circulation of fluid through the assembly 20 above the packer, if desired.
[0027] The gauge carrier 36 and associated gauges 38 are used to collect test data, such as pressure, temperature, etc., during the formation test. It is to be clearly understood that the gauge carrier 36 is merely representative of a variety of means which may be used to collect such data. For example, pressure and/or temperature gauges may be included in the surge chamber 42 and/or the waste chambers 22 . Additionally, note that the gauges 38 may acquire data from the interior of the assembly 20 and/or from the annulus 56 above and/or below the packer 32 . Preferably, one or more of the gauges 38 , or otherwise positioned gauges, records fluid pressure and temperature in the annulus 56 below the packer 32 , and between the packers 24 , 32 if the packer 24 is used, substantially continuously during the formation test.
[0028] The tester valve 40 selectively permits fluid flow axially therethrough and/or laterally through a sidewall thereof. For example, the tester valve 40 may be an Omni™ valve, available from Halliburton Energy Services, Inc., in which case the valve may include a sliding sleeve valve 58 and closeable circulating ports 60 . The valve 58 selectively permits and prevents fluid flow axially through the assembly 20 , and the ports 60 selectively permit and prevent fluid communication between the interior of the surge chamber 42 and the annulus 56 . Other valves, and other types of valves, may be used in place of the representatively illustrated valve 40 , without departing from the principles of the present invention.
[0029] The surge chamber 42 comprises one or more generally hollow tubular members, and may consist mainly of sections of drill pipe, or other conventional tubular goods, or may be purpose-built for use in the method 10 . It is contemplated that the interior of the surge chamber 42 may have a relatively large volume, such as approximately 20 barrels, so that, during the formation test, a substantial volume of fluid may be flowed from the formation 14 into the chamber, a sufficiently low initial drawdown pressure may be achieved during the test, etc. When conveyed into the well, the interior of the surge chamber 42 may be at atmospheric pressure, or it may be at another pressure, if desired.
[0030] One or more sensors, such as sensor 62 , may be included with the chamber 42 , in order to acquire data, such as fluid property data (e.g., pressure, temperature, resistivity, viscosity, density, flow rate, etc.) and/or fluid identification data (e.g., by using nuclear magnetic resonance sensors available from Numar, Inc.). The sensor 62 may be in data communication with the data access sub 46 , or another remote location, by any data transmission means, for example, a line 64 extending external or internal relative to the assembly 20 , acoustic data transmission, electromagnetic data transmission, optical data transmission, etc.
[0031] The valve 44 may be similar to the valve 40 described above, or it may be another type of valve. As representatively depicted in FIG. 1, the valve 44 includes a ball valve 66 and closeable circulating ports 68 . The ball valve 66 selectively permits and prevents fluid flow axially through the assembly 20 , and the ports 68 selectively permit and prevent fluid communication between the interior of the assembly 20 above the surge chamber 42 and the annulus 56 . Other valves, and other types of valves, may be used in place of the representatively illustrated valve 44 , without departing from the principles of the present invention.
[0032] The data access sub 46 is representatively depicted as being of the type wherein such access is provided by conveying a wireline tool 70 therein in order to acquire the data transmitted from the sensor 62 . For example, the data access sub 46 may be a conventional wet connect sub. Such data access may be utilized to retrieve stored data and/or to provide real time access to data during the formation test. Note that a variety of other means may be utilized for accessing data acquired downhole in the method 10 , for example, the data may be transmitted directly to a remote location, other types of tools and data access subs may be utilized, etc.
[0033] The safety circulation valve 48 may be similar to the valves 40 , 44 described above in that it may selectively permit and prevent fluid flow axially therethrough and through a sidewall thereof. However, preferably the valve 48 is of the type which is used only when a well control emergency occurs. In that instance, a ball valve 72 thereof (which is shown in its typical open position in FIG. 1) would be closed to prevent any possibility of formation fluids flowing further to the earth's surface, and circulation ports 74 would be opened to permit kill weight fluid to be circulated through the string 18 .
[0034] The slip joint 50 is utilized in the method 10 to aid in positioning the assembly 20 in the well. For example, if the string 18 is to be landed in a subsea wellhead, the slip joint 50 may be useful in spacing out the assembly 20 relative to the formation 14 prior to setting the packer 32 .
[0035] In the method 10 , the perforating guns 26 are positioned opposite the formation 14 and the packer 32 is set. If it is desired to isolate the formation 14 from the wellbore 12 below the formation, the optional packer 24 may be included in the string 18 and set so that the packers 32 , 24 straddle the formation. The formation 14 is perforated by firing the gun 26 , and the waste chambers 22 are immediately and automatically opened to the wellbore 12 upon such gun firing. For example, the waste chambers 22 may be in fluid communication with the interior of the perforating gun 26 , so that when the gun is fired, flow paths are provided by the detonated perforating charges through the gun sidewall. Of course, other means of providing such fluid communication may be provided, such as by a pressure operated device, a detonation operated device, etc., without departing from the principles of the present invention.
[0036] At this point, the ports 54 may or may not be open, as desired, but preferably the ports are open when the gun 26 is fired. If not previously opened, the ports 54 are opened after the gun 26 is fired. This permits flow of fluids from the formation 14 into the interior of the assembly 20 above the packer 32 .
[0037] When it is desired to perform the formation test, the tester valve 40 is opened by opening the valve 58 , thereby permitting the formation fluids to flow into the surge chamber 42 and achieving a drawdown on the formation 14 . The gauges 38 and sensor 62 acquire data indicative of the test, which, as described above, may be retrieved later or evaluated simultaneously with performance of the test. One or more conventional fluid samplers 76 may be positioned within, or otherwise in communication with, the chamber 42 for collection of one or more samples of the formation fluid. One or more of the fluid samplers 76 may also be positioned within, or otherwise in communication with, the waste chambers 22 .
[0038] After the test, the valve 66 is opened and the ports 60 are opened, and the formation fluids in the surge chamber 42 are reverse circulated out of the chamber. Other circulation paths, such as the circulating valve 34 , may also be used. Alternatively, fluid pressure may be applied to the string 18 at the earth's surface before unsetting the packer 32 , and with valves 58 , 66 open, to flow the formation fluids back into the formation 14 . As another alternative, the assembly 20 may be repositioned in the well, so that the packers 24 , 32 straddle another formation intersected by the well, and the formation fluids may be flowed into this other formation. Thus, it is not necessary in the method 10 for formation fluids to be conveyed to the earth's surface unless desired, such as in the sampler 76 , or by reverse circulating the formation fluids to the earth's surface.
[0039] Referring additionally now to FIG. 2, another method 80 embodying principles of the present invention is representatively depicted. In the method 80 , formation fluids are transferred from a formation 82 from which they originate, into another formation 84 for disposal, without it being necessary to flow the fluids to the earth's surface during a formation test, although the fluids may be conveyed to the earth's surface if desired. As depicted in FIG. 2, the disposal formation 84 is located uphole from the tested formation 82 , but it is to be clearly understood that these relative positionings could be reversed with appropriate changes to the apparatus and method described below, without departing from the principles of the present invention.
[0040] A formation test assembly 86 is conveyed into the well interconnected in a tubular string 87 at a lower end thereof. The assembly 86 includes the following, listed beginning at the bottom of the assembly: the waste chambers 22 , the packer 24 , the gun 26 , the firing head 28 , the circulating valve 30 , the packer 32 , the circulating valve 34 , the gauge carrier 36 , a variable or fixed choke 88 , a check valve 90 , the tester valve 40 , a packer 92 , an optional pump 94 , a disposal sub 96 , a packer 98 , a circulating valve 100 , the data access sub 46 , and the tester valve 44 . Note that several of these listed items of equipment are optional in the method 80 , other items of equipment may be substituted for some of the listed items of equipment, and/or additional items of equipment may be utilized in the method and, therefore, the assembly 86 depicted in FIG. 2 is to be considered as merely representative of an assembly which may be used in a method incorporating principles of the present invention, and not as an assembly which must necessarily be used in such method. For example, the valve 40 , check valve 90 and choke 88 are shown as examples of flow control devices which may be installed in the assembly 86 between the formations 82 , 84 , and other flow control devices, or other types of flow control devices, may be utilized in the method 80 , in keeping with the principles of the present invention. As another example, the pump 94 may be used, if desired, to pump fluid from the test formation 82 , through the assembly 86 and into the disposal formation 84 , but use of the pump 94 is not necessary in the method 80 . Additionally, many of the items of equipment in the assembly 86 are shown as being the same as respective items of equipment used in the method 10 described above, but this is not necessarily the case.
[0041] When the assembly 86 is conveyed into the well, the disposal formation 84 may have already been perforated, or the formation may be perforated by providing one or more additional perforating guns in the assembly, if desired. For example, additional perforating guns could be provided below the waste chambers 22 in the assembly 86 .
[0042] The assembly 86 is positioned in the well with the gun 26 opposite the test formation 82 , the packers 24 , 32 , 92 , 98 are set, the circulating valve 30 is opened, if desired, if not already open, and the gun 26 is fired to perforate the formation. At this point, with the test formation 82 perforated, waste is immediately received into the waste chambers 22 as described above for the method 10 . The circulating valve 30 is opened, if not done previously, and the test formation is thereby placed in fluid communication with the interior of the assembly 86 .
[0043] Preferably, when the assembly 86 is positioned in the well as shown in FIG. 2, a relatively low density fluid (liquid, gas (including air, at atmospheric or greater or lower pressure) and/or combinations of liquids and gases, etc.) is contained in the string 87 above the upper valve 44 . This creates a low hydrostatic pressure in the string 87 relative to fluid pressure in the test formation 82 , which pressure differential is used to draw fluids from the test formation into the assembly 86 as described more fully below. Note that the fluid preferably has a density which will create a pressure differential from the formation 82 to the interior of the assembly at the ports 54 when the valves 58 , 66 are open. However, it is to be clearly understood that other methods and means of drawing formation fluids into the assembly 86 may be utilized, without departing from the principles of the present invention. For example, the low density fluid could be circulated into the string 87 after positioning it in the well by opening the ports 68 , nitrogen could be used to displace fluid out of the string, a pump 94 could be used to pump fluid from the test formation 82 into the string, a difference in formation pressure between the two formations 82 , 84 could be used to induce flow from the higher pressure formation to the lower pressure formation, etc.
[0044] After perforating the test formation 82 , fluids are flowed into the assembly 86 via the circulation valve 30 as described above, by opening the valves 58 , 66 . Preferably, a sufficiently large volume of fluid is initially flowed out of the test formation 82 , so that undesired fluids, such as drilling fluid, etc., in the formation are withdrawn from the formation. When one or more sensors, such as a resistivity or other fluid property or fluid identification sensor 102 , indicates that representative desired formation fluid is flowing into the assembly 86 , the lower valve 58 is closed. Note that the sensor 102 may be of the type which is utilized to indicate the presence and/or identity of solid matter in the formation fluid flowed into the assembly 86 .
[0045] Pressure may then be applied to the string 87 at the earth's surface to flow the undesired fluid out through check valves 104 and into the disposal formation 84 . The lower valve 58 may then be opened again to flow further fluid from the test formation 82 into the assembly 86 . This process may be repeated as many times as desired to flow substantially any volume of fluid from the formation 82 into the assembly 86 , and then into the disposal formation 84 .
[0046] Data acquired by the gauges 38 and/or sensors 102 while fluid is flowing from the formation 82 through the assembly 86 (when the valves 58 , 66 are open), and while the formation 82 is shut in (when the valve 58 is closed) may be analyzed after or during the test to determine characteristics of the formation 82 . Of course, gauges and sensors of any type may be positioned in other portions of the assembly 86 , such as in the waste chambers 22 , between the valves 58 , 66 , etc. For example, pressure and temperature sensors and/or gauges may be positioned between the valves 58 , 66 , which would enable the acquisition of data useful for injection testing of the disposal zone 84 , during the time the lower valve 58 is closed and fluid is flowed from the assembly 86 outward into the formation 84 .
[0047] It will be readily appreciated that, in this fluid flowing process as described above, the valve 58 is used to permit flow upwardly therethrough, and then the valve is closed when pressure is applied to the string 87 to dispose of the fluid. Thus, the valve 58 could be replaced by the check valve 90 , or the check valve may be supplied in addition to the valve as depicted in FIG. 2.
[0048] If a difference in formation pressure between the formations 82 , 84 is used to flow fluid from the formation 82 into the assembly 86 , then a variable choke 88 may be used to regulate this fluid flow. Of course, the variable choke 88 could be provided in addition to other flow control devices, such as the valve 58 and check valve 90 , without departing from the principles of the present invention.
[0049] If a pump 94 is used to draw fluid into the assembly 86 , no flow control devices may be needed between the disposal formation 84 and the test formation 82 , the same or similar flow control devices depicted in FIG. 2 may be used, or other flow control devices may be used. Note that, to dispose of fluid drawn into the assembly 86 , the pump 94 is operated with the valve 66 closed.
[0050] In a similar manner, the check valves 104 of the disposal sub 96 may be replaced with other flow control devices, other types of flow control devices, etc.
[0051] To provide separation between the low density fluid in the string 87 and the fluid drawn into the assembly 86 from the test formation 82 , a fluid separation device or plug 106 which may be reciprocated within the assembly 86 may be used. The plug 106 would also aid in preventing any gas in the fluid drawn into the assembly 86 from being transmitted to the earth's surface. An acceptable plug for this application is the Omega™ plug available from Halliburton Energy Services, Inc. Additionally, the plug 106 may have a fluid sampler 108 attached thereto, which may be activated to take a sample of the formation fluid drawn into the assembly 86 when desired. For example, when the sensor 102 indicates that the desired representative formation fluid has been flowed into the assembly 86 , the plug 106 may be deployed with the sampler 108 attached thereto in order to obtain a sample of the formation fluid. The plug 106 may then be reverse circulated to the earth's surface by opening the circulation valve 100 . Of course, in that situation, the plug 106 should be retained uphole from the valve 100 .
[0052] A nipple, no-go 110 , or other engagement device may be provided to prevent the plug 106 from displacing downhole past the disposal sub 96 . When applying pressure to the string 87 to flow the fluid in the assembly 86 outward into the disposal formation 84 , such engagement between the plug 106 and the device 110 may be used to provide a positive indication at the earth's surface that the pumping operation is completed. Additionally, a no-go or other displacement limiting device could be used to prevent the plug 106 from circulating above the upper valve 44 to thereby provide a type of downhole safety valve, if desired.
[0053] The sampler 108 could be configured to take a sample of the fluid in the assembly 86 when the plug 106 engages the device 110 . Note, also, that use of the device 110 is not necessary, since it may be desired to take a sample with the sampler 108 of fluid in the assembly 86 below the disposal sub 96 , etc. The sampler could alternatively be configured to take a sample after a predetermined time period, in response to pressure applied thereto (such as hydrostatic pressure), etc.
[0054] An additional one of the plug 106 may be deployed in order to capture a sample of the fluid in the assembly 86 between the plugs, and then convey this sample to the surface, with the sample still retained between the plugs. This may be accomplished by use of a plug deployment sub, such as that representatively depicted in FIG. 3. Thus, after fluid from the formation 82 is drawn into the assembly 86 , the second plug 106 is deployed, thereby capturing a sample of the fluid between the two plugs. The sample may then be circulated to the earth's surface between the two plugs 106 by, for example, opening the circulating valve 100 and reverse circulating the sample and plugs uphole through the string 87 .
[0055] Referring additionally now to FIG. 3, a fluid separation device or plug deployment sub 112 embodying principles of the present invention is representatively depicted. A plug 106 is releasably secured in a housing 114 of the sub 112 by positioning it between two radially reduced restrictions 116 . If the plug 106 is an Omega™ plug, it is somewhat flexible and can be made to squeeze through either of the restrictions 116 if a sufficient pressure differential is applied across the plug. Of course, either of the restrictions could be made sufficiently small to prevent passage of the plug 106 therethrough, if desired. For example, if it is desired to permit the plug 106 to displace upwardly through the assembly 86 above the sub 112 , but not to displace downwardly past the sub 112 , then the lower restriction 116 may be made sufficiently small, or otherwise configured, to prevent passage of the plug therethrough.
[0056] A bypass passage 118 formed in a sidewall of the housing 114 permits fluid flow therethrough from above, to below, the plug 106 , when a valve 120 is open. Thus, when fluid is being drawn into the assembly 86 in the method 80 , the sub 112 , even though the plug 106 may remain stationary with respect to the housing 114 , does not effectively prevent fluid flow through the assembly. However, when the valve 120 is closed, a pressure differential may be created across the plug 106 , permitting the plug to be deployed for reciprocal movement in the string 87 . The sub 112 may be interconnected in the assembly 86 , for example, below the upper valve 66 and below the plug 106 shown in FIG. 2.
[0057] If a pump, such as pump 94 is used to draw fluid from the formation 82 into the assembly 86 , then use of the low density fluid in the string 87 is unnecessary. With the upper valve 66 closed and the lower valve 58 open, the pump 94 may be operated to flow fluid from the formation 82 into the assembly 86 , and outward through the disposal sub 96 into the disposal formation 84 . The pump 94 may be any conventional pump, such as an electrically operated pump, a fluid operated pump, etc.
[0058] Referring additionally now to FIG. 4, another method 130 of performing a formation test embodying principles of the present invention is representatively depicted. The method 130 is described herein as being used in a “rigless” scenario, i.e., in which a drilling rig is not present at the time the actual test is performed, but it is to be clearly understood that such is not necessary in keeping with the principles of the present invention. Note that the method 80 could also be performed rigless, if a downhole pump is utilized in that method. Additionally, although the method 130 is depicted as being performed in a subsea well, a method incorporating principles of the present invention may be performed on land as well.
[0059] In the method 130 , a tubular string 132 is positioned in the well, preferably after a test formation 134 and a disposal formation 136 have been perforated. However, it is to be understood that the formations 134 , 136 could be perforated when or after the string 132 is conveyed into the well. For example, the string 132 could include perforating guns, etc., to perforate one or both of the formations 134 , 136 when the string is conveyed into the well.
[0060] The string 132 is preferably constructed mainly of a composite material, or another easily milled/drilled material. In this manner, the string 132 may be milled/drilled away after completion of the test, if desired, without the need of using a drilling or workover rig to pull the string. For example, a coiled tubing rig could be utilized, equipped with a drill motor, for disposing of the string 132 .
[0061] When initially run into the well, the string 132 may be conveyed therein using a rig, but the rig could then be moved away, thereby providing substantial cost savings to the well operator. In any event, the string 132 is positioned in the well and, for example, landed in a subsea wellhead 138 .
[0062] The string 132 includes packers 140 , 142 , 144 . Another packer may be provided if it is desired to straddle the test formation 134 , as the test formation 82 is straddled by the packers 24 , 32 shown in FIG. 2. The string 132 further includes ports 146 , 148 , 150 spaced as shown in FIG. 4, i.e., ports 146 positioned below the packer 140 , ports 148 between the packers 142 , 144 , and ports 150 above the packer 144 . Additionally the string 132 includes seal bores 152 , 154 , 156 , 158 and a latching profile 160 therein for engagement with a tester tool 162 as described more fully below.
[0063] The tester tool 162 is preferably conveyed into the string 132 via coiled tubing 164 of the type which has an electrical conductor 165 therein, or another line associated therewith, which may be used for delivery of electrical power, data transmission, etc., between the tool 162 and a remote location, such as a service vessel 166 . The tester tool 162 could alternatively be conveyed on wireline or electric line. Note that other methods of data transmission, such as acoustic, electromagnetic, fiber optic etc. may be utilized in the method 130 , without departing from the principles of the present invention.
[0064] A return flow line 168 is interconnected between the vessel 166 and an annulus 170 formed between the string 132 and the wellbore 12 above the upper packer 144 . This annulus 170 is in fluid communication with the ports 150 and permits return circulation of fluid flowed to the tool 162 via the coiled tubing 164 for purposes described more fully below.
[0065] The ports 146 are in fluid communication with the test formation 134 and, via the interior of the string 132 , with the lower end of the tool 162 . As described below, the tool 162 is used to pump fluid from the formation 134 , via the ports 146 , and out into the disposal formation 136 via the ports 148 .
[0066] Referring additionally now to FIG. 5, the tester tool 162 is schematically and representatively depicted engaged within the string 132 , but apart from the remainder of the well as shown in FIG. 4 for illustrative clarity. Seals 172 , 174 , 176 , 178 sealingly engage bores 152 , 154 , 156 , 158 , respectively. In this manner, a flow passage 180 near the lower end of the tool 162 is in fluid communication with the interior of the string 132 below the ports 148 , but the passage is isolated from the ports 148 and the remainder of the string above the seal bore 152 ; a passage 182 is placed in fluid communication with the ports 148 between the seal bores 152 , 154 and, thereby, with the disposal formation 136 ; and a passage 184 is placed in fluid communication with the ports 150 between the seal bores 156 , 158 and, thereby, with the annulus 170 .
[0067] An upper passage 186 is in fluid communication with the interior of the coiled tubing 164 . Fluid is pumped down the coiled tubing 164 and into the tool 162 via the passage 186 , where it enters a fluid motor or mud motor 188 . The motor 188 is used to drive a pump 190 . However, the pump 190 could be an electrically-operated pump, in which case the coiled tubing 164 could be a wireline and the passages 186 , 184 , seals 176 , 178 , seal bores 156 , 158 , and ports 150 would be unnecessary. The pump 190 draws fluid into the tool 162 via the passage 180 , and discharges it from the tool via the passage 182 . The fluid used to drive the motor 188 is discharged via the passage 184 , enters the annulus, and is returned via the line 168 .
[0068] Interconnected in the passage 180 are a valve 192 , a fluid property sensor 194 , a variable choke 196 , a valve 198 , and a fluid identification sensor 200 . The fluid property sensor 194 may be a pressure, temperature, resistivity, density, flow rate, etc. sensor, or any other type of sensor, or combination of sensors, and may be similar to any of the sensors described above. The fluid identification sensor 200 may be a nuclear magnetic resonance sensor, an acoustic sand probe, or any other type of sensor, or combination of sensors. Preferably, the sensor 194 is used to obtain data regarding physical properties of the fluid entering the tool 162 , and the sensor 200 is used to identify the fluid itself, or any solids, such as sand, carried therewith. For example, if the pump 190 is operated to produce a high rate of flow from the formation 134 , and the sensor 200 indicates that this high rate of flow results in an undesirably large amount of sand production from the formation, the operator will know to produce the formation at a lower flow rate. By pumping at different rates, the operator can determine at what fluid velocity sand is produced, etc. The sensor 200 may also enable the operator to tailor a gravel pack completion to the grain size of the sand identified by the sensor during the test.
[0069] The flow controls 192 , 196 , 198 are merely representative of flow controls which may be provided with the tool 162 . These are preferably electrically operated by means of the electrical line 165 associated with the coiled tubing 164 as described above, although they may be otherwise operated, without departing from the principles of the present invention.
[0070] After exiting the pump 190 , fluid from the formation 134 is discharged into the passage 182 . The passage 182 has valves 202 , 204 , 206 , sensor 208 , and sample chambers 210 , 212 associated therewith. The sensor 208 may be of the same type as the sensor 194 , and is used to monitor the properties, such as pressure, of the fluid being injected into the disposal formation 136 . Each sample chamber has a valve 214 , 216 for interconnecting the chamber to the passage 182 and thereby receiving a sample therein. Each sample chamber may also have another valve 218 , 220 (shown in dashed lines in FIG. 5) for discharge of fluid from the sample chamber into the passage 182 . Each of the valves 202 , 204 , 206 , 214 , 216 , 218 , 220 may be electrically operated via the coiled tubing 164 electrical line as described above.
[0071] The sensors 194 , 200 , 208 may be interconnected to the line 165 for transmission of data to a remote location. Of course, other means of transmitting this data, such as acoustic, electromagnetic, etc., may be used in addition, or in the alternative. Data may also be stored in the tool 162 for later retrieval with the tool.
[0072] To perform a test, the valves 192 , 198 , 204 , 206 are opened and the pump 190 is operated by flowing fluid through the passages 184 , 186 via the coiled tubing 164 . Fluid from the formation 134 is, thus, drawn into the passage 180 and discharged through the passage 182 into the disposal formation 136 as described above.
[0073] When one or more of the sensors 194 , 200 indicate that desired representative formation fluid is flowing through the tool 162 , one or both of the samplers 210 , 212 is opened via one or more of the valves 214 , 216 , 218 , 220 to collect a sample of the formation fluid. The valve 206 may then be closed, so that the fluid sample may be pressurized to the formation 134 pressure in the samplers 210 , 212 before closing the valves 214 , 216 , 218 , 220 . One or more electrical heaters 222 may be used to keep a collected sample at a desired reservoir temperature as the tool 162 is retrieved from the well after the test.
[0074] Note that the pump 190 could be operated in reverse to perform an injection test on the formation 134 . A microfracture test could also be performed in this manner to collect data regarding hydraulic fracturing pressures, etc. Another formation test could be performed after the microfracture test to evaluate the results of the microfracture operation. As another alternative, a chamber of stimulation fluid, such as acid, could be carried with the tool 162 and pumped into the formation 134 by the pump 190 . Then, another formation test could be performed to evaluate the results of the stimulation operation. Note that fluid could also be pumped directly from the passage 186 to the passage 180 using a suitable bypass passage 224 and valve 226 to directly pump stimulation fluids into the formation 134 , if desired.
[0075] The valve 202 is used to flush the passage 182 with fluid from the passage 186 , if desired. To do this, the valves 202 , 204 , 206 are opened and fluid is circulated from the passage 186 , through the passage 182 , and out into the wellbore 12 via the port 148 .
[0076] Referring additionally now to FIG. 6, another method 240 embodying principles of the present invention is representatively illustrated. The method 240 is similar in many respects to the method 130 described above, and elements shown in FIG. 6 which are similar to those previously described are indicated using the same reference numbers.
[0077] In the method 240 , a tester tool 242 is conveyed into the wellbore 12 on coiled tubing 164 after the formations 134 , 136 have been perforated, if necessary. Of course, other means of conveying the tool 242 into the well may be used, and the formations 134 , 136 may be perforated after conveyance of the tool into the well, without departing from the principles of the present invention.
[0078] The tool 242 differs from the tool 162 described above and shown in FIGS. 4 & 5 in part in that the tool 242 carries packers 244 , 246 , 248 thereon, and so there is no need to separately install the tubing string 132 in the well as in the method 130 . Thus, the method 240 may be performed without the need of a rig to install the tubing string 132 . However, it is to be clearly understood that a rig may be used in a method incorporating principles of the present invention.
[0079] As shown in FIG. 6, the tool 242 has been conveyed into the well, positioned opposite the formations 134 , 136 , and the packers 244 , 246 , 248 have been set. The upper packers 244 , 246 are set straddling the disposal formation 136 . The passage 182 exits the tool 242 between the upper packers 244 , 246 , and so the passage is in fluid communication with the formation 136 . The packer 248 is set above the test formation 134 . The passage 180 exits the tool 242 below the packer 248 , and the passage is in fluid communication with the formation 134 . A sump packer 250 is shown set in the well below the formation 134 , so that the packers 248 , 250 straddle the formation 134 and isolate it from the remainder of the well, but it is to be clearly understood that use of the packer 250 is not necessary in the method 240 .
[0080] Operation of the tool 242 is similar to the operation of the tool 162 as described above. Fluid is circulated through the coiled tubing string 164 to cause the motor 188 to drive the pump 190 . In this manner, fluid from the formation 134 is drawn into the tool 242 via the passage 180 and discharged into the disposal formation 136 via the passage 182 . Of course, fluid may also be injected into the formation 134 as described above for the method 130 , the pump 190 may be electrically operated (e.g., using the line 165 or a wireline on which the tool is conveyed), etc.
[0081] Since a rig is not required in the method 240 , the method may be performed without a rig present, or while a rig is being otherwise utilized. For example, in FIG. 6, the method 240 is shown being performed from a drill ship 252 which has a drilling rig 254 mounted thereon. The rig 254 is being utilized to drill another wellbore via a riser 256 interconnected to a template 258 on the seabed, while the testing operation of the method 240 is being performed in the adjacent wellbore 12 . In this manner, the well operator realizes significant cost and time benefits, since the testing and drilling operations may be performed simultaneously from the same vessel 252 .
[0082] Data generated by the sensors 194 , 200 , 208 may be stored in the tool 242 for later retrieval with the tool, or the data may be transmitted to a remote location, such as the earth's surface, via the line 165 or other data transmission means. For example, electromagnetic, acoustic, or other data communication technology may be utilized to transmit the sensor 194 , 200 , 208 data in real time.
[0083] Of course, a person skilled in the art would, upon a careful reading of the above description of representative embodiments of the present invention, readily appreciate that modifications, additions, substitutions, deletions and other changes may be made to these embodiments, and such changes are contemplated by the principles of the present invention. For example, although the methods 10 , 80 , 130 , 240 are described above as being performed in cased wellbores, they may also be performed in uncased wellbores, or uncased portions of wellbores, by exchanging the described packers, tester valves, etc. for their open hole equivalents. The foregoing detailed description is to be clearly understood as being given by way of illustration and example only. | Methods and apparatus are provided which permit well testing operations to be performed downhole in a subterranean well. In various described methods, fluids flowed from a formation during a test may be disposed of downhole by injecting the fluids into the formation from which they were produced, or by injecting the fluids into another formation. In several of the embodiments of the invention, apparatus utilized in the methods permit convenient retrieval of samples of the formation fluids and provide enhanced data acquisition for monitoring of the test and for evaluation of the formation fluids. | 4 |
TECHNICAL FIELD
The present invention relates to a device and a method for successively changing elongated sheets or similar flexible objects from an active viewable position to a non-active, non-viewable position, said device comprising a rotatable drum to which the flexible objects are attached, a motor arranged for driving the rotatable drum in two opposing rotational directions, and a controller unit for controlling the rotational speed and direction of the motor.
BACKGROUND ART
In the commercial world of today more and more advertising is made. Stores are using advertisement posters to communicate their messages to the public. However, space is sometimes a limiting factor when it comes to exposing posters. To solve this problem it is known to use devices, which are capable of changing posters, by for instance rotating an “endless” belt or band consisting of many individual posters through a cylinder arrangement. In this fashion one surface may be used to display several different messages or advertisements.
However many of the known devices are usually complicated to handle, because of their complex design. For instance it might take a long time and be complicated to change a set of posters for new ones. The complexity with many different parts also contributes to the high cost for such devices.
One improved device is described in EP 883 875. This device comprises a drum on which different posters can be wound up and unwound. The posters are attached to the drum with the same distance therein between and by rotating the drum in a certain way and in different directions it is possible to show one poster at a time. A mechanical circuit controls the timing of the drums rotation, even if it is mentioned that it would be possible to use an electrical circuit. However, it is not further described how the electrical circuit could be realised. The mechanical circuit is complex and consists of a lot of different parts. One other aspect of the mechanical circuit is that it is noisy and different timing aspects have to be set in a mechanical way, which make it limited when it comes to set different time intervals.
A drawback with the device according to EP 883 875 is that it requires a strong motor when the posters or any other flexible objects become large and thereby heavy. Thus, it is important with a sufficient power supply. A large motor is of course also noisier than a small one.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a device for changing elongated flexible objects, which is much more energy efficient, silent, user friendly and reliable than today's devices.
The above object is according to the present invention solved by that the drum of the device comprises a balancing spring that is arranged to be preloaded during the unwinding of the flexible objects and providing a lifting force when the flexible objects are wound up whilst still allowing the device to retain the functionality of previous devices.
The present invention also describes a method for user-friendly attachment of the flexible objects as well as a method for self-calibration.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described in more detail in relation to the enclosed drawings, in which:
FIG. 1 schematically shows the device for changing elongated flexible objects, partly in cross section.
FIG. 2 shows the device according to FIG. 1 , having posters attached to it. The arrow indicates the preferred direction of a spectator.
FIG. 3 shows the device according to FIG. 1 and FIG. 2 , but looking at the preferred back side of the posters.
FIG. 4 shows a perspective view of the freewheeling balancing spring assembly. One end of the balancing spring 16 is fixed to the end cover 7 . The other end of the balancing spring 16 is connected to the journal 15 via a freewheeling clutch 17 .
FIG. 4A shows a perspective view of the structural design of the freewheeling clutch 17 .
FIG. 4B shows a cross section of the structural design of the freewheeling clutch 17 .
FIG. 4C shows a perspective view of an alternative embodiment of a freewheeling clutch 117 .
FIGS. 5 to 10 depict in sequence the process by which the device changes the exposed poster.
FIG. 11 shows in detail how the posters may be attached according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiment of the present invention will now be described. First of all the parts comprising the device will be described as depicted in the partly cross sectional view of FIG. 1 .
The device comprises a drum 1 with rotational freedom between two end holding means 2 , 3 , preferably in the shape of discs. At each end the drum 1 is fitted with end covers 6 and 7 respectively. From a first end holding means 2 a motor holding bar 10 protrudes through the end cover 6 . A motor 11 for rotating the drum 1 of the device is provided inside the drum 1 and is held in place by the motor holding bar 10 . A controller unit 13 for controlling the speed and direction of the motor 11 as well as other aspects of the operation of the device is mounted on the motor holding bar 10 . The motor 11 exerts its torque to the drum 1 via a driving disc 14 . An output shaft 12 from the motor 11 is connected to the driving disc 14 in such a way that when the shaft 12 rotates the driving disc 14 also rotates. At the opposite end of the drum 1 a journal 15 protrudes from a second end holding means 3 through the end cover 7 . The journal 15 is rigidly connected to the second end holding means 3 . A freewheeling clutch 17 is provided towards the end of the journal 15 . A balancing spring 16 is connected to the end cover 7 at one end and to the freewheeling clutch 17 at the other end.
The motor holding bar 10 and the first end holding means 2 are fixed connected and may be produced as a single part, e.g. welded. The same applies to the second end holding means 3 , which may be combined with the journal 15 into a single part. In order to minimize friction as the drum 1 rotates bearings 8 and 9 are housed in the end covers 6 and 7 . The end holding means 2 and 3 must not be allowed to rotate more than a small distance with reference to each other and may therefore be directly locked to each other or even produced as a single part.
Protruding from the first end holding means 2 is a girder 18 containing a magnet 19 and identifying means 20 .
Suspension means 4 and 5 , e.g. in the shape of hooks, may be added to the device in order to facilitate installation from ceiling, wall or a particular stand. The suspension means 4 and 5 engage the holding means 2 and 3 . In order to use the device for its main purpose, flexible elongated objects 100 - 400 , referred to as posters, are attached to the drum 1 , as depicted in FIGS. 2 and 3 . Expecting that the posters 100 - 400 are fully wound out, one of them will be exposed to a viewer in front of the device. Arrow 80 in FIG. 2 indicates this viewable direction. In order to provide a means for the controller unit 13 to calibrate the position of the posters or derive other necessary information about the system, an identifiable magnetically attractable object 110 , referred to as identification strip, is attached to at least one of the posters, e.g. the poster 100 as depicted in FIGS. 3 , 5 , 6 , 7 , 8 and 10 . The identification strip 110 may however be integrated into the very fabric of the poster 100 , e.g. by use of special thread or printing ink.
The principle of operation will be described below.
In order to describe the new functionality introduced by the present invention it is necessary to summarize the main function of changing and displaying posters. This function is in itself not unique to the present invention and can be found in the existing invention, EP 883 875. However the additional new functionality added by the present invention is clearly described below.
According to FIG. 5 poster 400 is in an exposed state. The device is depicted with 4 posters, but the device can easily be used with other numbers of posters attached to the drum 1 . In order to display another poster the device will start to turn the drum 1 counterclockwise around its axis according to the arrow 90 in FIG. 6 thus winding up the attached posters 100 - 400 . Eventually, as the objects are fully wound up, the one object that was furthest back when starting to wind up, in this case poster 100 , will fall over the top as depicted by arrow 94 in FIG. 9 and thereby become the front object. As this happens the device reverses the rotation of the drum 1 , winding the posters 100 - 400 down clockwise which is indicated by the arrow 95 seen in FIG. 10 . This motion continues until the newly exposed poster 100 is fully exposed. The device then stops, exposing the object for an arbitrarily set amount of time after which the cycle repeats for the next poster to be shown and so on. The device can however be interrupted at any time, during any part of the cycle, without affecting the function of the device as long as this does not cause any loss of information regarding the exact position of the posters. For instance it may be preferred to halt the device as the newly exposed poster falls over the top of the drum 1 or pause the unwinding midways. This can be achieved either by direct input from the user or as part of a pre-programmed procedure, but it is outside the scope of this text to describe this any further as it is easily realized by a person skilled in the art.
It should be noted that even though the motion consists of both clockwise and counterclockwise rotation the total sum of all rotation has to be counterclockwise with reference to FIGS. 5 to 10 . In order to successively change the posters the drum 1 is turned a certain amount more counterclockwise than clockwise for every object. For a set of two posters that amount is ½ of a revolution, for a set of three it is ⅓ of a revolution and so on. A prerequisite for this is that the elongated flexible objects 200 - 400 are attached to the carrier flexible object 100 at distances of ½ the drum circumference for a number of two posters, ⅓ the drum circumference for a number of three posters, ¼ for a number of four posters and so on.
Below the function of the balancing spring assembly is described in detail. In order to wind up the posters 100 - 400 it is necessary that the motor 11 driving the system produces a lifting force to overcome the weight of the poster 100 - 400 . By introducing a spring 16 that is connected to the drum 1 , via the end cover 7 , at one end and to the journal 15 , via the freewheeling clutch 17 , at the other end it is possible to preload the device in such a way that the force of the spring 16 balances the weight of the posters 100 - 400 to a high degree. The spring 16 is therefore referred to as a balancing spring. When the posters 100 - 400 are completely wound up the balancing spring 16 is not loaded at all, i.e. has no inherent load. As the posters 100 - 400 are wound down the balancing spring 16 is spun and thereby continuously gets preloaded enough to balance the weight of the posters 100 - 400 . Similarly as the posters 100 - 400 are wound up the balancing spring 16 continues to provide this lifting force.
This means that instead of having to lift the entire weight of the objects the motor only has to provide enough force for acceleration. Thereby the physical requirements of the motor are reduced significantly, indirectly reducing noise and power consumption as well.
The balancing spring 16 is fixed connected to the drum 1 via end cover 7 . At the start of winding down a poster the balancing spring 16 is supposed to provide no lifting force. This also has to comply with the inherent function of the device to successively rotate the drum 1 slightly more counterclockwise than clockwise for every poster changed. Therefore the balancing spring 16 is connected via a freewheeling clutch 17 to the journal 15 . This allows the balancing spring, end cover, drum-package to freewheel counterclockwise without preloading the balancing spring 16 whereas clockwise rotation is clutched meaning that the balancing spring 16 is preloaded. In this way the device is allowed continuous counterclockwise motion whilst still benefiting from having the weight of the posters 100 - 400 balanced. In FIG. 4 the balancing spring 16 is depicted as a torsion spring as this is the preferred embodiment, but it should be realized that other types of springs may be used to achieve the objective of balancing the weight of the posters.
In FIGS. 4A and 4B the structural design of the freewheeling clutch 17 is shown schematically. The freewheeling clutch 17 thus constitutes of a so called one way needle clutch. The outer ring 21 is provided with a number of segments 22 on its inner side, said segments 22 defining rolling surfaces for a number of rollers/needles 23 that are included in the one way needle clutch 17 . The segments 22 have a varying distance in relation to the center of the one way needle clutch 17 in the circumferential direction of the outer ring 21 . Therefore, adjacent segments 22 are connected by radial steps 24 . By studying FIG. 4B it is realized that when the outer ring 21 is rotated in counter clockwise direction/CCW the rollers 23 abut the steps 24 and the rotation is permitted. If the outer ring 21 is rotated in a direction opposite to CCW the rollers 23 will be jammed between the outer ring 21 and a central cylindrical body 25 of the one way needle clutch 17 . Thus rotation is prohibited.
If the balancing spring 16 was directly fixed to both the journal 15 and drum 1 , i.e. no freewheeling clutch was present, it would in order to comply with the incremental counterclockwise rotation be increasingly preloaded in the wrong direction and the device would eventually either break down from destroying the balancing spring 16 or stall due to insufficient motor torque.
In FIG. 4C an alternative design of a freewheeling clutch 117 is shown. In this connection it should be pointed out that the arrangement shown in FIG. 4C is reversed compared to the arrangement shown in FIG. 4 . Thus, the freewheeling clutch 117 is integrated with the end cover 107 and one end of the balancing spring 116 is in engagement with said freewheeling clutch 117 . The other end of the balancing spring 116 is fixedly connected to the journal 115 at a distance from the end cover 107 that generally corresponds to the length of the balancing spring 116 . The freewheeling clutch 117 comprises a number of bosses 140 distributed around the journal 115 . The bosses 140 comprise an end surface 141 and a sloping surface 142 that extends from the end surface 141 to the inner surface of the end cover 107 . As the posters are unwound from the drum the balancing spring 116 will abut against the end surface 141 of the bosses 140 of the end cover 107 and thereby taking load, contributing a lifting force countering some or all of the weight of the posters. Then as the posters are wound up on the drum this abutment will still be in effect and the balancing spring 116 will continue to provide a lifting force. When the posters are once again fully wound up the balancing spring 116 will reach an unloaded state. Continuing in this winding up direction there are however no bosses to obstruct the movement of the balancing spring 116 . Hence during any further movement in the winding up direction the balancing spring 116 will be free to slide on the sloping surfaces 142 of the bosses 140 and no preloading of the balancing spring 116 will be effected.
In order to accomplish the proper function of the device according to the preferred embodiment described earlier we may define the degrees of freedom of the internal parts as follows.
The end covers 6 and 7 are provided freely rotatable with reference to journal 15 and motor holding bar 10 allowing the integration of ball bearings 8 , 9 for lower friction or simply relying on sleeve bearings. The end covers 6 and 7 as well as the driving disc 14 are all fixed connected to the drum 1 . The motor axis 12 is also fixed connected to the drum 1 via the driving disc 14 . The motor 11 is fixed connected to the first end holding means 2 via the motor holding bar 10 to which also the controller unit 13 may be attached. The journal 15 and motor holding bar 10 are fixed connected to the first and second end holding means 2 and 3 respectively. The end holding means 2 and 3 need with reference to each other to allow no more than a few degrees of rotational freedom. This can either be achieved by providing the device with a crossbar or relying on the mounting of the device, i.e. letting the wall, ceiling or other device support restrict the rotation of the end holding means 2 and 3 . The balancing spring 16 is fixed connected to the end cover 7 . The other end of the balancing spring 16 is via the freewheeling clutch 17 allowed free rotation around the axis of the journal 15 in only one direction.
The function of the magnet assembly will be described below.
In order to successively change the posters 100 - 400 in a correct manner it is of utmost importance that the reversal of the rotation of the drum 1 occurs at the right position according to FIGS. 9 and 10 . The posters 100 - 400 can be pre-arranged on the drum 1 for this to be accomplished and the controller unit 13 can be programmed to function according to these fixed positions. This does however require the user of the device to manually calibrate the device to the posters 100 - 400 and leaves the device completely unable to self-correct any shift from this calibration.
According to the function of the device, as the end of the poster to be exposed reaches the position on the drum 1 where it will fall over, the rotational direction of the drum 1 is reversed in order to expose this poster. It is necessary that this reversal occurs at a specific point in order to guarantee the function of the device. If the reversal is performed too early the next poster will not fall over and be exposed. If the reversal is too late there is a risk that the succeeding poster will also fall over, compromising the function of the device. The device therefore needs to be calibrated with the posters. The calibration signal can also be used by the controller unit 13 to determine whether the device is functioning properly and take care of any such detected problems should they arise.
One such means of calibration is depicted in FIGS. 3 , 5 , 6 , 7 , 8 and 10 . An identification strip 110 is attached to one of the posters near or at the end of the poster. The device is fitted with a magnet 19 on the protruding girder 18 . On this girder 18 close to the magnet 19 are means for identifying the end of the poster, referred to as identifying means 20 . As the magnetically attractable identification strip 110 comes into proximity of the magnet 19 it is pulled towards the magnet and the accompanying identifying means 20 as depicted by arrow 91 in FIG. 6 whereby a signal is sent to the controller unit 13 , indicating that one of the posters is near the top of the drum 1 . There are several different techniques available for constructing the identifying means 20 . They may for instance comprise an inductive sensor or one or more electric contact points, integrate an optic sensor device etc. but by bringing the end of the poster so close to the identifying means 20 , precision and functionality is increased regardless of the method used for identification.
As the drum 1 is turning counterclockwise/CCW winding up the posters it will stretch the end of the poster 100 as the identification strip 110 is held back by the magnet 19 . Eventually the poster 100 cannot be stretched any further and is released from the magnet 19 as depicted in FIG. 8 . This point of release is of very high accuracy and is preferably the one used for calibrating the position of the posters.
Both of the signals mentioned above can be used as information for the controller unit 13 to determine the exact position of the posters. However, preferably the latter signal is used since the disengagement point of the identification strip 110 and the magnet 19 can easily achieve far greater accuracy than the engagement point. This is due to the very controlled nature of a stretched poster compared to the uncontrolled nature of an unstretched poster.
The device will in this way use the signal in order to determine the correct position at which to reverse the direction of the drum 1 . Preferably this position is slightly after the identification strip 110 has disengaged the magnet 19 in order to ensure that the identification strip 110 is no longer influenced by the magnet and there is no chance of it being pulled back towards the magnet 19 as the rotation of the drum 1 is reversed.
For the next poster the position of reversal can easily be calculated by the controller unit 13 by adding ⅓, ¼ drum revolution etc. counterclockwise rotation according to the method described earlier. An identification strip 110 is therefore only necessary on one of the posters. It should however be understood that an identification strip can be attached to each and every of the posters e.g. in order to further enhance reliability of the device.
Although the most likely setup is having the identification strip 110 made of a passive material that will interact with the magnetic field of a magnet 19 it is also possible to make an identification strip 110 that is permanently magnetic whereby the magnet 19 can be replaced with a magnetically attractable material, e.g. soft iron. It is also possible to make the entire fabric of a poster or a part of it magnetic by use of special thread or printing ink. Furthermore the magnetic field provided either by the magnet 19 or by the identification strip 110 can be produced by means of an electro magnet having the benefit of being possible to turn on and off.
The advantages given to the device by magnetically attracting the posters towards the identifying means 20 can be summarized as improving the cost-efficiency, accuracy and reliability of calibration. It also has a self-cleaning effect as the identification strip 110 is forced to slide across the surface of the girder 18 thereby keeping surfaces free from corrosion or dust.
A method for attaching the posters to the device will be described below.
The posters 100 - 400 can be attached to the drum 1 in a variety of ways. In one preferred embodiment of the present invention the posters 100 - 400 are attached to each other as a separate package as depicted in FIG. 11 before being fixed to the drum 1 . The first poster 100 being the carrier for the other posters needs to be a certain amount longer than the other posters in order to achieve proper exposure. The other posters are then attached to this carrier poster 100 at certain distances determined by the diameter of the drum 1 and the total number of posters.
Preferably, the posters are attached at the same mutual distance around the drum 1 in order to make it easier to program the controller unit 13 and also enhance the changing of the posters. However, it is also possible to provide the posters at different mutual distances to each other. The posters themselves might also be provided, if necessary, with weights such that the posters always appear in a stretched state.
When using a single identification strip 110 it can be provided on any of the posters 100 - 400 in order to achieve calibration of the poster position. By placing it on the carrier poster 100 as depicted in FIG. 11 it can however fulfill yet another objective. When a user wishes to switch the set of posters 100 - 400 for another set of posters and the principle of a carrier poster 100 is applied it is necessary that the carrier poster 100 is the front-most poster being exposed. The particular carrier poster 100 can be sorted out by the device given that the identification strip 110 is attached to said poster 100 . During calibration as the identification strip 110 is recognized by the device and the poster 100 subsequently is changed to being the front-most poster the user can easily stop the device and efficiently make the desired switch of poster sets.
It should be understood that the design of the device can differ from the schematic view of FIG. 1 . The drum 1 may for instance be made very narrow or even solid forcing the motor and balancing spring mechanisms to be outside the drum 1 . It is however believed to be very advantageous both in a practical, economical and design sense to use the drum 1 as a housing for motor, balancing mechanisms, controller units etc. The balancing spring 16 and freewheeling clutch 17 as well as identifying means 20 and the identification strip 110 can be physically realized in a number of ways but in order to be utilized properly by the device they need to interact with each other in the ways described earlier. It shall be understood that even if the invention has been described with reference to preferred embodiments the invention is not limited thereto. Features from one embodiment may for example be used together with other embodiments. Thus, the features described above may be combined in any desired combination. There are many embodiments and variations that are within the scope of the invention, which are best defined by the accompanying claims.
FEASIBLE MODIFICATIONS OF THE INVENTION
In the embodiment described above the girder 18 is provided with one magnet 19 . However, within the scope of the present invention it is feasible to have more than one magnet. | A device for successively changing elongated flexible objects from an active viewable position to a non-active, non-viewable position includes a rotatable drum to which the flexible objects are attached, a motor driving the rotatable drum in opposing rotational directions, and a controller unit controlling motor speed and direction. A balancing spring is preloaded when the flexible objects are unwound from the drum, providing a lifting force when the flexible objects are wound up on the drum. By using a freewheeling clutch, preloading only occurs in one rotational direction, the balancing spring freewheeling in the other direction, taking no load. Utilizing a magnetically interactive identification strip the device gains highly accurate information on the position of the flexible elongated objects. By pre-attaching the flexible elongated objects on each other and providing the identification strip on the designated carrier flexible object exchanging the set of flexible elongated objects is made very simple. | 8 |
REFERENCE TO RELATED APPLICATION
This application is the national stage under 35 USC 371 of International Application No. PCT/EP2007/009131, filed Oct. 22, 2007, which claims the priority of German Patent Application No. 20 2006 016 093.0, filed Oct. 20, 2006, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a solids distributor for injection plants, in particular for blast furnaces, with a chamber and with a plurality of lance lines leading away, the chamber having a supply connection for a solid, such as ground coal, which is to be distributed. The invention relates, further, to a distributor head for such a solids distributor.
BACKGROUND OF THE INVENTION
For the heating of blast furnaces, burners in power stations and similar apparatus, ground solid fuel, in particular coal, is increasingly used as fuel. This affords the advantage that, as compared with the combustible material conventionally used, such as coke, or even oil, a marked saving in terms of operating costs becomes possible. In order to allow uniform supply of the ground fuel into the furnace, a multiplicity of nozzle lances are usually arranged around the furnace. The ground fuel is supplied to them via individual lines (“lance lines”). In order to distribute the ground fuel, supplied by a grinding device, such as a coal mill, or an interposed conveying device, to the individual lines leading to the lances, a fuel distributor is provided. This has a chamber, to which the ground fuel is supplied via a connection. A multiplicity of individual lines lead from the chamber to the respective lances. One difficulty of this is that, in practice, an uneven distribution of the ground fuel to the individual lines often occurs, with the result that different quantities are supplied to the individual lances. This leads to different combustion and consequently to uneven heating of the individual fuel nozzles, this being undesirable.
In order to achieve an equalization and regulation of the supply to the individual lances, a coal distributor became known which has individual quantity controls on the individual lines leading to the lances (SU-A-1717640). One disadvantage of the solution is that it becomes increasingly more complicated with a rising number of lines, and, moreover, an only inadequate result is often achieved in spite of the considerable outlay. This applies particularly when the ground coal is supplied to the coal distributor over a relatively long delivery distance.
In another approach, a coal distributor is provided which has a pressure vessel with a chamber arranged below it (DE-C-3603078). In this case, the chamber is divided into a plurality of subchambers separated from one another, in each case one of the lance lines being connected to each subchamber. Further, a bottom connection for the supply of carrier gas is provided on each subchamber. However, distribution to the subchambers cannot achieve a sufficient equalization of the feed streams in the lance lines, and therefore individual controls on the lance lines have to be adopted in order to compensate quantitative differences. This is complicated.
SUMMARY OF THE INVENTION
The object on which the invention is based is, starting from the prior art last mentioned, to improve a solids distributor of the type initially mentioned, to the effect that a better equalization is achieved at a low outlay.
The solution according to the invention lies in the features of invention as broadly described herein. Advantageous developments are the subject matter of the detailed description below.
According to the invention, in a solids distributor for injection plants, in particular for blast furnaces, with a chamber and with a plurality of lance lines leading away, the chamber having a supply connection for a solid to be distributed, there is provision for the chamber to be a collecting chamber surrounded by a common wall, so that the lance lines connected to it are connected to one another within the collecting chamber, there being arranged geodetically above the collecting chamber a pressure vessel, the lower part of which is designed as a bunker and has an outlet connected to the supply connection and, further, the upper part of which is designed as a gas space.
The essence of the invention is to provide the distributor with a collecting chamber which is surrounded by a common wall to which the lance lines are connected directly. The invention has recognized that a substantial cause of the unsatisfactory quality of the distribution to the lance lines is a segregation of the solid supplied from its feed gas. As a result, the solid no longer reaches the distributor and the lance lines in a homogeneous distribution, and therefore an uneven pulsating mass flow is obtained. These inhomogeneities are so great and have such dynamics that they can often no longer be compensated by means of the individual controls used according to the prior art on the individual lance lines; distributors with individual chambers, to which a lance line is connected in each case, are just as incapable of ensuring the required compensation.
The merit of the invention is to recognize that the adverse consequences of segregation can be effectively counteracted only by means of an improved original distribution in the distributor itself, specifically by the lance lines being connected to the common wall, thus relieving the individual lance controls or ideally making them superfluous. It is preferable to design the junctions between the connections for the lance lines within the collecting chamber as an annular slot. The annular slot causes a tangential flow direction which is especially efficient for compensation between the radially directed substance flows into the lance lines. In this case, the annular slot can be provided in a simple way, for example by means of a displacement body which is arranged centrally in the collecting chamber and the outside of which is spaced apart from the peripheral common wall and therefore forms an annular slot. Preferably, the displacement body is designed to taper upward, that is to say in the direction of the pressure vessel. The outer casing of said displacement body consequently forms a sloping surface with respect to the solid entering the collecting chamber and therefore itself contributes to distribution to the individual lance lines. In particular, by means of such a centrally arranged displacement body, the formation of skeins, in which a preferred flow channel into one of the lance lines forms in the material, can be effectively counteracted. A conical displacement body can be produced particularly expediently and at low outlay.
The invention thus makes it possible to dispense with the complicated individual lance control provided in the prior art. Furthermore, it also makes it possible to supply the solid over a longer delivery distance upstream of the distributor. Even greater flexibility in the supply of solids is therefore additionally achieved, so that the invention is also well suited to the retrofitting or conversion of existing plants.
The term “solid” is to be understood in the present context as meaning fine-grained or coarse-grained stock. This is preferably those materials which serve as fuel, such as, in particular, coal, for the charging of power station burners and the firing of gas furnaces, lime shaft kilns or glass melting furnaces. However, it is not necessarily fuel, but may also be material to be processed.
With the solid being located in the bunker of the pressure vessel, a decoupling of the charging of the lances from the preceding feed is obtained. Pressure fluctuations, such as occur particularly due to pulsations in the supply to the pressure vessel, can therefore no longer reach the collecting chamber or reach it only in a highly damped manner. Moreover, fluctuations in the feed flow lead merely to variations in the solid filling level in the pressure vessel, and the outflows flowing into the lance lines remain unchanged. An appreciable improvement with regard to the uniform distribution of the solid supplied to the collecting chamber into the individual lance lines is thus achieved.
Expediently, a regulating device is provided which acts on the solid located in the bunker. By the supply being varied, equalization, even under changing load conditions, can be achieved here. It is particularly preferable if the regulating device is a filling height control for the solid. It is designed to keep the filling height in the vessel as constant as possible. Further, it may be designed to ensure that a minimum filling height is maintained during operation. Expediently, the actual height is determined via a determination of the weight of the overall vessel which for this purpose is mounted on load cells. However, the height may also be measured directly, for example by means of capacitive or microwave sensors.
The regulating device may also be designed as pressure control. It serves for regulating the gas pressure which acts upon the solid supplied. In the simplest instance, for this purpose, a pressure sensor is provided in the gas space of the pressure vessel. Preferably, however, the pressure at a lower point is used, to be precise level with the connection of the lance lines to the common wall of the collecting chamber. Consequently, a decrease in the solid stream through the lance lines in the case of a decreasing filling level in the pressure vessel, such as occurs in pressure control on the gas space, is avoided. Pressure control is preferably connected to the gas space via a filter resistant to pressure pulses. Robust operation, even under rough conditions, is thereby ensured.
Expediently, a regulatable nitrogen infeed is additionally arranged on the gas space of the pressure vessel. This infeed makes it possible to stabilize more effectively the pressure in the pressure vessel or in the distributor collecting chamber connected to it, and, if appropriate, to adapt said pressure sensitively according to the requirements arising as a result of the operating states. Particularly in combination with the pressure regulating device, a closed loop can thus be formed, by means of which even pronounced fluctuations in the supply of the solid, such as may occur particularly over greater distances or in the case of a multiflow supply, can be smoothed out.
The pressure vessel is preferably arranged directly on the collecting chamber. The solid which accumulates in the lower part of the pressure vessel, said part being designed as a bunker, can then pass directly into the collecting chamber of the distributor solely under the influence of gravity without any further obstacle. A both more reliable and more uniform supply into the collecting chamber is consequently achieved. The bunker is expediently of funnel-shaped design. Even if the solid quantities located in the pressure vessel are small, a reliable feed is thus ensured, whereas, when quantities located in the bunker are large, the filling height and, consequently, the static pressure acting on the supply connection rise only underproportionally. Further equalization is consequently achieved. The situation should not be ruled out, however, where the pressure vessel is connected to the supply connection of the collecting chamber via a downpipe, in which case the downpipe may run vertically or even at an inclination. It is essential that the pressure vessel is located geodetically above the collecting chamber.
For a further improvement in uniformity, there may be provision for a specific individual line control unit to be arranged in each case additionally on the lance lines. An especially high degree of uniformity can consequently be achieved. Individual line controls for lance lines are known per se. Since a high fundamental uniformity between the individual lance lines is already achieved by virtue of the arrangement according to the invention, the preconditions are afforded for achieving virtually perfect equalization by means of an individual line control which acts with particular sensitivity. As a further optional or alternative possibility for further equalization, gas supplies may be provided which preferably issue on the bottom of the collecting chamber. They bring about an additional ventilation of the distributor from below, thus achieving further system decoupling.
The invention extends, further, to a distributor head as described herein. It is suitable particularly for building under existing pressure vessels and, consequently, for the simple retrofitting of conventional solids distribution plants already existing.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained below with reference to the accompanying drawing which illustrates an advantageous exemplary embodiment and in which:
FIG. 1 shows a diagrammatic view of a supply plant for pulverized coal;
FIG. 2 shows a diagrammatic view of a coal distributor with a pressure vessel according to one exemplary embodiment of the invention; and
FIG. 3 shows a perspective view of a distributor head according to a second exemplary embodiment.
DETAILED DESCRIPTION OF THE INVENTION
The invention is explained by the example of a plant which supplies ground coal as solid fuel to a blast furnace. The plant, illustrated in FIG. 1 , for the supply of pulverized coal is of double-flow design. This means that two parallel strings are provided, which are constructed identically to one another. Only one string is therefore described in more detail below; the statements apply correspondingly to the other string.
Coal 9 is supplied from above to a conveying plant 2 via a feed port 1 . The conveying plant may be designed as a twin pressure vessel plant known per se.
The ground coal passes into a supply line 3 , by means of which it is supplied to a coal distributor 6 at a blast furnace 99 (illustrated for only one string). The line 3 may have a considerable length, distances of several hundred meters up to one kilometer being possible.
The supply line 3 issues in the upper region, designed as a gas space 41 , of a pressure vessel 4 of the coal distributor 6 . Its lower region is designed as a coal bunker 42 . The coal passes out of the coal bunker 42 into a distributor head 7 , arranged below the pressure vessel 4 , of the coal distributor. In the exemplary embodiment illustrated, in one string, the pressure vessel 4 is arranged exactly above the distributor head 7 , although this is not absolutely necessary. An arrangement geodetically above the distributor head 7 is sufficient, while the junction may also take place via an oblique downpipe 67 , as illustrated in the other string. The distributor head 7 distributes the coal supplied via the pressure vessel 4 to a multiplicity of lance lines 90 which lead to nozzles 91 on the blast furnace 99 .
Reference is made, then, to FIG. 2 . The pressure vessel 4 has an approximately cylindrical configuration in its upper region functioning as a gas space 41 . In its lower region functioning as a coal bunker 42 , the pressure vessel 4 has a shape tapering conically downward. The line 3 , via which the ground coal is supplied, issues in the region of the gas space 41 at an inlet connection 43 . A pressure regulating device 5 is arranged in the upper region of the gas space 41 . It comprises a filter 51 which is connected at its end to the upper vertex of the gas space 41 and the other end of which is connected to a discharge line 53 . The discharge line 53 contains a regulating valve 52 which is connected to a control device 59 . Further, a pressure sensor 54 and a filling level sensor are provided, which measure the gas pressure and the filling level prevailing in the gas space 41 and which transmit these as a measurement signal to the control device 59 . The filling level measurement may take place directly, for example via a radar sensor 58 , or indirectly via load cells 58 ′ which are arranged in the foundation of the pressure vessel 4 and which determine its overall weight and, from this, the respective filling level. The embodiment illustrated shows, further, an optional nitrogen infeed. This comprises a nitrogen line 57 which is connected via an actuating valve 56 to a gas connection 55 in the upper region of the gas space 41 of the pressure vessel. The actuating valve 56 of the nitrogen infeed is likewise connected to the control device 59 .
At the lower end of the pressure vessel 4 , an outlet port 47 is formed. This is placed directly onto a corresponding supply connection 77 of the distributor head 7 . This gives rise to a direct and continuous junction from the coal bunker 42 into a common collecting chamber 72 of the distributor head 7 . The common collecting chamber 72 is surrounded by a single peripheral cylindrical wall 73 in which a plurality of ports 74 are formed. The ports 74 are distributed at equal intervals, approximately at mid-height, over the circumference of the wall 73 . They function as connections for lance lines 90 and connect the collecting chamber 72 to the nozzles 91 arranged on the blast furnace. The collecting chamber 72 is closed, pressure-resistant, upward and downward by means of a bottom plate 75 and a cover plate 76 in which the supply connection 77 is formed. The cover plate 76 is optional and may be dispensed with if the cross section of the supply connection 77 of the distributor head 7 is equal to the cross section of the outlet port 47 of the coal bunker 42 .
Such a variant is illustrated in FIG. 3 as a distributor head 7 ′. Identical elements are given the same reference symbols as in the embodiment illustrated in FIG. 2 . The collecting chamber 72 ′ is open upwardly. It can be seen that a plurality of radial baffle plates 79 are arranged in the collecting chamber 72 ′. They extend over half the height of the collecting chamber 72 ′ in the exemplary embodiment illustrated, but may also be higher or lower. They serve for swirling in a directed manner a flow circulating tangentially in the collecting chamber 72 ′, in order to achieve better intermixing. Of course, the baffle plates 79 may also be provided in the embodiment, illustrated in FIG. 2 , having a cover plate 76 .
What can also be seen in FIG. 3 is a cone 71 as a centrally arranged displacement body. Its surface area delimits with the peripheral wall 73 an annular slot 70 . This not only forms a direct flow connection between the ports 74 , but imparts a tangential component to the flow in the common collecting chamber 72 ′. This tangential component is reinforced by the baffle plates 79 and improves the intermixing in the common collecting chamber 72 ′ and consequently the distribution of the coal to the lance lines 90 connected to the ports 74 . This arrangement is particularly suitable for preventing or for breaking up skeins in the flow.
To further assist the feed and homogenization of the coal through the lance lines 90 , nitrogen supplies 78 are expediently provided on the bottom 75 of the coal distributor 7 . These supply nitrogen gas which serves for loosening and fluidizing the coal in the collecting chamber 72 , in order thereby to transport it more uniformly through the lance lines 90 to the nozzles 91 .
Further, in each case an optional individual line control unit 8 is arranged on the lance lines 90 . This comprises a quantity sensor 80 which acts on an actuating valve 82 via a compact control unit 81 . The actuating valve 82 regulates the supply of nitrogen supplied via a delivery line 83 into the individual line 90 . The individual line control units 8 of the various lance lines 90 may operate independently or be synchronized by a common control apparatus (not illustrated). They are designed, by means of a regulatable supply of nitrogen, to set finely the throughflow of coal through the lance line 90 .
The arrangement functions as follows. Ground coal is introduced via the line 3 into the pressure vessel 4 via the connection 43 . Segregation takes place in the pressure vessel 4 , the coal falling into the lower region designed as a coal bunker 42 and accumulating there. It has proved appropriate to design the coal bunker 42 such that it allows a filling height for the coal of at least one meter, advantageously even more. The nitrogen gas used for supplying the coal via the line 3 collects in the gas space 41 . It can be discharged from the latter in a controlled way via the pressure regulating device 5 . For this purpose, the filter 51 is preferably designed to be resistant to pressure pulses, in order to compensate pressure surges during the supply of the coal or the adjustment of the regulating valve 52 . Further, optionally, nitrogen may additionally be supplied to the gas space 41 via the actuating valve 56 . The pressure regulating device 5 is operated via the control device 59 such that, even in the case of fluctuating mass flow of the coal supplied via the supply line 3 , the pressure and density in the pressure vessel 4 are kept largely constant, specifically at a value which is sufficient for further transport to the blast furnace 99 . What is achieved thereby is that the same pressure difference takes effect over all the lance lines 90 which are in operation. To be precise, the pressure required for further transport does not correspond exactly to the pressure in the gas space 41 , but to the pressure, increased by the amount of the static pressure of the coal in the coal bunker 42 and the collecting chamber 72 , in the common collecting chamber 72 , level with the ports 74 .
The height of the coal in the coal bunker 42 is determined by the control device by means of the weight sensors 58 ′. The control is designed to determine from a weight increase or weight decrease the filling level and consequently differences between the coal mass flows delivered and conveyed away. The aim, in this case, is to keep the filling level as constant as possible. In the event of the switch-off or failure of individual lance lines 90 or in the event of fluctuations of the mass flow supplied via the line 3 , changes in the filling height in the pressure vessel 4 may occur. Owing to the separate pressure control, however, the pressure difference with respect to the blast furnace 99 remains unchanged, and therefore the mass flows through the lance lines 90 remain constant. By virtue of the constancy thus achieved with regard to pressure and density, the coal passes uniformly out of the coal bunker 41 into the collecting chamber 72 , surrounded by a common wall, of the distributor head 7 , a uniform distribution of the coal to the lance lines 90 being achieved by means of the common collecting chamber 72 .
For a further increase in the uniformity of coal distribution into the lance lines 90 , the individual line control units 8 may be provided. As described above, by means of the quantity sensor 80 , they detect the quantity conveyed through the line and, to adapt this quantity, can conduct additional nitrogen via the regulating valve 83 . As a result, a highly uniform supply of coal to the various nozzles 91 is achieved. | A solids distributor for injection plants includes a collecting chamber having a plurality of lance lines leading away from the chamber. The chamber has a supply connection for a solid to be distributed and is surrounded by a common wall in which a plurality of ports is formed. The lance lines are connected to the ports, and an annular gap is formed in front of the ports and along the common wall. A pressure vessel is arranged geodetically above the collecting chamber, the lower part of the pressure vessel being designed as a bunker, having an outlet providing a direct and continuous junction to the supply connection and an upper part designed as a gas space. The collecting chamber may include a central displacement body which forms the annular gap with the common wall and which may be an upwardly tapering cone which projects out of the collecting chamber. | 5 |
FIELD OF THE INVENTION
[0001] This invention relates to improvements in preventing heat- and moisture-shrink problems in specific polypropylene tape fibers. Such fibers are basically manufactured through the initial production of polypropylene films or tubes which are then slit into very thin, though flat (and having very high cross sectional aspect ratios) tape fibers thereafter. Such fibers (and thus the initial films and/or tubes) require the presence of certain compounds that quickly and effectively provide rigidity to the target polypropylene tape fiber after heat-setting. Generally, these compounds include any structure that nucleates polymer crystals within the target polypropylene after exposure to sufficient heat to melt the initial pelletized polymer and allowing such an oriented polymer to cool. The compounds must nucleate polymer crystals at a higher temperature than the target polypropylene without the nucleating agent during cooling. In such a manner, the “rigidifying” nucleator compounds provide nucleation sites for polypropylene crystal growth. Subsequent to slitting the initial film and/or tube, the fiber is then exposed to sufficient heat to grow the crystalline network, thus holding the fiber in a desired position. The preferred “rigidifying” compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as sodium benzoate, certain sodium and lithium phosphate salts (such as sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11). Specific methods of manufacture of such inventive tape fibers, as well as fabric articles made therefrom, are also encompassed within this invention.
BACKGROUND OF THE PRIOR ART
[0002] Polypropylene tape fibers are utilized in various end-uses, including carpet backings, scrim fabrics, and other fabrics for article reinforcement or dimensional stability purposes. Unfortunately, prior applications utilizing standard polypropylene tape fibers have suffered from relatively high shrinkage rates, due primarily to the tape fiber constituents. Heat, moisture, and other environmental factors all contribute to shrinkage possibilities of the tape fibers (and yarns made therefrom), thereby causing a residual effect of shrinkage within the article itself. Thus, although such polypropylene fibers are highly desired in such end-uses as carpet backings, unfortunately, shrinkage causes highly undesirable warping or rippling of the final carpet product. Or, alternatively, the production methods of forming carpets (such as, for example, carpet tiles) compensate for expected high shrinkage, thereby resulting in generation of waste materials, or, at least, the loss of relatively expensive amounts of finished carpet material due to expected shrinkage of the carpet itself, all the result of the shrinkage rates exhibited by the carpet backing fibers themselves. Furthermore, such previously manufactured and practiced tape fibers suffer from relatively low tensile strengths. For scrim fabrics (such as in roofing articles, asphalt reinforcements, and the like), such shrinkage rate problems are of great importance as well to impart the best overall reinforcement capabilities to the target article and permitting the reinforced article to remain flat. Utilization of much more expensive polyesters and polyamides as constituent fibers has constituted the only alternative methods to such problematic high shrinkage, low tensile strength tape fibers in the past (for both carpet backings and scrim applications).
[0003] There has been a continued desire to utilize such polypropylene tape (high aspect ratio) fibers in various different products (as alluded to above), ranging from apparel to carpet backings (as well as carpet pile fabrics) to reinforcement fabrics, and so on. Such polypropylene tape fibers exhibit excellent strength characteristics and do not easily degrade or erode when exposed to certain “destructive” chemicals. However, even with such impressive and beneficial properties and an abundance of polypropylene, which is relatively inexpensive to manufacture and readily available as a petroleum refinery byproduct, such fibers are not widely utilized in products that are exposed to relatively high temperatures during use, cleaning, and the like. This is due primarily to the aforementioned high and generally non-uniform heat- and moisture-shrink characteristics exhibited by typical polypropylene tape fibers. Such fibers are not heat stable and when exposed to standard temperatures (such as 150° C. and 130° C. temperatures), the shrinkage range from about 2% (in boiling water) to about 3-4% (for hot air exposure) to 5-6% (for higher temperature hot air). These extremely high and varied shrink rates thus render the utilization and processability of highly desirable polypropylene fibers very low, particularly for end-uses that require heat stability (such as carpet pile, carpet backings, molded pieces, and the like).
[0004] Past uses of polypropylene tape fibers within carpet backings have resulted in the necessity of estimating nonuniform shrinkage rates for final products and thus to basically expect the loss of a certain amount of product during such manufacturing and/or further treatment. For example, after a tufted fiber component is first attached to its primary carpet backing component for dimensional stability during printing, if such a step is desired to impart patterns of color or overall uniform colors to the target tufted substrate. After printing, a drying step is required to set the colors in place and reduce potential bleeding therefrom. The temperatures required for such a printing step (e.g., 130° C. and above) are generated within a heated area, generally, attached to the printing assembly. At such high temperatures, typical polypropylene tape fiber-containing backings exhibit the aforementioned high shrink rates (e.g., between 2-4% on average). Such shrinkage unfortunately dominates the dimensional configuration of the printed tufted substrate as well and thus dictates the ultimate dimensions of the overall product prior to attachment of a secondary backing. Such a secondary backing is thus typically cut to a size in relation to the expected size of the tufted component/primary backing article. Nonuniformity in shrinkage, as well as the need to provide differently sized secondary backings to the primary and tufted components thus evince the need for low-shrink polypropylene tape fiber primary carpet backings. With essentially zero shrinkage capability, the reliable selection of a uniform, proper size for the secondary backing would be a clear aid in reducing waste and cost in the manufacture of such carpets.
[0005] If printing is not desired, there still exist potential problems in relation to high-shrink tape fiber primary backing fabrics, namely the instance whereupon a latex adhesive is required to attach the remaining secondary backing components (as well as other components) to the tufted substrate/primary backing article. Drying is still a requirement to effectuate quick setting of such an adhesive. Upon exposure to sufficiently high temperatures, the sandwiched polypropylene tape fiber-containing primary backing will undergo a certain level of shrinkage, thereby potentially causing buckling of the ultimate product (or other problems associated with differing sizes of component parts within such a carpet article).
[0006] To date, there has been no simple solution to such problems, at least that provides substantially the same tensile strength exhibited by such higher-shrink tape fibers. Some ideas for improving upon the shrink rate characteristics of non-tape polypropylene fibers have included narrowing and controlling the molecular weight distribution of the polypropylene components themselves in each fiber or mechanically working the target fibers prior to and during heat-setting. Unfortunately, molecular weight control is extremely difficult to accomplish initially, and has only provided the above-listed shrink rates (which are still too high for widespread utilization within the fabric industry). Furthermore, the utilization of very high heat-setting temperatures during mechanical treatment has, in most instances, resulted in the loss of good hand and feel to the subject fibers. Another solution to this problem is preshrinking the fibers, which involves winding the fiber on a crushable paper package, allowing the fiber to sit in the oven and shrink for long times, (crushing the paper package), and then rewinding on a package acceptable for further processing. This process, while yielding an acceptable yarn, is expensive, making the resulting fiber uncompetitive as compared to polyester and nylon fibers. As a result, there has not been any teaching or disclosure within the pertinent prior art providing any heat- and/or moisture-shrink improvements in polypropylene fiber technology. Additionally, it has been found that these limited shrink-rate improvement procedures for non-tape fibers do not transfer to tape fibers to provide any substantial low-shrink benefits.
[0007] As noted above, the main concern with this invention is the production of low-shrink polypropylene tape fibers. For the purpose of this invention, the term “tape fiber” or fibers is intended to encompass a monofilament fiber exhibiting a cross sectional aspect ratio of at least 2:1, and therefore is a relatively wide and flat fiber. As noted above, such a tape fiber is generally produced through the initial creation of a film and/or tube of polypropylene from which the desired fibers are then slit (thereby according the desired flat configuration through such a slitting procedure with the slitting means, such as blades, situated at substantially uniform distances from each other during the actual slitting process to provide substantially uniform aspect ratios for the target fibers themselves).
DESCRIPTION OF THE INVENTION
[0008] It is thus an object of the invention to provide improved shrink rates without appreciably reducing tensile strengths for polypropylene tape fibers. A further object of the invention is to provide a class of additives that, in a range of concentrations, will provide low shrinkage and/or higher tensile strength levels for such inventive tape fibers (and yarns made therefrom). A further object of the invention is to provide a carpet made with a polypropylene backing exhibiting very low heat shrinkage rates. Another object of the invention is to provide a specific method for the production of nucleator-containing polypropylene tape fibers permitting the ultimate production of such low-shrink, high tensile strength, fabrics therewith. Yet another object of the invention is to provide a carpet article having a backing comprising a majority of relatively inexpensive polypropylene fibers that exhibits very low shrinkage.
[0009] Accordingly, this invention encompasses a polypropylene tape fiber comprising at least 10 ppm of a nucleator compound, and exhibiting a tensile strength of at least 3 grams/denier. Also encompassed within this invention is a polypropylene tape fiber comprising at least 10 ppm of a nucleator compound and exhibiting a shrinkage rate after exposure to 150° C. hot air of at most 2%, wherein said fiber further exhibits a tensile strength of at least 2.5 grams/denier. Also, this invention encompasses a polypropylene tape fiber exhibiting an x-ray scattering pattern such that the center of the scattering peak is at most 0.4 degrees. Certain yarns and fabric articles comprising such inventive fibers are also encompassed within this invention. Of particular concern is a carpet article having a top side and a bottom side, wherein a fiber substrate of either tufted fiber, berber fiber, or like type is attached to said top side and a backing comprising a majority of poylpropylene fibers wherein said fibers comprise at least 10 ppm of a nucleator compound, is attached to said bottom side. Preferably, such a carpet article exhibits very low shrinkage rates on par with those noted above.
[0010] Furthermore, this invention also concerns a method of producing such fibers comprising the sequential steps of a) extruding a heated formulation of polypropylene comprising at most about 2000 ppm, preferably at most about 1500 ppm, more preferably at most about 1000 ppm, and most preferably below about 800 ppm, of a nucleator compound into a film or tube; b) immediately quenching the film or tube of step “a” to a temperature which prevents orientation of polypropylene crystals therein; c) slitting said film or tube with cutting means oriented longitudinally to said film or tube thereby to produce individual tape fibers therefrom; d) mechanically drawing said individual tape fibers at a draw ratio of at least 5:1 while exposing said fibers to a temperature of at between 250 and 360° C., preferably between 260 and 330° C., and most preferably between 270 and 300° C. , thereby permitting crystal orientation of the polypropylene therein. Preferably, step “b” will be performed at a temperature of at most 95° C. and at least about 5° C., preferably between 5 and 60° C., and most preferably between 10 and 40° C. (or as close to room temperature as possible for a liquid through simply allowing the bath to acclimate itself to an environment at a temperature of about 25-30° C.). Again, such a temperature is needed to ensure that the component polymer (being polypropylene, and possibly other polymeric components, such as polyethylene, and the like, as structural enhancement additives therein that do not appreciably affect the shrinkage characteristics thereof) does not exhibit orientation of crystals. Upon the heated draw step, such orientation is effectuated which has now been determined to provide the necessary rigidification of the target tape fibers and thus to increase the strength and modulus of such fibers. The drawing speed to line speed ratio should exceed at least five times that of the rate of movement of the film to the cutting means. Preferably, such a drawing speed is at from 400-700 feet/minute, while the prior speed of the film to the cutting means from about 50-400 feet/minute, with the drawing speed ratio between the two areas being from about 3:1 to about 10:1, and is discussed in greater detail below, as is the preferred method itself. The final heat-setting temperature is necessary to “lock” the polypropylene crystalline structure in place after extruding and drawing. Such a heat-setting step generally lasts for a portion of a second, up to potentially a couple of minutes (i.e., from about {fraction (1/10)} th of a second, preferably about ½ of a second, up to about 3 minutes, preferably greater than ½ of a second). The heat-setting temperature must be well in excess of the drawing temperature and must be at least 265° F., more preferably at least about 290° F., and most preferably at least about 300° F. (and as high as 380° F.). The term “mechanically drawing” is intended to encompass any number of procedures which basically involve placing an extensional force on fibers in order to elongate the polymer therein. Such a procedure may be accomplished with any number of apparatus, including, without limitation, godet rolls, nip rolls, steam cans, hot or cold gaseous jets (air or steam), and other like mechanical means.
[0011] Such tape yarns may also be produced through extruding individual fibers of high aspect ratio and of a sufficient size, thereby followed by drawing and heatsetting steps in order to attain such low shrinkage rate properties. All shrinkage values discussed as they pertain to the inventive fibers and methods of making thereof correspond to exposure times for each test (hot air and boiling water) of about 5 minutes. The heat-shrinkage at about 150° C. in hot air is, as noted above, at most 2.0% for the inventive fiber; preferably, this heat-shrinkage is at most 1%; more preferably at most 0.5%; and most preferably at most 0.1%. Also, the amount of nucleating agent present within the inventive fiber is at least 10 ppm; preferably this amount is at least 50 ppm; and most preferably is at least 100 ppm, up to a preferred maximum (for tensile strength retention) of about 700-800 ppm. Any amount within this range should suffice to provide the desired shrinkage rates after heat-setting of the fiber itself; again, however, excessive amounts (e.g., above about 2,000 ppm) should be avoided, primarily due to costs and tensile strength problems.
[0012] However, in the event that very high processing speeds (either initial drawing speeds or heatsetting drawing speeds, as examples) are practiced for very quick fibers production, higher amounts of nucleator compound(s) may be desired, up to about 2000 ppm, for instance, in order to provide faster crystallization rates at such high drawing speeds.
[0013] Furthermore, it has now been determined that the presence of between 10 and 1000 ppm of a nucleator compound within polypropylene fibers for incorporation within primary (or secondary) carpet backing provides the highly desirable result of no appreciable shrinkage of the backing, as well as of a tufted substrate/backing composite, or even of an entire carpet article. Thus, any low-shrink carpet backing component comprising a majority of polypropylene fibers including such nucleator compound (in the requisite amounts, preferably between 200 and 800 ppm, and most preferably between about 400 and 700 ppm), provides the necessary low shrinkage properties. Fibers and/or yarns of the inventive tape type, as well as polypropylene staple, multifilament, and monofilament, types, are available in such capacity for such improved, low-shrink carpet articles.
[0014] The term “polypropylene” is intended to encompass any polymeric composition comprising propylene monomers, either alone or in mixture or copolymer with other randomly selected and oriented polyolefins, dienes, or other monomers (such as ethylene, butylene, and the like). Such a term also encompasses any different configuration and arrangement of the constituent monomers (such as syndiotactic, isotactic, and the like). Thus, the term as applied to fibers is intended to encompass actual long strands, tapes, threads, and the like, of drawn polymer. The polypropylene may be of any standard melt flow (by testing); however, standard fiber grade polypropylene resins possess ranges of Melt Flow Indices between about 2 and 50. Contrary to standard plaques, containers, sheets, and the like (such as taught within U.S. Pat. No. 4,016,118 to Hamada et al., for example), fibers clearly differ in structure since they must exhibit a length that far exceeds its cross-sectional area (such, for example, its diameter for round fibers). Fibers are extruded and drawn; articles are blow-molded or injection molded, to name two alternative production methods. Also, the crystalline morphology of polypropylene within fibers is different than that of standard articles, plaques, sheets, and the like. For instance, the dpf of such polypropylene fibers is at most about 5000; whereas the dpf of these other articles is much greater. Polypropylene articles generally exhibit spherulitic crystals while fibers exhibit elongated, extended crystal structures. Thus, there is a great difference in structure between fibers and polypropylene articles such that any predictions made for spherulitic particles (crystals) of nucleated polypropylene do not provide any basis for determining the effectiveness of such nucleators as additives within polypropylene fibers.
[0015] The terms “nucleators”, “nucleator compound(s)”, “nucleating agent”, and “nucleating agents” are intended to generally encompass, singularly or in combination, any additive to polypropylene that produces nucleation sites for polypropylene crystals from transition from its molten state to a solid, cooled structure. Hence, since the polypropylene composition (including nucleator compounds) must be molten to eventually extrude the fiber itself, the nucleator compound will provide such nucleation sites upon cooling of the polypropylene from its molten state. The only way in which such compounds provide the necessary nucleation sites is if such sites form prior to polypropylene recrystallization itself. Thus, any compound that exhibits such a beneficial effect and property is included within this definition. Such nucleator compounds more specifically include dibenzylidene sorbitol types, including, without limitation, dibenzylidene sorbitol (DBS), monomethyldibenzylidene sorbitol, such as 1,3:2,4-bis(p-methylbenzylidene) sorbitol (p-MDBS), dimethyl dibenzylidene sorbitol, such as 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (3,4-DMDBS); other compounds of this type include, again, without limitation, sodium benzoate, NA-11, and the like. The concentration of such nucleating agents (in total) within the target polypropylene fiber is at least 10 ppm, preferably at least 50 ppm. Thus, from about 10 to about 2000 ppm, preferably from about 50 ppm to about 1500 ppm, and most preferably from about 100 ppm to about 800 ppm. Furthermore, such inventive tape fibers must be produced by basically the slitting of extruded films or tubes as outlined above.
[0016] Also, without being limited by any specific scientific theory, it appears that the shrink-reducing nucleators which perform the best are those which exhibit relatively high solubility within the propylene itself. Thus, compounds which are readily soluble, such as 1,3:2,4-bis(p-methylbenzylidene) sorbitol provides the lowest shrinkage rate for the desired polypropylene fibers. The DBS derivative compounds are considered the best shrink-reducing nucleators within this invention due to the low crystalline sizes produced by such compounds. Other nucleators, such as NA-11, also provide acceptable low-shrink characteristics to the target polypropylene fiber and thus are considered as potential nucleator compound additives within this invention. Basically, the selection criteria required of such nucleator compounds are particle sizes (the lower the better for ease in handling, mixing, and incorporation with the target resin), particle dispersability within the target resin (to provide the most effective nucleation properties), and nucleating temperature (e.g., crystallization temperature, determined for resin samples through differential scanning calorimetry analysis of molten nucleated resins), the higher such a temperature, the better.
[0017] It has been determined that the nucleator compounds that exhibit good solubility in the target molten polypropylene resins (and thus are liquid in nature during that stage in the fiber-production process) provide effective low-shrink characteristics. Thus, low substituted DBS compounds (including DBS, p-MDBS) appear to provide fewer manufacturing issues as well as lower shrink properties within the finished polypropylene fibers themselves. Although p-MDBS is preferred, however, any of the above-mentioned nucleators may be utilized within this invention as long as the x-ray scattering measurements are met or the low shrink requirements are achieved through utilization of such compounds. Mixtures of such nucleators may also be used during processing in order to provide such low-shrink properties as well as possible organoleptic improvements, facilitation of processing, or cost.
[0018] In addition to those compounds noted above, sodium benzoate and NA-11 are well known as nucleating agents for standard polypropylene compositions (such as the aforementioned plaques, containers, films, sheets, and the like) and exhibit excellent recrystallization temperatures and very quick injection molding cycle times for those purposes. The dibenzylidene sorbitol types exhibit the same types of properties as well as excellent clarity within such standard polypropylene forms (plaques, sheets, etc.). For the purposes of this invention, it has been found that the dibenzylidene sorbitol types are preferred as nucleator compounds within the target polypropylene fibers.
[0019] The closest prior art references teach the addition of nucleator compounds to general polypropylene compositions (such as in U.S. Pat. No. 4,016,118, referenced above). However, some teachings include the utilization of certain DBS compounds within limited portions of fibers in a multicomponent polypropylene textile structure. For example, U.S. Pat. Nos. 5,798,167 to Connor et al. and 5,811,045 to Pike, both teach the addition of DBS compounds to polypropylene in fiber form; however, there are vital differences between those disclosures and the present invention. For example, both patents require the aforementioned multicomponent structures of fibers. Thus, even with DBS compounds in some polypropylene fiber components within each fiber type, the shrink rate for each is dominated by the other polypropylene fiber components which do not have the benefit of the nucleating agent. Also, there are no lamellae that give a long period (as measured by small-angle X-ray scattering) thicker than 20 nm formed within the polypropylene fibers due to the lack of a post-heatsetting step being performed. Again, these thick lamellae provide the desired inventive higher heat-shrink fiber. Also of importance is the fact that, for instance, Connor et al. require a nonwoven polypropylene fabric laminate containing a DBS additive situated around a polypropylene internal fabric layer which contained no nucleating agent additive. The internal layer, being polypropylene without the aid of a nucleating agent additive, dictates the shrink rate for this structure. Furthermore, the patentees do not expose their yarns and fibers to heat-setting procedures in order to permanently configure the crystalline fiber structures of the yarns themselves as low-shrink is not their objective.
[0020] In addition, Spruiell, et al, Journal of Applied Polvmer Science , Vol. 62, pp. 1965-75 (1996), reveal using a nucleating agent, MDBS, at 0.1%, to increase the nucleation rate during spinning, but not for tape fibers. However, after crystallizing and drawing the fiber, Spruiell et al. do not expose the nucleated fiber to any heat, which is necessary to impart the very best shrinkage properties, therefore the shrinkage of their fibers was similar to conventional polypropylene fibers without a nucleating agent additive.
[0021] Of particular interest and which has been determined to be of primary importance in the production of such inventive low-shrink polypropylene fibers, is the discovery that, at the very least, the presence of nucleating agent within heat-set polypropylene fibers (as discussed herein), provides high long period measurements for the crystalline lamellae of the polypropylene itself. This discovery is best explained by the following:
[0022] Polymers, when crystallized from a melt under dynamic temperature and stress conditions, first supercool and then crystallize with the crystallization rate dependent on the number of nucleation sites, and the growth rate of the polymer, which are both in turn related to the thermal and mechanical working that the polymer is subjected to as it cools. These processes are particularly complex in a normal fiber drawing line. The results of this complex crystallization, however, can be measured using small angle x-ray scattering (SAXS), with the measured SAXS long period representative of an average crystallization temperature. A higher SAXS long period corresponds to thicker lamellae (which are the plate-like polymer crystals characteristic of semi-crystalline polymers like PP), and which is evidenced by a SAXS peak centered at a lower scattering angle than for comparative unnucleated polypropylene tape fibers. The higher the crystallization temperature of the average crystal, the thicker the measured SAXS long period will be. Further, higher SAXS long periods are characteristic of more thermally stable polymeric crystals. Crystals with shorter SAXS long periods will “melt”, or relax and recrystallize into new, thicker crystals, at a lower temperature than those with higher SAXS long periods. Crystals with higher SAXS long periods remain stable to higher temperatures, requiring more heat to destabilize the crystalline structure.
[0023] In highly oriented polymeric samples such as fibers, those with higher SAXS long periods will remain stable to higher temperatures. Thus the shrinkage, which is a normal effect of the relaxation of the highly oriented polymeric samples, remains low to higher temperatures than in those highly oriented polymeric samples with lower SAXS long periods. In this invention, as is evident from these measurements, the nucleating additive is used in conjunction with a thermal treatment to create fibers exhibiting a center of the SAXS scattering peak of at most 0.4 degrees, which corresponds to thicker lamellae that in turn are very stable and exhibit low shrinkage up to very high temperatures.
[0024] Furthermore, such fibers may also be colored to provide other aesthetic features for the end user. Thus, the fibers may also comprise coloring agents, such as, for example, pigments, with fixing agents for lightfastness purposes. For this reason, it is desirable to utilize nucleating agents that do not impart visible color or colors to the target fibers. Other additives may also be present, including antistatic agents, brightening compounds, clarifying agents, antioxidants, antimicrobials (preferably silver-based ion-exchange compounds, such as ALPHASAN® antimicrobials available from Milliken & Company), UV stabilizers, fillers, and the like. Furthermore, any fabrics made from such inventive fibers may be, without limitation, woven, knit, non-woven, in-laid scrim, any combination thereof, and the like. Additionally, such fabrics may include fibers other than the inventive polypropylene fibers, including, without limitation, natural fibers, such as cotton, wool, abaca, hemp, ramie, and the like; synthetic fibers, such as polyesters, polyamides, polyaramids, other polyolefins (including non-low-shrink polypropylene), polylactic acids, and the like; inorganic fibers such as glass, boron-containing fibers, and the like; and any blends thereof.
[0025] Of particular interest as end-uses for such inventive tape fibers are primary carpet backings and thus carpets comprising such backing components. These are described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWING
[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate a potentially preferred embodiment of producing the inventive low-shrink polypropylene fibers and together with the description serve to explain the principles of the invention wherein:
[0027] [0027]FIG. 1 is a schematic of the potentially preferred method of producing low-shrink polypropylene tape fibers.
[0028] [0028]FIG. 2 is a side view of a preferred carpet article comprising the inventive fibers within a backing.
DETAILED DESCRIPTION OF THE DRAWING AND OF THE PREFERRED EMBODIMENT
[0029] [0029]FIG. 1 depicts the non-limiting preferred procedure followed in producing the inventive low-shrink polypropylene tape fibers. The entire fiber production assembly 10 comprises a mixing manifold 11 for the incorporation of molten polymer and additives (such as the aforementioned nucleator compound) which then move into an extruder 12 . The extruded polymer is then passed through a metering pump 14 to a die assembly 16 , whereupon the film 17 is produced. The film 17 then immediately moves to a quenching bath 18 comprising a liquid, such as water, and the like, set at a temperature from 5 to 95° C. (here, preferably, about room temperature). The drawing speed of the film at this point is dictated by draw rolls and tensionsing rolls 20 , 22 , 24 , 26 , 28 set at a speed of about 100 feet/minute, preferably, although the speed could be anywhere from about 20 feet/minute to about 200 feet/minute, as long as the initial drawing speed is at most about ⅕ th that of the heat-draw speed later in the procedure. The quenched film 19 should not exhibit any appreciable crystal orientation of the polymer therein for further processing. Sanding rolls 30 , 31 , 32 , 33 , 34 , 35 , may be optionally utilized for delustering of the film, if desired. The quenched film 19 then moves into a cutting area 36 with a plurality of fixed knives 38 spaced at any distance apart desired. Preferably, such knives 38 are spaced a distance determined by the equation of the square root of the draw speed multiplied by the final width of the target fibers (thus, with a draw ratio of 5:1 and a final width of about 3 mm, the blade gap measurements should be about 6.7 mm). Upon slitting the quenched film 19 into fibers 40 , such fibers are moved uniformly through a series of nip and tensioning rolls 42 , 43 , 44 , 45 prior to being drawn into a high temperature oven 46 set at a temperature level of between about 280 and 350° C., in this instance about 310° C., at a rate as noted above, at least 5 times that of the initial drawing speed. Such an increased drawing speed is effectuated by a series of heated drawing rolls 48 , 50 (at temperatures of about 360-400° F. each) over which the now crystal-oriented fibers 54 are passed. A last tensioning roll 52 leads to a spool (not illustrated) for winding of the finished tape fibers 54 .
[0030] Turning to FIG. 2, then, an inventive carpet article 110 is shown comprising a pile layer 112 comprising tufted fibers 114 tufted through a fabric substrate 113 (which could be woven, knit, or non-woven in structure and comprise any type of natural fibers, such as cotton, and the like, or synthetic fibers, such as polyamide, and the like; preferably, it is a woven substrate comprising polyamide fibers), and embedded within an adhesive layer 115 , to which is attached a primary backing layer 116 comprising the inventive fibers, and a secondary backing layer 118 (which may be a fabric, such as a felt, or resin, such as polyvinyl chloride other like compound; preferably, it is felt in nature) to provide increased dimensional stability thereto. The primary backing layer 116 is adhered to both the pile layer 112 and the secondary backing layer 118 to form the desired carpet article 110 . The inventive primary backing layer 116 , comprising such low-shrink polypropylene tape fibers, thus accords the desired low-shrink characteristics to the entire carpet article 110 itself. Of course, alternative configurations and arrangements of backing layers (such as an increase or decrease in the number required) as well as types of fibers (such as berber, short pile, and the like) within the pile layer may be employed, as well as myriad other variations common within the carpet art and industry.
INVENTIVE FIBER AND YARN PRODUCTION
[0031] The following non-limiting examples are indicative of the preferred embodiment of this invention:
EXAMPLE 1
[0032] The carpet backing slit film fibers were made on the standard production equipment as described above at a drawing rate of 600 ft/min as follows: A 3.5-3.8 melt flow homopolymer polypropylene resin (P4G32-050, from Huntsman) was blended with an additive concentrate consisting of 10% 4-methyl-DBS and 90% 4 MFI homopolypropylene resin. The blending ratio was changed to adjust the final additive level, as shown in the table below. This mixture, consisting of PP resin and the additive, was extruded on a single screw extruder through a film dye approximately 72 inches wide. The PP flow was adjusted to give a final tape thickness of approximately 0.002 inches. The molten film was quenched in room temperature (about 25° C.) water, then transferred by rollers to a battery of knives, which cut it into parallel strips. An approximately 100 ppm concentration of 4-methyl-DBS (aka, p-methyl-DBS) was utilized. Upon production, the film appeared clear. The film, having been slit into strips, was run across three large rolls all running at 110 ft/min, and then into an oven, approximately 14 ft long and set a temperature of about 330° F., where it was drawn. After leaving the oven, the film strips were transferred to three more rolls, running at speeds of 600, 500 and 500 ft/min, respectively. The first two rolls were heated by hot oil to temperatures of 367° F. These film strips were then traversed to winders where they were individually wound up. These final film strips are thus referred to as the polypropylene tape fibers.
[0033] Several tape fibers were made in this manner, adjusting the concentrated additive-PP mixture level to adjust the final additive level. These tape fibers were tested for tensile properties on an MTS Sintech 10/G instrument. They were also tested for shrinkage at 150° C. and 155° C. in hot air by measuring 5 10″ strips, exposing them in an oven for 5 minutes at the aforementioned temperatures, and then removing the strips and measuring the resultant length. Shrinkage was calculated as the average shrinkage of the five strips in relation to the initial lengths thereof. The concentration level of 4-methyl-DBS in the tape fiber was also measured by gas chromatograhy. All of these results are reported in the table below for different nucleator compound levels in different fibers (with the denier measured at Xg/9000 m, and the shrinkage rates measured at 150° C. in hot air).
TABLE 1 Inventive Tape Fiber Yarn Measurements Nucleator Yarn # Level Denier Shrinkage Elongation Modulus Tenacity Toughness 1(Control) 0 ppm 1218 0.8% 44% 14.07 g/d 3.11 g/d 0.87 g/d 2(Control) 0 ppm 1202 0.6% 44% 14.62 g/d 3.22 g/d 0.97 g/d 3 82.9 ppm 1220 0.1% 45% 14.46 g/d 3.18 g/d 0.91 g/d 4 159.9 ppm 1196 0.1% 45% 14.62 g/d 3.24 g/d 0.92 g/d 5 196.2 ppm 1206 0.1% 44% 14.82 g/d 3.00 g/d 0.86 g/d 6 265.6 ppm 1175 0.1% 45% 14.22 g/d 3.13 g/d 0.95 g/d 7 345.4 ppm 1166 0.8% 47% 14.79 g/d 3.14 g/d 0.94 g/d 8 473.9 ppm 1135 0.4% 47% 14.28 g/d 3.03 g/d 0.94 g/d 9 549.1 ppm 1144 0.4% 44% 14.05 g/d 2.99 g/d 0.89 g/d 10 637.7 ppm 1090 1.0% 43% 14.81 g/d 3.13 g/d 0.93 g/d 11 739.0 ppm 1081 0.8% 45% 14.62 g/d 2.98 g/d 0.92 g/d
[0034] Thus, the inventive fibers provided excellent low shrinkage rates and very good physical characteristics as well.
[0035] X-ray Scattering Analysis
[0036] The long period spacing of several of the above yarns was tested by small angle x-ray scattering (SAXS). The small angle x-ray scattering data was collected on a Bruker AXS (Madison, Wis.) Hi-Star multi-wire detector placed at a distance of 105 cm from the sample in an Anton-Paar vacuum chamber where the chamber was evacuated to a pressure of not more than 100 mTorr. X-rays (λ=1.54178 Å) were generated with a MacScience rotating anode (40 kV, 40 mA) and focused through three pinholes to a size of 0.2 mm. The entire system (generator, detector, beampath, sample holder, and software) is commercially available as a single unit from Bruker AXS. The detector was calibrated per manufacturer recommendation using a sample of silver behenate.
[0037] A typical data collection was conducted as follows. To prepare the sample, the yarn was wrapped around a 3 mm brass tube with a 2 mm hole drilled in it, and then the tube was placed in an Anton-Paar vacuum sample chamber on the x-ray equipment such that the yarn was exposed to the x-ray beam through the hole. The path length of the x-ray beam through the sample was between 2-3 mm. The sample chamber and beam path was evacuated to less than 100 mTorr and the sample was exposed to the X-ray beam for one hour. Two-dimensional data frames were collected by the detector and unwarped automatically by the system software. The data were smoothed within the system software using a 2-pixel convolution prior to integration. To obtain the intensity scattering data [I(q)] as a function of scattering angle [2θ] the data were integrated over φ with the manufacturer's software set to give a 2θ range of 0.2°-2.5° in increments of 0.01° using the method of bin summation.
[0038] The data was collected upon exposure to such high temperatures for one-half hour, and subtracting the baseline obtained by taking similar data with no tape fiber sample in place. The center of the scattering peak is obtained by integrating a 60 degree wedge above the sample, said wedge centered on the axis that defines the tape fiber direction. The peak is defined in two ways: either as the position of maximum counts near the center of the peak, or as the average of the positions of the left half maximum and the right half maximum of the peaks. The position of the maximum counts and the center are shown in the table below.
TABLE 2 SAXS Data for Inventive Tape Fibers Maximum Max position Center Sample Number counts degrees degrees 0 261 0.275 0.2875 1 264.9 0.255 0.26 2 286.6 0.255 0.27 3 278 0.25 0.255 4 266.7 0.255 0.2675 5 260.2 0.255 0.2675 6 238.8 0.255 0.2725 7 233.5 0.255 0.2625 8 221.3 0.255 0.265 9 233.4 0.255 0.2575 10 237.4 0.255 0.2575
[0039] Yarns of the tape fibers above were then woven into a primary carpet backing component for carpet tiles. Such tape fibers were made with knives set to cut the tape to different widths, such that yarns of both approximately 1100 and 600 denier measurements were made. The 600 denier yarns were warped at 24 yarns/inch and a full width of about 168 inches. These warped yarns were then woven with the wider, 1100 denier yarns on a rapier loom at approximately 12 picks per inch to provide a backing substrate. Upon attachment of such a backing (18 inches wide) to a tufted substrate (also 18 inches wide), followed by printing with liquid colorants and dyes of the surface opposite the backing itself, the resultant composite was then exposed to drying temperatures (about 130° C.). The complete composite subsequently exhibited no appreciable modification of the dimensions thereof. A comparative polypropylene tape fiber-containing primary backing exhibited shrinkage rate of about 4-5%, thereby reducing the dimensions of the comparative tufted substrate/primary backing composite by a similar amount. Thus, it is apparent that the inventive tape fibers are substantial improvements over the typical, traditional, state of the art polypropylene tape fibers utilized today.
[0040] There are, of course, many alternative embodiments and modifications of the present invention which are intended to be included within the spirit and scope of the following claims. | Improvements in preventing heat- and moisture-shrink problems in specific polypropylene tape fibers are provided. Such fibers are basically manufactured through the initial production of polypropylene films or tubes which are then slit into very thin, though flat (and having very high cross sectional aspect ratios) tape fibers thereafter. Such fibers (and thus the initial films and/or tubes) require the presence of certain compounds that quickly and effectively provide rigidity to the target polypropylene tape fiber after beat-setting. Generally, these compounds include any structure that nucleates polymer crystals within the target polypropylene after exposure to sufficient heat to melt the initial pelletized polymer and upon allowing such a melt to cool. The compounds must nucleate polymer crystals at a higher temperature than the target polypropylene without the nucleating agent during cooling. In such a manner, the “rigidifying” nucleator compounds provide nucleation sites for polypropylene crystal growth. Upon slitting of the initial film and/or tube, the fiber is then exposed to sufficient heat to grow the crystalline network, thus holding the fiber in a desired position. The preferred “rigidifying” compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as sodium benzoate, certain sodium and lithium phosphate salts (such as sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11). Specific methods of manufacture of such inventive tape fibers, as well as fabric articles made therefrom, are also encompassed within this invention. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the joining of flat woven fabrics to render them endless. More particularly, the invention relates to joining papermakers wet press felt base fabrics to render them endless. Most particularly, the present invention relates to joining flat woven papermakers wet press felt base fabrics having crimped machine direction yarns.
2. Description of the Prior Art
It is known to join a flat woven fabric in order to render it endless. In the earliest fabrics, the woven yarns were generally natural fibers, such as cotton, wool and combinations thereof. Due to the nature of the natural fiber, the joined area receives some of its mechanical strength from the natural resistance of the fibers pulling past each other and additional strength from the fiber migration which took place during fulling of the felt. The join area in these fabrics are generally quite large and may extend over several feet.
With the advent of synthetic monofiliments which have more regular and smoother surface characteristics, thee was a tremendous reduction in the mechanical strength attributable to fiber movement resistance. Similarly, the practice of fulling was no longer part of the finishing operations for the press felt. Accordingly, the mechanical strength generally associated with fiber entanglement as a result of fulling was no longer a major factor in seam strength.
As a result of the above, the art developed a number of joining techniques to produce the required mechanical strength. One of the principle drawbacks of the prior art join was the large joining area which was still necessary to accomplish mechanical strength. It is believed that the need for a large join area is directly related to the weave construction of the prior art fabrics wherein the crimp was generally in the cross machine direction yarns and a number of cross machine direction yarns had to be involved in order to accomplish the joining structure. Although the synthetic monofiliments generally maintain their crimp memory, lack of crimp in the machine or running direction of the fabric necessitated large joining areas. The length of the fabric seam is generally determined by the same strength which is necessary to maintain the fabric under the running load or tension associated with fabric operation. It is not uncommon to have a fabric running load of 20 pli (pounds per lineal inch). Under this load, the typical press felt fabric would have a minimum seam length of about ten (10) inches.
In view of the above, efforts were undertaken to reduce the size of the join area and to improve the uniformity in the join area. Along with improved uniformity and reduced size, the art desired a join which had improved resiliency to compression in the nip area of the papermaking machine. It was found that the use of machine direction crimp in the flat woven fabric produced a crimp pattern which accurately reflected the fabric weave. Once the woven fabric was heat set, the machine direction yarns have a fixed memory of the crimp pattern which means that the join area may be rewoven in the precise pattern of the original flat woven fabric. As a result, the endless fabric will have substantially the identical pattern, caliper and air permeability through its length.
The warp yarns are crimped as a result of the inner weaving with cross machine direction yarns and heat setting. The yarn memory for this crimp permits reweaving of the fabric to join the fabric ends to achieve mechanical strength based on the initial crimp patterns established during the weaving. In this manner, the resultant fabric join area establishes essentially the same weave pattern as if the pattern had been woven endless in the first instance. However, fabrics according to the present invention can include much higher machine direction yarn counts then would be available with a similar fabric which had been woven endless.
SUMMARY OF THE INVENTION
The present invention provides a papermakers wet press felt having a flat woven base fabric with the crimped yarns oriented in the lengthwise or machine direction. Orientation of the crimp in the machine direction lends itself to an analysis of the crimps per square inch based upon crimp length and warps end count. Utilizing the crimp per square inch figure, it is possible to establish the approximate length of the join in the machine direction.
Based on the above analysis of crimps per square inch, the machine direction length of the join area is approximated by the equation: approximate join length equals 500 divided by the crimps per square inch in the repeat pattern of the base fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation which illustrates a single layer plain weave fabric having crimped machine yarns which are joined; the cross machine direction yarns are shown in section.
FIG. 2 is similar to FIG. 1 and illustrates a two over-one under fabric.
FIG. 3 is similar to FIG. 1 and illustrates a two over-two under fabric.
FIG. 4 is similar to FIG. 1 and illustrates the invention in a multi-ply fabric.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although specific weave patterns and constructions have been selected for illustration in the drawings and the following description refers in specific terms to those drawings, it will be understood that the description is not intended to limit the scope of the invention to the specific weave patterns and constructions shown.
With reference to FIG. 1, there is shown a papermakers wet press felt 10, which includes a batt layer 20 on the sheet or paper carrying surface, and a batt layer 22 on the machine side surface of the felt. The felt 10 also includes a flat woven base fabric 30. Base fabric 30 is comprised of a plurality of cross machine direction yarns 32, which are interwoven in the usual fashion with a plurality of machine direction yarns. Through the use of the join shown in FIG. 1, a flat woven fabric is rendered endless. In order to render the fabric endless, the machine direction yarns 34 and 36, from a first end of the flat woven fabric, have been rewoven or backwoven so as to abut machine direction yarns 38 and 40 of what previously constituted the other end of the flat woven fabric. The techniques for rendering fabrics endless in this method will be known to the skill in the art. Likewise, those skilled in the art will recognize that the yarn abutments 42 and 44 should be staggered throughout the join area and spaced from each other. The length of the join area is determined as the maximum machine direction distance between two sets of yarn abutments.
In the present application to papermakers wet press felts, it is preferred that the join areas 42 and 44 be completed on the face or sheet side 20 of the felt 10. Since the potential does exist for the end of a joined yarn to back out of the fabric, it is preferred that the join take place at the face or sheet side of the fabric. In case a yarn does back out of the construction, the loose end of the yarn will then be disposed away from the product and on the machine side of the press felt 10.
As noted above, the techniques for joining the fabric endless are known in the prior art. In addition, it is believed that some single layer forming fabrics have been rendered endless through the use of backweaving techniques employing machine direction yarns which were crimped during the flat weaving process. However, those fabrics were not subjected to nip pressure, which can have a highly detrimental effect upon the integrity of the join area.
Still with reference to FIG. 1, it will be recognized by those skilled in the art that the illustrated construction is a plain weave. In such a plain weave, the machine direction yarns will form a crimp 50 after interweaving with two cross machine direction yarns. Accordingly, the crimp 50 has a length which includes two knuckles, 52 and 54, which form on opposite planes or surfaces of the base fabric 30. The length of the crimp 50 is measured between the points 56 and 58 where the yarn intersects the center line through the base fabric 30.
In addition to considerations regarding the number of crimps per inch in the machine direction yarns, it is necessary to consider the number of ends or machine direction yarns which are adjacent to each other in one inch of cross machine direction width. Based upon this relationship, and full consideration of the weave construction, it is possible to establish the join area which will be necessary for a given construction. In order to more fully understand the invention, reference is made to the following example.
In a sample fabric, which was a single layer plain weave fabric having fifteen picks per inch of 0.019" diameter monofilament, each inch of machine direction yarn interacted with approximately fifteen picks or cross machine direction yarns. In appreciation of the fact that each crimp requires two knuckles, a plain weave of this type yielded approximately 7.5 crimps per inch of machine direction yarn. The machine direction yarn count was approximately thirty, six ends per inch of 0.019" diameter monofilaments. Based on these yarn counts, each square inch of fabric yields approximately 270 crimps. With this fabric construction, it was found that a suitable join could be established across the width of the fabric over a maximum machine direction length of 4.5 inches.
With reference to FIGS. 2 and 3, it can be seen that as the construction of the base fabric 30 is modified to include longer floats on one or both surfaces, the length of crimp 50 increases. Accordingly, the number of crimps available per inch of machine direction yarn is reduced. In the construction of FIG. 2 of over two and under one, there are approximately 5 crimps per inch. In the construction of FIG. 3 which is an over two, under two construction, there are approximately 4 crimps per inch. As can be appreciated by those skilled in the art, the reduced number of interlacings without any associated increase in yarn counts, translates into reduced fabric stability. Accordingly, it is expected that the length of the join area will need to be increased for construction where the pick and/or end counts are the same as that used in the illustration with respect to FIG. 1. As the pick and/or end count is increased the crimps per square inch will increase, and the length of the join area will again be reduced.
In determining the length of the join area, it has been found that the approximate join length in the machine direction can be approximated within plus or minus three percent by the equation, approximate join length equals 500 divided by the crimps per square inch. As noted previously, the crimps per square inch must be calculated based upon the weave construction and the number of ends in the repeat. The number 500 is a base line which has been arrived at based upon analysis that indicates that a plain weave fabric having 270 crimps per square inch will require a minimum 1.86 inch join length in order to provide an acceptable strength level in the join area. However, it appears that a minimum 2 inch join length is necessary to provide yarn distribution and a proper work area. While a minimum 2 inch join may provide acceptable strength, a layer length is preferred in order to provide additional safeguards against joint failures.
With respect to FIG. 4, there is shown a multi-layer construction. The multi-layer construction of FIG. 4 is fully described in U.S. Pat. 4,892,781. The constructions of U.S. Pat. No. 4,892,781 lend themselves to joining in accordance with the invention and a description of those constructions is incorporated herein as if fully set forth, with respect to FIG. 4, it will be noted that the crimp length extends from the middle of the float as indicated 60 to the point of transition as indicated at 62. As will be appreciated by those skilled in the art, the increased crimp length means that there will be generally less crimps available per inch of a duplex or multiply fabric. However, such duplex or multiply fabrics often incorporate higher end counts and tighter weaved constructions. In any event, the approximation equation set forth above applies equally to such multiple constructions. Likewise, it can be seen from FIG. 4 that the join area may be on the machine side of the fabric. | A seam for a papermakers wet press felt having a flat woven base fabric with the crimped yarns oriented in a lengthwise or machine direction. Orientation of the crimp in the machine direction lends itself to an analysis of the crimps per square inch based upon the crimp length and warp end count. Utilizing the crimps per square inch figure, it is possible to establish the approximate minimum length of the join in the machine direction. The machine direction length, in inches, of the join area is approximated by the equation: approximate joined length equals 500 divided by the crimps per square inch in the repeat pattern of the woven base fabric. | 3 |
This Application is a file wrapper continuation of U.S. application Ser. No. 08/165,058, filed Dec. 9, 1993, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to internal drive shafts used in conjunction with vascular catheters for rotating a work performing element. More particularly, the present invention relates to a flexible composite drive shaft.
2. Previous Art
Atherectomy procedures using various catheter instruments for imaging and surgically removing portions of stenoses in the human vascular system are well known. Examples of surgical procedures are provided in U.S. Pat. No. Re 33,569 to Gifford et al., U.S. Pat. No. 5,071,425 to Gifford, and U.S. Pat. No. 5,092,873 to Simpson et al. These patents generally teach a housing having a window connected to the distal end of a catheter, a cutter enclosed within the housing and exposed through the window for removing a portion of the stenosis, a lumen within the catheter for passage of the cutter, and a drive shaft for connecting the cutter to a proximal drive coupling means.
Stenotic tissue takes a number of different forms. Some stenoses are soft and flexible. Soft stenoses typically require a catheter to have a drive shaft with an acceptable degree of axial stiffness for accurately moving a work performing element with very sharp cutting edges to precisely cut small, flexible flaps of tissue. Other stenoses take the form of hard, calcified deposits. Hard, calcified deposits typically require a catheter having a drive shaft with acceptable axial stiffness to apply considerable axial force with a sharp, durable cutter against the deposits.
Vascular catheters may have rotating ultrasonic imaging devices attached at the distal end for imaging a region of a blood vessel having an atheroma before and after an interventional treatment. Such catheters frequently utilize a flexible drive cable or shaft in order to transmit a rotational drive force from a driving device such as a motor located at the proximal end of the catheter to a work performing element located at the distal end.
Ultrasonic imaging is used to improve identification of the nature, extent and location of the stenoses during surgery. Ultrasonic imaging is also used to determine the method of treatment and the resultant effect. The use of such imaging is exemplified in U.S. Pat. application Ser. No. 08/051,521 by Milo, et al. herein incorporated by reference. As taught in this patent application, ultrasonic energy is generated by a transducer located at the distal end of, or within a vascular catheter. The transducer is manipulated rotationally and axially to a desired position by a drive shaft means to sweep a ultrasonic signal in a desired pattern.
Ultrasonic energy reflected from the different layers of the blood vessel, including any stenosis or occlusion present, is processed by a display processor and the result used to display an image or profile of the interior of the vessel. The display of the image is typically presented on a monitor connected to the display processor. The resulting image is typically a picture showing a cross sectional representation of the vessel looking outward from the center of the vessel. The picture may be a cross section showing the radial topography of the vessel perpendicular to the axis, or a cross section showing a longitudinal topography in the axial direction of the vessel.
The position of the transducer in the blood vessel is critical to the accuracy of the image as the representation of the interior of the vessel. The rotational and axial transducer position in the blood vessel is typically inferred from the rotational and axial position of encoders mounted on the proximal end of the drive shaft. Any variation in position of the transducer at the distal end of the drive shaft with respect to the proximal end will result in error in the image as a representation of the shape of the actual blood vessel. A rotationally and axially stiff drive shaft is needed to give an accurate image representation.
It is also important that the drive shaft provide high torsional strength and stiffness to minimize variation in the rotational velocity of the imaging element on the distal end of the catheter. Fluctuations of rotational velocity of the imaging element cause distortion in the resulting image display.
The rotational motion of the work performing element at the distal end of the catheter is provided by the torsional force, i.e., torque transmitted from a motor drive unit (MDU) through the drive shaft. The drive shaft must have sufficient torsional stiffness in order to deliver adequate rotational force to the work performing element along the relatively long path through the catheter connecting the drive means to the work performing element.
It is particularly important that the drive shaft provide a high torsional stiffness such that the distal end of the drive shaft and the proximal end of the drive shaft turn nearly together without appreciable rotational lag. Rotational lag is a difference between the angular displacement of one end of the drive shaft with respect to the other. The rotational lag between the distal and proximal ends of the drive shaft under load is commonly referred to as "wind up" which it experiences due to the high length to diameter aspect ratio.
In addition to rotation, it is frequently desirable to be able to translate the work performing element in an axial direction within the catheter, preferably simply by pushing or pulling on the proximal end of the drive shaft.
It is additionally important that the drive shaft be capable of a high degree of lateral bending without "kinking" or fracturing. This attribute is required to negotiate the tortuous passages of the vascular system without causing the drive shaft to bind or seize up in the catheter, or possibly shatter due to material fatigue, potentially causing damage to the patient.
The attributes of lateral flexibility and torsional strength are simultaneously required while the drive shaft is rotating, frequently at high rpm while also being translated in an axial direction.
It is well known in the art to use drive cables consisting of solid wires, wound springs or braided cables. Typically, compromises must be made to achieve acceptable degrees of torsional stiffness, bending flexibility and axial stiffness to minimize excessive windup, easily negotiate tight curves and accurately position the working element in the catheter. For some applications, e.g. ultrasonic imaging, the accuracy of angular position is important for providing an accurate representation of the layers of the vessel walls being studied. Excessive windup and rotational velocity fluctuation is particularly important to minimize in these cases.
The drive shaft used in atherectomy procedures as described above includes an elongated member, usually a narrow diameter cylindrical member. This elongated member rotationally connects a rotating means, such as a mechanical coupler located at the proximal end of the catheter, with the work performing element located at the distal end of the catheter.
Various means to provide flexible drive shaft structures have been employed. U.S. Pat. No. 5,108,411, discloses a vascular catheter having a flexible drive shaft extending through a central lumen. The shaft is formed of essentially two distinct proximal and distal sections having different construction and different bending and torsional flexibility. The embodiment is disclosed as having a proximal section of solid 304V stainless steel and a distal section of 304V stainless steel helical wound springs. These two distinct sections have different torsional and flexural characteristics. An elastomeric coating over the two sections is provided to reduce friction and enhance rotation of the drive shaft within the catheter lumen.
Atherectomy drive shafts of solid wire are also known. An example is disclosed in Willard, U.S. Pat. No. 5,085,662. This discloses a drive shaft having a core of solid wire of 304 stainless steel to provide axial stiffness, surrounded by a set of smaller wires of lower ultimate strength and higher flexibility. Another approach is to provide a central core wire having a taper at the distal end encapsulated by a 12 to 16 wire braid of 0.002 to 0.003 in. stainless steel wire. These braids are composed of multiple strands or filaments of finer wire. These structures have bending characteristics which are primarily limited by the properties of the central core wire materials selected, i.e. stainless steel. There is no disclosure of cooperation between the polymeric coating material, the helical wound members and the central core member.
It is therefore desirable to provide improved drive shafts for vascular catheters having rotationally driven work performing elements at their distal end. Particularly, it is desirable to provide drive shafts which are sufficiently flexible to negotiate the tortuous passages through which catheters must pass, drive shafts with sufficient torsional stiffness to minimize rotational wind up, and sufficient flexural stiffness to avoid seizing and binding of the drive shaft in the catheter, and sufficient axial stiffness to provide accurate axial positioning. It is further desirable to provide drive shafts which are capable of negotiating the tight bending radii and narrow curvature within the vascular system while operating at high rotational speed without suffering from the effects of premature failure due to material fatigue. It is additionally desirable to provide drive shafts having very narrow diameters in order to allow catheters to be constructed which can enter very small diameter blood vessels.
What is needed is drive shaft structures for vascular catheters which allows freedom in providing drive shafts having torque transmission characteristics which can be optimized for different requirements. It is also desirable to provide drive shaft structures for vascular catheters having axial force transmission characteristics which can additionally be optimized for different requirements.
There is also a need for drive shaft structures for vascular catheters having high tolerance to tight bending requirements. It is also desirable to provide drive shaft structures for vascular catheters having low failure probability due to material fatigue at high rotational speeds.
There is also a need for flexible drive shafts which minimize wind-up while retaining acceptable rotational stiffness and lateral flexibility.
SUMMARY OF THE INVENTION
In general, it is an object in accordance with this invention, to provide a flexible composite drive shaft having sufficient rotational stiffness to transmit a rotational drive force from a driving device such as a motor located at the proximal end of the catheter to a work performing element located at the distal end.
In addition, it is an object in accordance with this invention to provide a flexible composite drive shaft having suitable axial stiffness to translate and position the work performing element accurately in an axial direction within the catheter.
In addition, it is an object in accordance with this invention to provide a composite drive shaft having suitable rotational stiffness and consistent in rotational velocity of the work performing and/or imaging element.
In addition, it is an object in accordance with this invention to provide that the composite drive shaft be capable of a high degree of lateral bending without failure.
In accordance with the above objects and those that will be mentioned and will become apparent below, the composite drive shaft adapted for use with a biological catheter in accordance with this invention, comprises:
an elongated core made from shape memory alloy, the core defining a cylindrical substrate having an outer surface, the core extending from the proximal end of the drive shaft through at least a substantial portion of the drive shaft, and a reinforcing member for reinforcing the torsional strength of the composite drive shaft, the reinforcing member surrounding the core having a first end attached to one end of the core, the reinforcing member having the other end attached to the opposite end of the core, whereby the combination of the core shape memory alloy which supports the reinforcing member provides improved torsional stiffness and improved axial stiffness to the drive shaft while retaining high lateral bending flexibility around the tortuous paths of the vascular system.
The improved axial stiffness of the composite drive shaft over that of conventional helical spring members, is provided by the shape memory alloy core. The improved rotational stiffness of the composite drive shaft over that of conventional helical spring members is provided by the combination of the support of the shape memory alloy core and the spring member. The high degree of lateral flexibility of the composite drive shaft is provided by the highly elastic nature of the shape memory alloy in combination with the reinforcing spring member.
A preferred embodiment of the composite drive shaft has a tubular shape memory alloy core surrounded by a reinforcing spring member which constitutes the first 2/3 of the drive shaft from the proximal end. The balance of the composite drive shaft is a conventional helical wound member connecting to the work performing element.
The attachment of the reinforcing member to the core may be made at one point at each end location. The attachment may alternately be made in multiple points at each end location, a sector of a circular region, or in some other suitable shape at each end location.
In a preferred embodiment of this invention, the core and the surrounding reinforcing member are coated with a polymeric coating which impregnates the interstices between the reinforcing member and the core.
In a preferred embodiment, the composite drive shaft is made from a shape memory alloy which is selected from one of the group of a first alloy constituting essentially nickel-titanium, a second alloy constituting essentially copper-zinc-aluminum and a third alloy constituting essentially copper-aluminum-nickel.
In an additional preferred embodiment the reinforcing member is a helical wound member wrapped around the outer surface of the core, the helical wound member including at least one filamentary element.
In a preferred embodiment of the composite drive shaft, the polymeric coating and impregnation within the interstices between the core and the reinforcing member acts to distribute forces such that the torsional stiffness of the composite is synergistically enhanced without significantly reducing the lateral flexibility. The combination of the three elements results in a composite drive shaft that exhibits the increased torsional stiffness characteristic of the material of the reinforcing member and the axial stiffness characteristics of the material of the core. The shape of the reinforcing member combined with the highly elastic nature of the shape memory alloy core material results in a composite drive shaft that has a very flexible lateral bending characteristic.
An additional preferred embodiment according to this invention has a helical wound member provided with a set of multiple strands or filamentary elements wound simultaneously. The strands are wound to be in contact with the core. The core acts as a rigid foundation or substrate for the strands which results in torsional forces being supported by the material of the strands.
The reinforcing member of one embodiment in accordance with this invention is a double wound member comprising a first helical wound member and an oppositely wound second helical member. The first member is comprised of one or more filamentary elements adjacent to the outer surface of the core and having a first winding direction and the second helical wound member is comprised of one or more filamentary elements defining a second winding direction.
In an additional embodiment of this invention, the second helical wound member is disposed outside the first helical wound member. The winding of the second member is such that the second member is in contact with the first member. The rotation of the composite drive shaft in use is such that the outside diameter of the first helical wound member tends to expand and the second member outside diameter tends to decrease. The result is an increase in the torsional stiffness characteristic of the composite drive shaft above that of the core material alone.
The first helical wound member in another embodiment in accordance with this invention is intertwined and braided with the second helical wound member over the length of the core of the composite drive shaft. The braided structure provides torsional stiffness characteristics essentially equal in both directions of rotation of the composite drive shaft.
In another embodiment, the end of the core and the end of the reinforcing member at the second attachment point are angularly displaced relative to the first attachment point. The end of the core and the end of the reinforcing member are also angularly displaced oppositely to each other. The angular displacements of the core end and the reinforcing member end are held in place before forming the second attachment point. The core and reinforcing member are then released and allowed to come to an equilibrium rotational position.
The core relaxes from a maximum rotational strain in one direction toward zero strain. The spring member absorbs rotational strain until the combination reaches equilibrium. The core and the reinforcing member are thereby preloaded with opposed torsional strain. The direction of preloaded torsional strain in the core is selected to be in opposition to the direction of torsional strain added during use. The torsional strain in use thereby subtracts from the preloaded torsional stain in the core.
The opposed direction of preloaded torsional strain and the in use torsional strain thereby cause an increase in the allowable maximum total angular displacement of the core, in use, before reaching an absolute maximum angular strain in the core.
The preloading direction for the above embodiment is selected to be in an angular direction to bring the reinforcing member in contact with the core after the second attachment is made and the core is released. The reinforcing member is thereby caused to tighten down on the core. This results in a higher torsional stiffness characteristic for the composite drive shaft.
In another embodiment, the displacement of the end of the core and the end of the reinforcing member and the attachment are first positioned as described above.
The opposed direction of preloaded torsional strain and the in use torsional strain thereby cause an increase in the allowable maximum total angular displacement of the core, in use, before reaching an absolute maximum angular stress in the core.
In addition, the direction of preloading is in such a direction as to bring the reinforcing member away from contact with the core during use. The composite drive shaft of this embodiment will have an increased resistance to failure due to additional angular displacement between proximal and distal ends during use.
In another embodiment, the reinforcing member includes a double wound spring having an inner winding and an outer winding. The two windings are wound in opposite directions. The inner winding is wound to be in contact with the core and the outer winding is wound to be in contact with the inner winding. The windings are impregnated with a polymeric coating of polyethylene. The winding direction and preloading in this embodiment is such that the torsional strain in the core is nearly equal to the beginning of a first superelastic region of the core in a first direction of angular displacement, whereby a torsional load placed in opposition to the preloaded strain will cause the core to traverse the full span of elastic strain from the first superelastic region to a second superelastic region in a second rotational direction opposite to the first direction of angular displacement. This structure provides a significant increase in the amount of rotation with a high torsional stiffness coefficient.
Suitable treatment of the polymeric coating such as heating, causes it to penetrate the interstices between the reinforcing member and the core. This penetration makes contact of the polymeric material with the reinforcing member and the outer surface of the core; whereby coupling forces between the reinforcing member and the core are more uniformly distributed. The coating filled interstices of this embodiment combined with the high elasticity of the selected core material causes an increase in the amount of angular displacement between the proximal and distal ends of the drive shaft before failure and an increase in the torsional stiffness coefficient of the composite drive shaft.
It is an advantage of this invention to provide an atherectomy apparatus having a flexible composite drive shaft having sufficient rotational stiffness to accurately transmit rotational drive force from the proximal end of the catheter to a work performing element located at the distal end.
It is an additional advantage of this invention to provide an apparatus capable of accurately translating and positioning a work performing element within a catheter.
It is an additional advantage of this invention to provide an atherectomy apparatus capable of operating with improved consistency in angular velocity of a work performing and/or imaging element.
It is an additional advantage of this invention to provide a composite drive shaft having improved resistance to failure due to material fatigue at high rotational speed around tortuous bends.
BRIEF DESCRIPTION OF THE DRAWING
For a further understanding of the objects and advantages of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in which like parts are given like reference numerals and wherein:
FIG. 1 is a schematic partial perspective view of a composite drive shaft in accordance with this invention.
FIG. 2 is a schematic partial side view of a composite drive shaft having a single spring member in accordance with this invention.
FIG. 3 is a schematic partial side view of a second embodiment having a double wound spring member in accordance with this invention.
FIG. 4 is a schematic partial side view of a third embodiment having a braided spring member in accordance with this invention.
FIG. 5 is a cross section of FIG. 2 taken along line 5--5 in the direction of the arrows.
FIG. 6 is a cross section of FIG. 3 taken along line 6--6 in the direction of the arrows.
FIG. 7 is a cross section of FIG. 4 taken along line 7--7 in the direction of the arrows.
FIG. 8 is a cross section of an alternate embodiment of FIG. 2 having a spacing between the core and the inner winding.
FIG. 9 is a cross section of an alternate embodiment of FIG. 3 having a spacing between the core and the inner winding.
FIG. 10 is a graph of torsional stiffness coefficient vs angular displacement for the embodiment of FIG. 2.
FIG. 11 is a graph of torsional stiffness coefficient vs angular displacement for an alternate embodiment of FIG. 2 with preloaded torsional strain.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described with reference to FIGS. 1 and 2 wherein the composite drive shaft in accordance with this invention is shown generally by the numeral 20. The composite drive shaft 20 includes an elastic core 22, having an outer surface 24, a reinforcing member 28 surrounding the core 22, a polymeric coating 34 surrounding the member 28 and a drive coupling means 38 connected to the proximal end of the core 22. The distal end of the core 22 is connected to a work performing element (not shown). The material for core 22 is selected from the group of shape memory alloys. The preferred shape memory alloy is one of an alloy consisting essentially of nickel-titanium, or an alloy consisting essentially of copper-aluminum-nickel or an alloy consisting essentially of copper-zinc-aluminum. A preferred shape memory alloy is nickel-titanium. Shape memory alloys of nickel-titanium in tubing form may be obtained from Advanced Cardiovascular Systems, Inc, Santa Clara, Calif.
The reinforcing member 28 surrounds the core 22 from the proximal end of the drive shaft 20 to the distal end of the drive shaft 20. The reinforcing member 28 is attached to the core 22 at least at two points. The attachment is made by solder, welding, epoxy or other suitable method. With reference to FIG. 2, there is shown a first attachment point 30 at one end of the composite drive shaft 20. A second attachment is made at a second attachment point 32 at the opposite end of the drive shaft 20. The attachment of the core 22 and the reinforcing member 28 has the effect of combining the axial and torsional characteristics of the core 22 and the reinforcing member 28. The result is such that the composite drive shaft 20 behavior is improved as will be explained below with reference to FIGS. 2-4 and FIG. 10.
The elastic core 22 is generally an elongated cylinder. The reinforcing member 28 is wound helically around the core 22 in the form of a spring.
As illustrated in FIGS. 1-4, a coating 34 of polymeric material such as polyethylene, or the like is applied to the core 22 and reinforcing member 28. The coating 34 provides two functions. First, the coating 34 forms a smooth, surface for providing low surface friction for sliding in a catheter (not shown). Second, the coating 34 is applied to penetrate and impregnate the interstices 36 depicted in FIGS. 5, 6, and 7 between the reinforcement member 28 and the core 22. This penetration and impregnation binds the core 22 and member 28 more firmly together.
In a preferred embodiment shown in FIG. 2, the core 22 is shown as a tube 23 having a lumen 26 therethrough from a proximal end to a distal end. The lumen 26 acts as a passageway for introducing other instruments, e.g. a guide wire, electrical leads and the like, from the proximal end of the composite drive shaft 20 through the slipperylumen 26. The lumen 26 may also be used as a passageway for transport of atheroma material removed by the working element (not shown) on the distal end of the composite drive shaft 20 to a removing means (not shown) at the proximal end of the composite drive shaft 20.
The composite drive shaft 20 has the core 22 made from a material selected from the shape memory group of materials described above. The preferred material is an alloy of nickel-titanium having a composition of about 50% nickel and 50% titanium.
The core 22 is comprised of a thin walled tube 23 of nickel-titanium with an outside diameter in the range from 0.01 to 0.125 inches in diameter, having a wall thickness between 0.001 to 0.020 inches. The preferred dimension for this embodiment is 0.024 in. outside diameter, with a wall thickness of approximately 0.003 inch.
The core 22 is surrounded by a reinforcing helical wound spring member 40. The spring member 40 includes filament strands 44 in the form of continuous coils. The spring member 40 extends from the proximal end of the composite drive shaft 20 to the distal end of drive shaft 20. The reinforcing helical winding member 40 is a single winding of a high strength spring material such as 304 stainless steel. The preferred spring material is a flat wound wire having a 0.003 in. by 0.008 in. rectangular cross section. Spring windings having cross sections in the range of 0.001 by 0.001 to 0.010 by 0.010 inches are used to optimize other performance features.
The spring winding member 40 provides additional torsional strength to the composite drive shaft 20. The winding 40 combines with the core 22 for transmission of torsional forces as will be described below. The low bending resistance of the helical winding 40 cooperates with the high elasticity of the shape memory tube 22 to allow the composite drive shaft 20 to negotiate the sharp curves of the vascular system in a suitable manner.
The FIGS. 1-4 are shown with the reinforcing helical wound member 40 as having successive turns wound in contact. This method of winding will cause the turns of the winding 40 to assume an angle Θ relative to the axis of the core 22 as indicated in FIG. 2. The angle Θ defines the "pick" angle. The successive turns of member 40 may be spaced apart thereby decreasing the pick angle from a maximum. The pick angle of the member 40 can be selected to optimize torsional and axial stiffness characteristics of the composite drive shaft 20 for a given set of material parameters.
The core 22 provides suitably high axial strength and resistance to elongation and compression in the axial direction of the composite drive shaft 20 relative to the helical wound reinforcing member 40. The increased axial strength of the core 23 relative to the helical winding 40 provides more accurate axial positioning for the purpose of placing and moving the work performing element (not shown) than a helical winding alone.
The work performing element is positioned by pushing or pulling on the composite drive shaft 20 at the drive coupling means 38 at the proximal end of the composite drive shaft 20. During the axial movement of the drive shaft 20, the highly elastic flexural nature of the nickel-titanium core 22 and winding allows suitable bending and flexing of the composite drive shaft 20 around the tortuous passages associated with the vascular system.
The composite drive shaft 20 of this invention provides improved consistency of angular velocity and position over previous art helical wound drive shafts.
As shown in FIG. 2, a coating 34 of polymeric material such as polyethylene, or the like is applied to the core 22 and reinforcing member 40. The coating 34 provides two functions. First, the coating 34 forms a smooth, slippery surface for providing low surface friction for sliding in a catheter (not shown). Second, the coating 34 is applied to penetrate and impregnate the interstices 36 depicted in FIGS. 5, 6, and 7 between the reinforcement member 40 and the core 22. This penetration and impregnation tends to binds the core 22 and member 40 together more completely.
In the embodiment shown in FIG. 2, when rotation is initiated, the coils 44 of the reinforcing member 40 are not all in intimate contact with the nickel-titanium tube 23. Therefore the torsional stiffness coefficient for the composite drive shaft 20 is primarily determined by the properties of the core 22 and the polymeric coating 42.
As used herein, torsional stiffness coefficient (K t ) is defined as:
K t =τL/θ, where
τ= applied torque on drive cable section (in-lb)
L= length of shaft section in., and
θ= angle of wind up over length (radians)
As rotation continues the spring coils 44 begin to engage the tube 23. The spring coils 44 are constrained by contact with the outside diameter of the tube 23 from contracting. As a result the torsional stiffness coefficient K t of the composite drive shaft 20 increases to a value associated with the material of the spring member 40. When the coils 44 are fully engaged on the tube 23, the torsional stiffness of the composite drive shaft remains constant at a higher level.
This higher level continues with further rotation until the squeezing force of the spring coils 44 and the torsional stress on the tube 23 causes the material of tube 23 to enter a region of the stress-strain behavior of the selected materials known as the superelastic region. This region is characterized by lower strength and increased deformation. The lowered strength of the tube 23 material no longer permits supporting the coils 44 of the member 40 in torsion wherein Kt of the composite drive shaft 20 decreases.
FIG. 10 illustrates the graph of K t versus angular displacement for a 10.5 in. long sample of an embodiment of the composite drive shaft 20 depicted in FIG. 2. The embodiment has a nickel-titanium tube 23 of 0.018 inch inner diameter and 0.024 inch outer diameter. The tube 23 has a single winding 40 of a 0.004 by 0.008 inch flat wound 304 SS forming the spring coils 44. The coils 44 are attached at each end of the composite drive shaft 20 by attachment points 30 and 32 respectively. The coils 44 are impregnated with a coating of polyethylene 34.
It is the cooperation of the spring member 40, the tube 23 and the polyethylene 34 which gives increased torsional stiffness for a given degree of bending stiffness.
Another embodiment in accordance with this invention is shown in FIG. 3. The core 22 has a tubular member 23 having a lumen 26 and an outer surface 24. The core 22 has a proximal end connected to a drive coupling means 38 and a distal end connected to a working member (not shown). The reinforcing member 28 includes a first helical member 40 wound in a first winding direction around the tube 23. The reinforcing member 28 includes a second helical member 46 wound in a second winding direction on top of and opposite to the first helical member 40. The helical winding member 40 and 46 are attached to the tube 23 at first attachment points 30, 31 at one end of the composite drive shaft 20 and second attachment points 32, 33 at the opposite end of drive shaft 20.
The direction of rotation of the composite drive shaft 20 in use is such that the outside diameter of the first helical member 40 tends to expand and the outside diameter of the second helical member 46 tends to collapse. This structure gives a combined torsional stiffness coefficient for the composite drive shaft 20 greater than that of the spring members 40, 46 and core 22 alone. The torsional stiffness coefficient for the embodiment shown in FIG. 3 is essentially uniform throughout the length of the composite drive shaft 20, from the proximal end to the distal end of the shaft 20. The value of the uniform torsional stiffness coefficient for this embodiment is about 0.11 in-lb-in per radian. This structure provides a nearly constant torsional stiffness coefficient of 0.11 in-lb-in per radian from 0 to over 10π radians of angular displacement between the drive shaft 20 proximal and distal ends for a 10.5 inch length.
A drive shaft structure consisting of single or double wound springs alone for use as vascular catheter flexible drive shafts is well known in the art. The combination of such springs and a shape memory alloy core material having highly elastic flexural properties for making composite drive shafts is not known in the art and is one of the novel features in accordance with this invention.
Another embodiment of the composite drive shaft 20 in accordance with this invention is depicted with reference to FIG. 2 and cross section FIG. 5. The tube 22 is formed of 0.024 inch outside diameter nickel-titanium with wall thickness 0.003 inch. The spring member 40 is a 0.003 inch by 0.008 inch flat wound quadfilar 304 stainless steel spring wound over the tube 22.
The spring member 40 and tube 23 are coated with a polyethylene sheath 34 of about 0.003 inches thickness and treated such that the polyethylene 34 penetrates the interstices 36 between the spring member 40 and the tube 23.
ALTERNATE EMBODIMENT WITH PRELOADED TORSIONAL STRAIN
With regard to FIG. 2 a preferred embodiment is described herebelow. The tube 23 and spring member 40 of the composite drive shaft 20 are first attached at a first attachment point 30 near one end of the composite drive shaft 20. The tube 23 is then twisted about π/2 radians/inch in a direction opposite to normal use. This causes the shape memory alloy tube to approach the onset of the super elastic region. Tube 23 and spring member 40 are then attached at the second attachment point 32 near the opposite end of the composite drive shaft 20. The tube 23 and the spring member 40 then are released. Tube 23 unwinds, reducing torsional strain within the tube 23, while spring member 40 winds and absorbs torsional strain until they reach a rest position.
This displacement is such that the combined tube 23 and spring member 40 have suitable preloaded, oppositely directed, torsional stress and strain built into the composite drive shaft 20 in a rest position prior to use.
The preferred range of preloaded torsional strain keeps the shape memory alloy material in the linear elastic range prior to the onset of the super elastic range. A preferred value of preloaded strain for the embodiment of FIG. 2 is about π/4 radians/inch of length of the composite drive shaft 20.
The direction of preloading is such that the spring member 40 tends to tighten down onto the tube 23 when the drive shaft 20 is rotated in a direction of normal use. This embodiment provides a torsional stiffness of about 0.075 in-lb-in per radian.
In the preloaded embodiment of FIG. 2, the preloading of the tube 23 and spring member 40 assures that the coils 44 are forced against the core in a rest condition prior to use. At the onset of rotation, the full engagement of the coils 44 with the tube 23 is already effected whereby the torsional stiffness coefficient of the composite drive shaft 20 is increased beyond that of the spring member 40 and tube 23 alone.
Rotation of the preloaded drive shaft 20 in a first direction such that the torsional force on the tube 23 initially decreases, passes through zero and approaches the super elastic region from the other direction. This causes an increase in the amount of rotation needed to move the tube 23 into the superelastic region, whereby the higher torsional stiffness coefficient of the composite drive shaft is effective over a larger angular displacement than an unloaded condition.
The graph of Kt vs rotational displacement for the preloaded embodiment of FIG. 2 is illustrated in FIG. 11. Preloading causes the initial value of Kt at zero angular displacement to be higher than it would be without preloading.
ALTERNATE EMBODIMENT WITH OPPOSITE PRELOADED STRAIN
An alternate embodiment of the composite drive shaft 20 in accordance with this invention has the direction of preloading such that the spring member 40 tends to expand when the composite drive shaft 20 is rotated in the direction of normal use.
ALTERNATE EMBODIMENT WITH BRAIDED WINDINGS
Another embodiment of the composite drive shaft 20 in accordance with this invention is illustrated in FIG. 4 and in cross section in FIG. 7. The embodiment of FIG. 4 provides equal performance in both directions of rotation. A reinforcing member comprises a first helical wound member 47 intertwined and braided with a second helical wound member 49. The first helical wound member 47 is comprised of at least one first filament element 47 wound in a first winding direction. The second helical wound member 49 is comprised of at least one second filament element 49 wound in a second, opposite winding direction. The intertwined and braided helical wound members 47, 49 are disposed between the outer surface of the core 22 and the polymeric coating 34. The helical wound members 47, 49 are attached to the core 22 near the proximal end of the composite drive shaft 20 at attachment points 30,31 and attached near the distal end of the shaft 20 at attachment points 32,33.
Another embodiment in accordance with this invention is illustrated with reference to FIG. 2 and FIG. 8. This embodiment depicts a composite drive shaft 20 having the inner winding member 50 having an inside diameter larger than the outside diameter of the core 22, whereby there is a core-winding spacing 48 formed between the core 22 and the winding member strands 50. This structure is used for applications were it is desired to optimize other characteristics of the composite drive shaft 20.
Another embodiment is shown with reference to FIG. 3 and FIG. 9. This embodiment includes a composite drive shaft 20 having an inner winding member 50 having an inside diameter larger than the outside diameter of the core 22 and a core-winding spacing 48 formed between the core 22 and the winding member strands 50. An outer winding member 56 is wound oppositely to member 40. This structure is also used to optimize the characteristics of the composite drive shaft 20 for applications requiring bidirectional rotation.
While the foregoing detailed description has described several embodiments of the drive shaft in accordance with this invention, it is to be understood that the above description is illustrative only and not limiting of the disclosed invention. It will be appreciated that it would be possible to modify the proportions of the core and reinforcing member relative to the drive shaft length, the spring material, winding directions, number of filamentary elements, filament dimensions, open or closed windings, pick angle, core dimensions, amount and direction of preloading, core temper, composition and transition characteristics, the thickness and material used for coating and impregnation, the amount of penetration of the polymeric coating within the interstices between the windings and the core or whether impregnation is used at all. Using the principles disclosed in accordance with this invention one can predict the torsion characteristics of a drive shaft which includes or excludes various elements within the scope and spirit of this invention. Thus, the invention is to be limited only by the claims as set forth below. | A flexible composite drive shaft used with a flexible vascular atherectomy catheter for connecting a proximal rotating drive member and a distal rotatable working member. The flexible composite drive shaft includes a core of specially selected highly elastic shape memory alloy surrounded by a flexible torsional reinforcing helical wound member and a covering of a smooth polymeric material penetrating the interstices between the wound member and the outer surface of the core. The material of the core, the relative winding direction of the reinforcing member and the direction of angular offset between the reinforcing member and the core are selected to optimize the consistency of the rotational characteristics of the drive shaft in use. The cooperation between the shape memory elastic core, the helical reinforcing member and the interpenetrating polymer provides a composite drive shaft which has improved resistance to kinking and binding failure while traversing tight radii, narrow blood vessel pathways during axial translation and high speed rotational operation. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Provisional Application Serial No. 60/437,070, filed Dec. 30, 2002 and entitled “Electric Downhole Safety Valve,” which is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
FIELD OF THE INVENTION
[0003] The present invention relates generally to downhole safety valves and more particularly to a downhole safety valve that is electrically operated.
BACKGROUND OF THE INVENTION
[0004] The invention relates to a surface controlled subsurface safety valve (SCSSV) for a sub-terranean well and, more particularly, to a safety valve utilizing an electrical actuation mechanism controlled from the surface or by a downhole intelligent controller.
[0005] Oil and gas wells typically employ at least one safety valve that can be actuated to stop or control the flow of fluid through a pipe. These valves are normally positioned downhole to close the bore of the tubing string extending from one or more production zones to the well surface. Safety valves of this type include a spring that biases the valve to a fail-safe mode, such that an interruption in the force acting to keep the valve open will cause the valve to close.
[0006] Conventional downhole safety valves are hydraulically operated. As oil and gas reserves are developed in deepwater, however, the column of fluid needed for hydraulic actuation becomes impractically long. Specifically, the hydrostatic head developed in a conventional hydraulically controlled valve results in high operating pressures and requires an unworkably large failsafe spring.
[0007] Because of the problems with hydraulically controlled safety valves, electrically operated safety valves are an attractive alternative. In addition, intelligent completion systems are being developed that are equipped with a variety of electrically driven flow control devices. Hence, it is currently desirable to provide an all-electric control system and remove the requirement for any hydraulic supply. Electrically controlled downhole safety valves have been developed, but they generally require high power consumption and/or unfavorably large geometry, and are vulnerable to problems with electrical connections to the surface.
[0008] Hence, it remains desirable to provide an electrically operated downhole safety valve that can operate effectively and reliably at deep setting depths, using available power downhole.
SUMMARY OF THE INVENTION
[0009] The present invention provides an electrically operated downhole safety valve that can operate effectively and reliably using available power downhole. In a preferred embodiment, the present system fits into a casing no larger than would be required for a comparable hydraulic unit.
[0010] The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention, and by referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more detailed description of the preferred embodiments of the present invention, reference will now be made to the accompanying drawings, wherein:
[0012] [0012]FIG. 1 is a schematic cross-section of a device constructed in accordance with a preferred embodiment of the present invention, showing the valve in a closed position;
[0013] [0013]FIG. 2 is a schematic cross-section of the device of FIG. 1, showing the valve in a open position;
[0014] [0014]FIG. 3 is a cross-section taken along lines 3 - 3 of FIG. 2; and
[0015] [0015]FIGS. 4 and 5 are cross-sections taken along lines 4 - 4 and 5 - 5 of FIG. 2, showing the restraining mechanism in its de-energized and energized states, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] Referring initially to FIG. 1, a device constructed in accordance with a preferred embodiment of the present invention comprises a generally cylindrical body 10 having a central bore 12 therethrough and a concentric flow tube 50 slidably mounted in bore 12 . Body 10 includes a first end 13 and a second end 14 , and preferably includes female threads 15 at each end. In addition, bore 12 includes a valve receptacle 16 , a spring receptacle 26 , an eccentric gearbox receptacle 36 , and a guide groove 46 , all described in detail below.
[0017] Flow tube 50 comprises a cylindrical tube having a first end 53 and a second end 54 . The outer surface of flow tube 50 includes a first, annular extension 56 spaced a first distance from first end 53 and a second, non-annular extension 58 spaced a further distance from first end 53 . In addition, the outer surface of flow tube 50 includes an outwardly extending follower pin 59 between annular extension 56 and non-annular extension 58 .
[0018] Referring still to FIG. 2 and in particular to bore 12 in body 10 , valve receptacle 16 comprises a first increased diameter portion in bore 12 . Valve receptacle 16 is bounded by a lower, frustoconical shoulder 17 and an upper, annular shoulder 18 . The inside diameter of valve receptacle 16 is greater than the outer diameter of flow tube 50 , creating a chamber 19 therebetween. A closure element 20 is housed in chamber 19 , along with a spring 22 . Closure element 20 is pivotally mounted such that it can pivot about a transverse axis between a closed position, shown in FIG. 1, in which it bears on annular shoulder 18 , and an open position, shown in FIG. 2. In its closed position, closure element 20 preferably substantially obstructs the flow of fluid through bore 12 and in its open position it does not. It will be understood that the closed and open positions need not be completely closed or completely open. In other words, the closed and open positions may be merely relative; namely, the closed position being one in which less fluid is allowed to pass than is allowed in the open position. Spring 22 is preferably mounted between closure element 20 and body 10 such that it bears on closure element and urges it into its closed position. Sprint 22 is shown as a coil spring, but it will be understood that spring 22 can comprise any suitable biasing member.
[0019] Spring receptacle 26 comprises a second increased diameter portion in bore 12 spaced farther from end 13 than valve receptacle 16 . Spring receptacle 26 is bounded by a lower annular shoulder 27 and an upper annular shoulder 28 . The inner diameter of spring receptacle 26 is greater than the outer diameter of flow tube 50 , creating an annular chamber 29 therebetween. A coil spring 30 is preferably disposed in chamber 29 between lower annular shoulder 27 of spring receptacle 26 and annular extension 56 of flow tube 50 . Spring 30 is preferably sized such that it is compressed and urges flow tube 50 away from first end 13 even when annular extension 56 bears on upper annular shoulder 28 .
[0020] Eccentric gearbox receptacle 36 comprises a third enlarged portion in bore 12 and is spaced farther from end 13 than spring receptacle 26 . Eccentric gearbox receptacle 36 comprises a lower portion 37 and an upper portion 38 . Lower portion 37 houses at least one and preferably a plurality of drive motors 40 , gearboxes 42 , and gears 44 . Upper portion 38 houses a rotating sleeve 46 . Rotating sleeve 46 includes a looped groove 48 , which includes a helical portion 47 , a short, transverse portion 51 , and a straight portion 49 . Looped groove 48 receives follower pin 59 on flow tube 50 . When closure element 20 is in the closed position shown in FIG. 1, follower pin 59 is disposed at a junction between straight portion 49 and helical portion 47 .
[0021] Drive motors 40 , gearboxes 42 , gears 44 and rotating sleeve 46 are preferably operably connected such that power supplied to drive motors 40 causes motors 40 drive gearboxes 42 , which in turn drive gears 44 , which in turn cause rotating sleeve 46 to rotate about the axis of body 10 and flow tube 50 . FIG. 3 is a cross-sectional view along the axis of the device with the rotating sleeve 46 removed so as to show the plurality of gearboxes 42 and gears 44 . FIG. 3 also illustrates the extension of follower pin 59 from the outer surface of flow tube 50 .
[0022] Guide groove 46 extends longitudinally along a portion of bore 12 and receives non-annular extension 58 of flow tube 50 . Referring briefly to FIGS. 4 and 5, guide groove 46 preferably is wide enough to include at least a pair of retaining members 68 . Retaining members 68 are actuable between an open position, shown in FIG. 4, and a closed position, shown in FIG. 5. In their closed position, retaining members 68 engage extension 58 so as to prevent flow tube 50 from moving relative to body 10 .
[0023] Retaining members 68 and drive motors 40 receive electrical power from electrical leads 7 , 9 , respectively. Conductors 7 , 9 preferably enter body 10 through electrical penetrator 8 . Conductors 7 , 9 electrically connect to a local control unit 100 , which is in turn electrically connected to a remote control unit 102 .
[0024] A plurality of seals 70 are preferably provided between body 10 and flow tube 50 so as to isolate guide groove 46 , eccentric gearbox receptacle 36 , and spring receptacle 26 and prevent the ingress of fluid thereinto.
[0025] Operation
[0026] When it is desired to open bore 12 and allow fluid flow therethrough, a preferred first step is to equalize pressure on both sides of closure element 20 . With pressure equalized, power is supplied to motors 40 via conductors 9 . Motors 40 drive gearboxes 42 , which in turn advance gears 44 , causing sleeve 46 to rotate such that follower pin 59 enters the helical portion 47 of loop 48 . As sleeve 46 rotates, helical groove 47 bears on pin 59 , urging flow tube 50 toward first end 13 of body 10 . Because flow tube 50 is prevented from rotating by engagement of extension 58 with guide groove 46 , the rotation of sleeve 46 causes flow tube 50 to advance longitudinally through body 10 . As flow tube 50 advances relative to body 10 in response to the force applied by rotating sleeve 46 , annular extension 56 compresses spring 30 and first end 53 bears on closure element 20 , forcing it open. If pressure is not equalized before the opening sequence, more power may be required to open the valve.
[0027] When the opening process is complete, the tool is in the position shown in FIG. 2. Specifically, end 53 of flow tube 50 rests on frustoconical shoulder 17 and closure element 20 is contained between body 10 and flow tube 50 . Bore 12 is open along the length of the tool, spring 30 is compressed, and follower pin 59 rests at the juncture of helical portion 47 and straight portion 49 , as shown in phantom. At this point, power is supplied to retaining members 68 , causing them to come together and engage extension 58 of flow tube 50 so as to prevent it from moving axially within body 10 . Rotation of sleeve 46 is then preferably continued, without further advancing flow tube 50 , as follower pin 59 traverses transverse portion 51 of loop 48 , until follower pin 59 rests at the juncture of transverse portion 51 and straight portion 49 , as shown in FIG. 2.
[0028] Because the present invention is normally closed, it is a fail-safe valve. Once the device has attained the open state shown in FIG. 2, flow can continue through it until either the device is closed deliberately, the power supplied to retaining members 68 is interrupted, or retaining members 68 fail. When any of these events occurs, retaining members 68 cease to hold extension 58 and thus cease to prevent flow tube 50 from moving axially. This allows spring 30 to drive flow tube 50 away from first end 13 . As flow tube 50 advances toward second end 14 , follower pin 59 traverses straight portion 49 of loop 48 . Flow tube 50 is sized such that when annular extension 56 bears on upper annular shoulder 28 , its first end 53 clears upper annular shoulder 18 , allowing closure element 20 to fully close bore 12 .
[0029] Because the device preferably includes a plurality of motors 40 , a plurality of gearboxes 42 , and a plurality of gears 44 , it is multiply redundant, ensuring that it remains operable even in the event that one or more of its components fail. In addition, the gear train may be fitted with multiple slip clutches that will allow the device to operate even if one or more of the redundant drive motors fail.
[0030] Retaining members 68 can be any electrically actuable device and are shown as a pair of electrically actuated dogs. In a preferred embodiment, retaining members 68 each comprise at least one flux carrier in conjunction with at least one coil. The coils are connected to conductors 7 . When power is supplied to the coils, they induce flux in the flux carriers, which in turn advance toward extension 58 and ultimately engage it. By using electrical actuation and electrical power, the present device avoids the need for hydraulic systems.
[0031] Flow tube 50 preferably includes a static sealing member at its first end 53 , which forms a seal with frustoconical shoulder 17 when the device is open. Flow tube 50 can be rotated to remove deposits that would otherwise impede travel of the tube. In some embodiments, flow tube 50 includes a toothed cutting edge to facilitate removal of deposits.
[0032] In still another alternative embodiment, the relative positions of the drive mechanism and spring 30 may be reversed, such that the flow tube is pulled into the open position against the spring force. In this embodiment it is still preferred that the device be normally closed, so that it can function as a fail-safe device. Nonetheless, it is contemplated that in other embodiments, the configuration may be modified such that the device is normally open. In these embodiments, the relative positions of spring 30 and the drive mechanism may again be such that the drive mechanism either pulls or pushes the flow tube into the closed position.
[0033] While certain preferred embodiments of the present invention has been shown and described, it will be understood that a variety of modifications could be made thereto without departing from the scope of the present invention. For example, the guiding and retaining functions performed by extension 58 could be performed by separate elements. Closure element 20 , shown above as a single component could comprise multiple components and/or could operate in various other ways. For example, closure element 20 could comprise a shutter-type closure, a ball valve, a stopcock-type closure, or any other suitable closure device. Likewise, the spring- loaded pivoting mechanism described above could comprise any suitable biasing means such as are known in the art.
[0034] The drive mechanism described above as formed by the combination of gears, rotating sleeve, and follower pin could be replaced with a drive mechanism comprising solely gears, with the drive motors rotating a set of gears to either directly or indirectly advance the flow tube. For example, the flow tube could include gear teeth on a portion of its outer surface. Similarly, a plurality of powered drive mechanisms can be included and can include one-way drive clutches. The drive mechanism(s) can be configured so as to allow nonfunctioning drive mechanisms to be mechanically decoupled.
[0035] Coil spring 30 can be replaced with a biasing means that is better suited to operate in tension, rather than in compression, if desired. Flow tube 50 can be replaced with a non-tubular element, although a tubular element is preferred because it is mechanically robust and protects the various components of the device from contact with the fluid. Similarly, retaining members 68 could be replaced with a single member, or multiple members, mounted inline with extension 58 , which when face to face with extension 58 can retain extension 58 when energized.
[0036] The embodiments described herein are exemplary only and are not limiting. One skilled in the art will understand that the mechanisms described herein could each be replaced with alternative mechanisms, so long as the invention is within the scope of the claims that follow. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims which follow, the scope of which shall include all equivalents of the subject matter of the claims. Also, in the claims that follow, the sequential recitation of steps is not intended to require that the steps be performed in the order recited, or that any given step be completed before another step is begun. | An electrically actuated fail-safe valve for controlling fluid flow in deepwater drilling operations comprises a body having a bore therethrough, a closure element mounted in the bore and actuable between a closed position and an open position, a flow tube slidably mounted in the bore, the tube being actuable between a first position in which it does not interfere with the normal bias of the closure and a second position in which it opposes the normal bias of the closure, and a drive mechanism causing the tube to advance from its first to its second position. The drive mechanism comprises a gear drive, a rotating sleeve including a helical groove, and a follower pin on the flow tube and received in the helical groove. Power supplied to the drive causes the sleeve to rotate, bearing on the follower pin and advancing the flow tube to its second position. | 4 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to copending Provisional Application No. 60/666,627 filed on Mar. 31, 2005, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photomultiplier that enables a cascade-multiplication of secondary electrons by emitting sequentially the secondary electrons through a plurality of stages in response to incidence of photoelectrons.
2. Related Background Art
In recent years, developments of TOF-PET (Time-of-Flight-PET) are earnestly proceeding as a PET (Positron-Emission Tomography) apparatus for the next generation in the field of nuclear medicine. In particular, in the TOF-PET apparatus, when two gamma rays emitted from a radioactive isotope administered in a body are simultaneously measured at two detectors in directions opposite to each other, a time difference in signals outputted from the two detectors can be determined, which enables to determine a disappeared position of positrons as a difference in flight or transit time; thus, it becomes possible to obtain a vivid image of the PET. A photomultiplier with a large capacity having an excellent high-speed response is employed for the detectors.
For example, a photomultiplier shown in JP-A-5-114384 is known as the aforementioned one. In the conventional photomultiplier has a construction such that a focusing electrode and an accelerating electrode are arranged in this turn from a cathode toward a first-stage dynode. In this case, the focusing electrode is the one correcting an orbit of each photoelectron emitted from the cathode such that the photoelectrons may be focused on the first-stage dynode. In addition, the accelerating electrode is the one accelerating the photoelectrons emitted from the cathode to the first-stage dynode, and has a function to reduce variations in transit time from the cathode to the first-stage dynode caused by the emission area of the photoelectrons of the cathode.
A photomultiplier with an excellent high-speed response can be obtained by the configuration arranging the focusing electrode and accelerating electrode between the cathode and the first-stage dynode, as mentioned above.
SUMMARY OF THE INVENTION
The inventors have studied the foregoing prior art in detail, and as a result, have found problems as follows.
Namely, in the conventional photomultiplier, an electron-multiplying unit housed in a sealed container and performing an excellent high-speed response is constructed by a dynode unit such that a plurality of stages of dynodes together with an anode are sandwiched between a pair of insulating fixing plates, a focusing electrode, and an accelerating electrode. In the assembly work, the accelerating electrode is fixed to the dynode unit by a specific metal member, while the focusing electrode is fixed to the accelerating electrode through a glass member. In the photomultiplier including the thus assembled electron-multiplying unit, a high positional accuracy is required for fixings of the focusing electrode and accelerating electrode to perform a high-speed response of the photomultiplier.
However, the fixing of the focusing electrode to the accelerating electrode is carried out such that the two ends of the glass material are fixed by welding at the fixing area extending from the focusing electrode and the fixing area extending from the accelerating electrode, respectively. For this reason, the fixing work of the focusing electrode is a work involving a high level of difficulty such that some experience for the worker himself is required. In addition, because the number of steps for assembling the whole electron-multiplying unit may be increased, upon mass-production of the multiplier, it is difficult to shorten the producing time and reduce variations in performance thereof.
The present invention is made to solve the aforementioned problem, and in order to perform a high gain and achieve a higher productivity in a state keeping or improving a high-speed response, it is an object to provide a photomultiplier having a structure which enables an integrated assembly of an electron-multiplying unit including a focusing electrode and an accelerating electrode, that is, a structure preferred to the mass-production.
A photomultiplier according to the present invention comprises a sealed container of which the inside is kept in a vacuum state, and a cathode, a focusing electrode, an accelerating electrode, a dynode unit, and an anode each to be accommodated in the sealed container. In addition, the dynode unit and anode are unitedly held in a state sandwiched by a pair of insulating support members. The cathode emits photoelectrons as first electrons within the sealed container in response to incidence of light having a predetermined wavelength. The dynode unit includes a plurality of stages of dynodes for emitting secondary electrons in response to the photoelectrons reached from the photocathode to cascade-multiply sequentially the photoelectrons. The anode takes out the secondary electrons cascade-multiplied by the dynode unit as a signal. The focusing electrode functions to correct the orbit of each photoelectron emitted from the photocathode, and is arranged between the photocathode and dynode unit. Further, the focusing electrode has a through hole through which the photoelectrons from the photocathode pass. The accelerating electrode functions to accelerate the photoelectrons reached from the photocathode via the focusing electrode, and is arranged between the focusing electrode and dynode unit. Also, the accelerating electrode has a through hole through which the photoelectrons reached from the photocathode via the focusing electrode pass.
In particular, in the photomultiplier according to the present invention, the accelerating electrode composes a lower electrode and an upper electrode fixed each other by welding at a plurality of spots. The lower electrode is held by the pair of insulating support members in a state for the pair of insulating support members to grasp unitedly it together with the dynode unit and anode. On the other hand, the upper electrode has one or more slit grooves pinching a part of the pair of insulating support members, and is attached with the lower electrode in a state for the slit grooves to pinch the pair of insulating support members.
As a specific fixture structure of the accelerating electrode, for example, it is preferable that the pair of insulating support members each have at least one or more protruding portions serving as a reference of the arranged positions of the focusing electrode and accelerating electrode, extending toward the photocathode. Additionally, it is preferable that the protruding portions each have a fixture structure for fixing the accelerating electrode in a state of supporting directly the accelerating electrode. In this case, the protruding portions are respectively arranged at predetermined positions of the pair of insulating support members to surround at least the accelerating electrode in a state of grasping the dynodes and anode.
In the aforementioned photomultiplier, when the protruding portions (attached with the fixture structure) serving as a reference of the arranged position of at least the accelerating electrode is provided for each of the pair of insulating support members for grasping the dynode unit and anode, the accelerating electrode together with the dynode unit and anode may be fixed unitedly to the pair of insulating support members. In other words, due to the structure fixing the accelerating electrode, provided at a part of the pair of insulating support members for grasping unitedly the dynode unit and anode, the accelerating electrode constituting a part of the electron-multiplying unit can be easily aligned by using the pair of insulating support members as a reference member. As a result, on assembly of the electron-multiplying unit, alignment work with high precision between the members, specific fixing members and fixing jigs becomes unnecessary, which enables to improve drastically the productivity of the electron-multiplying unit accommodated in the sealed container. In addition, variations in performance between produced photomultipliers can be reduced irrespective of skilled degree of workers themselves.
Here, it is preferable that a fixture structure provided at each of the protruding portions includes a slit groove for pinching a part of the lower electrode of the accelerating electrode. Additionally, the upper electrode of the accelerating electrode is welded to the lower electrode in a state for the grooves provided on the upper electrode to pinch the protruding portions provided at each of the pair of insulating support members. Thus, when the part of the accelerating electrode is pinched by the corresponding slit grooves, alignment work and fixing work of the accelerating electrode can be carried out simultaneously.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cutaway view illustrating a schematic structure of a photomultiplier of a first embodiment according to the present invention;
FIG. 2 is an assembly process view for explaining the construction of an electron-multiplying unit applied to the photomultiplier according to the present invention;
FIG. 3 is a view for explaining the structure of a pair of insulating support members constructing a part of the electron-multiplying unit;
FIG. 4 is a plan view and a side view for explaining the structure of a lower electrode in an accelerating electrode;
FIG. 5 is a plan view and a side view for explaining the structure of an upper electrode in the accelerating electrode;
FIG. 6 is a view for explaining a mounting process of the accelerating electrode to the pair of insulating support members;
FIG. 7 is an enlarged view for explaining the mounting process of FIG. 6 in further detail;
FIG. 8 is a plan view and a side view for explaining the structure of the focusing electrode;
FIG. 9 is a view for explaining a mounting process of the focusing electrode to the pair of insulating support members;
FIG. 10 is an enlarged view for explaining the mounting process of FIG. 9 in further detail; and
FIG. 11 is a side view illustrating an electron-multiplying unit applied to the photomultiplier according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, embodiments of a photomultiplier according to the present invention will be explained in detail with reference to FIGS. 1 to 11 . In the explanation of the drawings, constituents identical to each other will be referred to with numerals identical to each other without repeating their overlapping descriptions.
FIG. 1 is a partially cutaway view illustrating a schematic structure of a photomultiplier of an embodiment according to the present invention.
As shown in FIG. 1 , a photomultiplier 100 includes a sealed container 110 provided with a pipe 130 (solidified after evacuation) for evacuating the inside at the bottom thereof, a cathode 120 provided in the sealed container 110 and an electron-multiplying unit.
The sealed container 110 is constituted by a cylindrical body having a face plate, the inside of which is formed with a cathode 120 , and a stem supporting a plurality of lead pins 140 in their penetrating state. The electron-multiplying unit is held at a predetermined position within the sealed container 110 by the lead pins 140 extending from the stem to the inside of the sealed container 110 .
The electron-multiplying unit is constituted by a focusing electrode 200 , an accelerating electrode 300 , and a dynode unit 400 disposing an anode thereinside. The focusing electrode 200 is an electrode correcting an orbit of each photoelectron emitted from the cathode 120 such that the photoelectrons may be focused to the dynode unit 400 , and has a through hole which is arranged between the cathode 120 and dynode unit 400 and through which the photoelectrons from the cathode 120 pass. In addition, the accelerating electrode 300 is an electrode accelerating the photoelectrons emitted from the cathode 120 to the dynode unit 400 , and has a through hole that is arranged between the focusing electrode 200 and dynode unit 400 such that the photoelectrons passed through the through hole of the focusing electrode can be further accelerated toward the dynode unit 400 . Due to the accelerating electrode 300 , a variation in transit time of the photoelectrons reached from the cathode 120 to the dynode unit 400 can be reduced, though it is caused by the photoelectrons emitting area of the cathode 120 . Furthermore, the dynode unit 400 includes a plurality of stages of dynodes cascade-multiplying sequentially secondary electrons emitted in response to the photoelectrons reached from the cathode 120 through the focusing electrode 200 and accelerating electrode 300 , an anode taking out the secondary electrons cascade-multiplied by means of these plurality of stages of dynodes, and a pair of insulating support members grasping unitedly these plurality of stages of dynodes and the anode.
FIG. 2 is an assembly process view for explaining the construction of the electron-multiplying unit applied to the photomultiplier according to the present invention.
As shown in FIG. 2 , the electron-multiplying unit is constituted by the focusing electrode 200 , accelerating electrode 300 , and dynode unit 400 including the anode. The focusing electrode 200 is provided with a through hole through which the photoelectrons from the cathode 120 pass. The accelerating electrode 300 is constituted by an upper electrode 310 and a lower electrode 320 to improve an assembling efficiency of the electron-multiplying unit. These upper electrode 310 and lower electrode 320 are integrated by welding at several spots during the assembly work of the electron-multiplying unit. The dynode unit 400 is constituted by first to seventh dynodes DY 1 -DY 7 each grasped by the first and second insulating support members 410 a , 410 b , an anode 420 , and a reflection-type dynode DY 8 reversing the electrons passed through the anode 420 toward the anode 420 again. In addition, in each of the first to seventh dynodes DY 1 -DY 7 and the reflection-type dynode DY 8 , a reflection-type emission surface of secondary electrons is formed by receiving photoelectrons or secondary electrons to emit newly secondary electrons toward the incident direction of the electrons. In addition, fixed pieces DY 1 a , DY 1 b are provided to be grasped by the first and second insulating support members 410 a , 410 b at the two ends of the first dynode DY 1 . Similarly, the second dynode DY 2 has fixed pieces DY 2 a , DY 2 b at its two ends; the third dynode DY 3 has fixed pieces DY 3 a , DY 3 b at its two ends; the fourth dynode DY 4 has fixed pieces DY 4 a , DY 4 b at its two ends; the fifth dynode DY 5 has fixed pieces DY 5 a , DY 5 b at its two ends; the sixth dynode DY 6 has fixed pieces DY 6 a , DY 6 b at its two ends; the seventh dynode DY 7 has fixed pieces DY 7 a , DY 7 b at its two ends; the anode 420 has fixed pieces 420 a - 420 d at its two ends; and the eighth dynode DY 8 has fixed pieces DY 8 a , DY 8 b at its two ends.
The lower electrode 320 of the accelerating electrode 300 is grasped by the first and second insulating support members 410 a , 410 b together with the first to seventh dynodes DY 1 -DY 7 , anode 420 , and reflection-type dynode DY 8 . Thus, the upper electrode 310 is fixed by welding at the lower electrode 320 in a grasped state by the first and second insulating support members 410 a , 410 b . On the other hand, the focusing electrode 200 is mounted at the protruding portions provided at the upper portions (cathode 120 side) of the first and second insulating support members 410 a , 410 b , and fixed at the first and second insulating support members 410 a , 410 b by welding of reinforcing members 250 a , 250 b.
In addition, as described above, in a state that the first to seventh dynodes DY 1 -DY 7 , anode 420 , and reflection-type dynode DY 8 are unitedly grasped, the first and second insulating support member 410 a , 410 b are further grasped by metal clips 450 a - 450 c ; thus, the aforementioned members are stably held by the first and second insulating support members 410 a , 410 b.
FIG. 3 is a view for explaining the structure of the first and second insulating support members 410 a , 410 b constituting a part of the electron-multiplying unit. In this case, since the first and second insulating support members 410 a , 410 b have the same structure, only the second insulating support member 410 b will now be explained for their common structure description below.
The insulating support member 410 b is provided with alignment holes D 1 -D 8 and 42 to be inserted by fixed pieces DY 1 b -DY 8 b , 420 b of the first to seventh dynodes DY 1 -DY 7 , anode 420 , and reflection-type dynode DY 8 . Also, the insulating support member 410 b is provided with notched portions 411 a - 411 c hooking the metal clips 450 a - 450 c in order to easily secure to the insulating support member 410 a grasping the members DY 1 -DY 8 , 420 together.
In particular, protruding portions 430 a , 430 b extending upwardly are provided at the insulating support member 410 b . Namely, the protruding portions 430 a , 430 b extend toward the cathode side when the electron-multiplying unit is mounted in the sealed container 110 . Then, at the protruding portion 430 a , a slit groove 431 a for aligning and fixing the accelerating electrode 300 as a first fixture structure, and a slit groove 432 a for aligning and fixing the focusing electrode 200 as a fixture structure are provided. Similarly, at the protruding portion 430 b , a slit groove 431 b for aligning and fixing the accelerating electrode 300 as a first fixture structure, and a slit groove 432 b for aligning and fixing the focusing electrode 200 as a fixture structure are provided.
Next, the structure of the accelerating electrode 300 will be explained with reference to FIG. 4 and FIG. 5 . FIG. 4 is a plan view and a side view for explaining the structure of the lower electrode 320 constituting a part of the accelerating electrode 300 . Also, FIG. 5 is a plan view and a side view for explaining the structure of the upper electrode 310 constituting a part of the accelerating electrode 300 .
The accelerating electrode 300 can be obtained by welding at several spots of the lower electrode 320 and upper electrode 310 having the structures as shown in FIGS. 4 and 5 . The lower electrode 320 is directly inserted and fixed in the slit grooves 431 a , 431 b , which are provided at the respective protruding portions 430 a , 430 b of the first and second insulating support members 410 a , 410 b.
Specifically, as shown in FIG. 4 , the lower electrode 320 is provided with notched portions 320 a - 320 d to be grasped to the first and second insulating support members 410 a , 410 b together with the first to seventh dynodes DY 1 -DY 7 , anode 420 , and reflection-type dynode DY 8 . In addition, at the flange portion located at the outer periphery of a through hole 321 provided at the accelerating electrode 320 , the notched portions 320 a - 320 d are arranged to surround the through hole 321 . On the other hand, as shown in FIG. 5 , the upper electrode 310 is constituted by a body unit 312 defining a through hole 311 and a flange portion at one open end of the body unit 311 . At the outer periphery of the flange portion, slit grooves 310 a - 310 d to sandwich the protruding portions 430 a , 430 b provided on each of the first and second insulating support members 410 a , 410 b are formed, and fixing section 313 a , 313 b to be fixed by welding to the lower electrode 320 are provided.
The lower electrode 320 and upper electrode 320 having the aforementioned structure, as shown in FIG. 6 , are fixed in a welded state to the first and second insulating support members 410 a , 410 b arranged to oppose each other.
First, the lower electrode 320 is grasped by the first and second insulating support members 410 a , 410 b with the first to seventh dynodes DY 1 -DY 7 , anode 420 , and reflection-type dynode DY 8 . At this time, the lower electrode 320 is grasped by the first and second insulating support members 410 a , 410 b in a state that areas (parts corresponding to regions 321 a - 321 d shown in FIG. 4 ) provided with the notched portions 320 a - 320 d of the flange portion are fit in the slit grooves 431 a , 431 b formed at the protruding portions 430 a , 430 b , respectively. As a result, the lower electrode 320 is fixed to the first and second insulating support members 410 a , 410 b in a state that the flange portion thereof is surrounded by the protruding portions 430 a , 430 b . Furthermore, FIG. 7 is an enlarged view illustrating a setting situation of the notched portion 320 a of the lower electrode 320 in particular. Note that the lower electrode 320 is aligned to only the direction designated by the arrow S 1 in FIG. 7 when it is grasped by the first and second insulating support members 410 a , 410 b ; however, it is still slightly rotatable to the direction designated by the arrow S 2 .
Subsequently, the upper electrode 310 , as shown in FIG. 6 , is disposed on the lower electrode 320 in a state that the protruding portions 430 a , 430 b are pinched into the slit grooves 310 a - 310 d . At this time, the upper electrode 310 , which is different from the lower electrode 320 , is movable to the direction represented by the arrow S 1 in FIG. 7 , but cannot be rotated to the direction represented by the arrow S 2 . For this reason, when the fixing areas 313 a , 313 b provided at the outer periphery of the flange portion of the upper electrode 310 are welded at the lower electrode 320 , the upper electrode 310 and lower electrode 320 are unitedly fixed (aligned) to the first and second insulating support members 410 a , 410 b.
Furthermore, FIG. 8 is a plan view and a side view for explaining the structure of the focusing electrode 200 .
In particular, the focusing electrode 200 is constituted by the body unit 210 shown in FIG. 8 (substantially a main body of the focusing electrode; there are some cases that the body unit 210 herein may be simply called ‘focusing electrode’) and the reinforcing members 250 a , 250 b controlling the rotation of the body unit 210 . The body unit 210 , as shown in FIG. 8 , has a flange portion that has a cylindrical shape, extends from one opening end of the body unit to the inside, and defines the through hole 211 . At the flange portion, notched portions 220 a - 220 d are formed to be grasped by slit grooves 432 a , 432 b provided at the protruding portions 430 a , 430 b of the first and second insulating support members 410 a , 410 b . Note that these notched portions 220 a - 220 d is constituted by introducing portions 221 a - 221 d for housing the protruding portions 430 a , 430 b via the through hole 211 in the focusing electrode 200 , and fixing portions 222 a - 222 d for limiting the rotation of the body unit 210 around the tube axis of the sealed container 110 .
The body unit 210 having the aforementioned structure is fixed to the slit grooves 432 a , 432 b formed at the respective protruding portions 430 a , 430 b of the first and second insulating support members 410 a , 410 b in such a manner that the body unit 210 itself rotates around the tube axis of the sealed container 110 .
Specifically, as shown in FIG. 9 , the protruding portions 430 a , 430 b of the first and second insulating support members 410 a , 410 b that grasp the first to seventh dynodes DY 1 -DY 7 , anode 420 , reflection-type dynode DY 8 , and accelerating electrode 300 are inserted into the through hole 211 of the body unit 210 . The situation of this case is shown in an enlarged view of FIG. 10 .
In other words, the protruding portions 430 a , 430 b are inserted from the introducing portions 221 a - 221 d in the notched portions 220 a - 220 d along the direction designated by the arrow S 4 in FIG. 10 . Thereafter, the body unit 210 rotates in the direction designated by the arrow S 3 shown in FIG. 10 , so that the slit grooves 432 a , 432 b of the protruding portions 430 a , 430 b can abut with the fixing sections 222 a - 222 d . At this time, the slit grooves 432 a , 432 b of the protruding portions 430 a , 430 b may grasp the areas designated by 223 a - 223 d of the flange portion of the body unit 210 . In this way, the body unit 210 itself is fixed to the direction designated by the arrow S 4 in FIG. 10 . However, since the body unit 210 is not fixed to the direction designated by the arrow S 3 , the reinforcing members 250 a , 250 b are fixed by welding to restrict the rotation along the direction designated by the arrow S 3 of the body unit 210 .
The reinforcing member 250 a is constituted by a main body plate 251 a abutted with the flange portion of the body unit 210 and a spring portion 252 a abutted with the side of the body unit 210 . Also, the main body plate 251 a is provided with a slit groove 253 a for pinching the protruding portions 430 a of the first and second insulating members 410 a , 410 b arranged to oppose each other. In similar, the reinforcing member 250 b is constituted by a main body plate 251 b abutted with the flange portion of the body unit 210 and a spring portion 252 b abutted with the side of the body unit 210 . Also, the main body plate 251 b is provided with a slit groove 253 b for pinching the protruding portion 430 b of the first and second insulating members 410 a , 410 b arranged to oppose each other.
These reinforcing members 250 a , 250 b are inserted from the direction designated by the arrow S 5 in FIG. 11 (the slit grooves 253 a , 253 b pinching the protruding portions 430 a , 430 b ). As described above, the body unit 210 is fixed in the direction designated by the arrow S 4 in FIG. 10 ; however, it is not fixed in the direction designated by the arrow S 3 . On the other hand, the reinforcing members 250 a , 250 b pinch the protruding portions 430 a , 430 b by the slit grooves 253 a , 253 b to thereby be fixed in the direction designated by the arrow S 3 , while they are fixed in the direction designated by the arrow S 4 . When the above body unit 210 and each of the reinforcing members 250 a , 250 b are fixed by welding, the focusing electrode 200 is unitedly fixed (aligned) to the first and second insulating members 410 a , 410 b.
The electron-multiplying unit to be housed in the sealed container 110 through the above assembly processes.
From the invention thus described, it will be obvious that the embodiments of the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims. | The present invention relates to a photomultiplier having a structure for performing a high gain and achieving a higher productivity in a state keeping or improving an excellent high-speed response. In the photomultiplier, an electron-multiplying unit accommodated in a sealed container has a structure that enables an integrated assembly of a focusing electrode, an accelerating electrode, a dynode unit, and an anode. Specifically, the accelerating electrode composes a lower electrode and an upper electrode fixed each other by welding at a plurality of spots. The lower electrode is held at a pair of insulating support members in a state for the pair of insulating support members to grasp unitedly it together with the dynode unit and anode. Additionally, the upper electrode has one or more slit grooves for pinching a part of the pair of insulating support members. With this construction, the accelerating electrode constituted by the lower electrode and upper electrode is fixed at the pair of insulating support members in a state to be aligned with high accuracy by using the pair of insulating support members as a reference member. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in, general to a wire grid polarizer and a manufacturing method thereof, more particularly, to a wire grid polarizer for visible light and a manufacturing method thereof.
[0003] 2. Discussion of the Background Art
[0004] The use of an array of parallel conducting wires to polarize specific light of radio waves dates back more than 100 years.
[0005] The array of parallel conducting wires is generally called a wire grid. The wire grid, formed on a transparent substrate, is also used as a polarizer for the infrared portion of the electromagnetic spectrum.
[0006] The key factor that determines the performance of a wire grid polarizer is the relationship between the wire-to-wire spacing, namely period of the parallel grid elements and the wavelength of the incident light.
[0007] If the period of the wire grid is longer than the wavelength of the incident light, the wire grid functions as a diffraction grating, rather than as a polarizer, and diffracts the polarized incident light;
[0008] Then, according to well-known principles, a diffraction and interference pattern is formed.
[0009] However, if the period or the grid spacing is shorter than the wavelength, the wire grid functions as a polarizer that reflects electromagnetic radiation polarized parallel to the grid, and transmits radiation of the orthogonal polarization.
[0010] Quality criteria for the manufacture of a wire grid polarizer beam splitter are period, line width, characteristics of grid material, substrate features (index of refraction), and wavelength and incidence angle of the incident light.
[0011] Here, many studies show that the characteristics of grid material have the least effect on the performance features of the polarization beam splitter.
[0012] FIG. 1 illustrates a related art wire grid.
[0013] As shown in FIG. 1 , the wire grid 100 is composed of a plurality of parallel conductive wires 110 supported by an insulating substrate 120 .
[0014] The period of the conductive wire 110 is denoted as ‘Λ’, the width of the conductive wire 110 is denoted as ‘w’, and the thickness of the conductive wire is denoted as ‘t’.
[0015] Based on the general definitions of the S-polarization and the P-polarization, the S polarized light has a polarization vector orthogonal to the plane of incidence and thus, it is parallel to the conductive elements.
[0016] In contrast, the P polarized light has a polarization vector parallel to the incidence plane and thus, it is orthogonal to the conductive elements.
[0017] If the period (or the center-to-center spacing) of the conductive wires 110 is shorter than the wavelength of the electromagnetic radiation, the wire grid reflects the polarization element (s-polarization) parallel to the conductive wires 110 , and transmits the polarization element (p-polarization) orthogonal to the conductive wires 110 .
[0018] Usually, the wire grid polarizer reflects light with its electric field vector parallel to the conductive wires, and transmits light with its electric field vector perpendicular to the conductive wires. Meanwhile, the plane of incidence may or may not be perpendicular to the wires of the grid. The geometric notations used here are for information clarification.
[0019] An ideal wire grid will function as a perfect mirror for one polarization of light, the S polarized light, and will be perfectly transparent for the other polarization, the P polarized light for example.
[0020] In practice, however, reflective metals used as mirrors absorb some fraction of the incident light and reflect only 90-95%, and plain glass does not transmit 100% of the incident light because of surface reflections.
[0021] Referring back to FIG. 1 , the performance of the wire grid polarizer can be characterized by the polarization extinction ratio and the transmittance.
[0022] Here, the polarization extinction ratio and the transmittance are expressed by the following equations.
Polarization extinction ratio: (Si/St)| Pi=0
Transmittance: (Pt/Pz)| Si=0
[0023] In the equations, the polarization extinction ratio indicates the ratio of the optical power of the incidented S wave (Si) to the transmitted S wave St) when the S polarized light incidents; and the transmittance indicates the ratio of the optical power of the incidented P wave (Pt) to the incidented P wave (Pi) when the P polarized light incidents.
[0024] For the wire grid polarizer to have a high polarization extinction ratio, the period of the wire grid should be much shorter than the wavelength of the incident light.
[0025] So far, it has been very difficult to manufacture wire grid polarizers with a shorter period of the wire grid, so wire grid polarizers were developed only for use in the infrared or microwave regions. Primarily, this is because the period of the wire grid needs to be shortened as the wavelength of the polarized light has the short wavelength.
[0026] However, with recent advances in semiconductor fabrication equipment and exposure technologies, including the fine pattern generation technology, it is now possible to produce wire grid polarizers for visible light.
[0027] The visible light resides in the electromagnetic spectrum which is visible to human eyes. The visible spectrum consists of wavelengths between 400 nm to 700 nm
[0028] That is, for the wire grid polarizer to have the high ERs (Extinction Ranges) for three primary colors (R, G, and B), the period of the wire grid should be at least 200 nm to obtain somewhat desired polarization characteristics. To improve the polarization performance of existing polarizers, a wire grid with its period shorter than 0.1 μm is required.
[0029] The line width of a recently developed semiconductor processing is approximately 0.1 μm When drawing lines periodically, the spacing between the lines should be the same with the line width, which means that the period of the wire grid is 0.2 μm.
[0030] Here, if the interference effect can be generated by using an argon laser having a short wavelength, it is possible to make the period of the wire grid as short as 200 nm.
[0031] Also, if the period of the related art wire grid polarizer is reduced from 200 nm to 100 nm, the performance of the wire grid polarizer will be noticeably improved. Therefore, there is a need to develop a wire grid polarizer with a short period.
SUMMARY OF THE INVENTION
[0032] An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
[0033] Accordingly, one object of the present invention is to solve the foregoing problems by providing a wire grid polarizer for visible light and a manufacturing method thereof using embossing technique, whereby wire grid polarizers can be more easily and repeatedly manufactured.
[0034] Another object of the present invention is to provide a wire grid polarizer having excellent polarizing performance at the R, G, and B wavelengths in the visible spectrum
[0035] The foregoing and other objects and advantages are realized by providing a manufacturing method of a wire grid polarizer, the method including the steps of: preparing a mold; sequentially forming a metal foil and a polymer on a substrate; molding a polymer by using the mold; etching the metal foil by using the molded polymer, and forming a wire grid pattern; and removing the polymer.
[0036] According to another aspect of the invention, a manufacturing method of a wire grid polarizer includes the steps of: preparing a mold; coating a substrate with a polymer; forming a polymer pattern by using the mold; etching the polymer pattern and exposing part of the substrate; depositing a metal foil onto the polymer pattern and the exposed substrate; and removing the polymer pattern.
[0037] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:
[0039] FIG. 1 illustrates a related art wire grid;
[0040] FIG. 2 is a graph showing the relationship between the period of a wire grid and the polarization extinction ratio in the visible light band;
[0041] FIGS. 3A through 3E diagrammatically illustrate a process for producing a mold for manufacturing a wire grid according to the present invention;
[0042] FIGS. 4A to 4 H illustrate a sequence of a manufacturing process of a wire grid polarizer, according to a first embodiment of the present invention; and
[0043] FIGS. 5A to 5 G illustrate a sequence of a manufacturing process of a wire grid polarizer, according to a second embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0044] The following detailed description will present a wire grid polarizer according to a preferred embodiment of the invention in reference to the accompanying drawings.
[0045] FIG. 2 is a graph showing the relationship between the period of a wire grid and the polarization extinction ratio in the visible light band.
[0046] As shown in FIG. 2 , the polarization efficiency of the wire grid polarizer is in a close relationship with the period of the wire grid.
[0047] The material of the wire grid is aluminum (Al), and the height of the wire grid is 140 mL
[0048] And, the line width of the wires of the grid is 60 nm, the periods of the R, the G, and the B light are 450 nm, 550 nm, and 650 nm, respectively.
[0049] To obtain the polarization extinction ratio higher than 10,000:1, the grid period should be shorter than 120 nm.
[0050] Before manufacturing the wire grid polarizer using the embossing technique, a mold should be prepared first.
[0051] FIGS. 3A through 3E diagrammatically illustrate a process for producing a mold for manufacturing the wire grid according to the present invention.
[0052] Preferably, the mold is made from silicon, SiO 2 , quartz glass, Ni, Pt, Cr, and polymers.
[0053] The embossing technique for use in the manufacture of the wire grid is largely divided into two types: hot embossing technique that applies heat for molding polymer, and UV embossing technique that presses the mold, and solidifies the polymer by using ultra violet light.
[0054] All of the above described materials can be used with the hot embossing technique. Particularly, quartz glass and transparent polymers which are transparent materials can also be used with the UV embossing technique.
[0055] Referring to FIG. 3A , a polymer layer 210 is sprayed or spin coated on a mold substrate 200 , such as silicon.
[0056] Preferably, the polymer layer 210 is made from an electron beam sensitive material, PMMA (polymethylmethacryiate) for example.
[0057] Multiplexing usually occurs in the electron beam sensitive part of the polymer, and using this nature, it is possible to obtain a desired pattern through electron beam irradiation and developing processes.
[0058] If the polymer is a positive photosensitizer, an electron beam irradiated part melts in the developer, while if the polymer is a negative photosensitizer, the rest of the polymer except for the electron beam irradiated part melt in the developer.
[0059] As shown in FIG. 3B , after the polymer layer 210 is formed on the mold substrate 200 a , a grid pattern is formed on the polymer layer 210 through the electron beam irradiation.
[0060] Next, as shown in FIG. 3C , the mold substrate 200 a and the polymer layer 210 are dipped in the developer to ensure the grid pattern is developed as it is.
[0061] As shown in FIG. 3D , the grid pattern is used as an etching mask and the mold substrate is dry etched or wet etched.
[0062] Lastly, the polymer layer used as the etching mask is removed, and as shown in FIG. 3E , the mold 200 b with a desired pattern for manufacturing the wire grid is produced.
[0063] Here, the surface of the mold is treated with a silane-containing chemical to facilitate the separation of the polymer and the mold.
[0064] Thusly prepared mold is then used for manufacturing the wire grid polarizer operating in the visible band.
[0065] FIGS. 4A to 4 H illustrate a sequence of a manufacturing process of a wire grid polarizer, according to a first embodiment of the present invention.
[0066] As described before, the wire grid polarizer is manufactured by using the pre-made mold. To this end, a transparent glass substrate 300 with both surfaces polished is first prepared (refer to FIG. 4A ).
[0067] Then, as shown in FIG. 4B , a thin metal foil 310 a is deposited on the glass substrate 300 .
[0068] The metal foil 310 a can be made from Al, Ag, or Cr.
[0069] Later, the metal foil 310 a is coated with a polymer 320 a , as shown in FIG. 4C
[0070] The polymer 320 a is pressed by the mold 330 , and as a result, the pattern from the mold is printed onto the polymer 320 a.
[0071] Here, if the polymer 320 a is a thermosetting material, a metal mold is employed, and if the polymer 320 a is a UV cure material, a transparent polymer mold is employed.
[0072] In the former case where the polymer 320 a is a thermosetting material, the hot embossing technique is used to pre-bake the polymer. In the later case where the polymer 320 a is a UV cure material, the UV embossing technique is used, so that the coated polymer is not cured and a transparent mold is used.
[0073] As shown in FIG. 4D , by applying heat or irradiating ultraviolet light onto the mold 330 , the polymer 320 b is cured or solidified.
[0074] Afterwards, as shown in FIG. 4E , the mold 330 is separated from the polymer 320 b.
[0075] Then, the pattern from the mold 330 is printed onto the polymer 320 b , that is, the polymer has an opposite pattern to the pattern from the mold 330 .
[0076] In case of using the hot embossing technique, the mold 330 has to be separated from the polymer 320 b after the temperature of the substrate is sufficiently cooled down.
[0077] In case of using the UV embossing technique, the mold 330 is separated from the polymer 320 b after the UR curing is finished.
[0078] Next, the front surface of the polymer 320 b is dry etched to exposure the surface of the metal foil 310 a , as shown in FIG. 4F .
[0079] Since part of the polymer 320 c is recessed by the pattern from the mold 330 , a relatively thin part of the polymer 320 c is removed by the etching process, thereby exposing the metal foil 310 a to the surface.
[0080] Afterwards, the exposed metal foil 310 a is dry etched or wet etched, and as a result, a wire grid pattern 310 b is formed as shown in FIG. 4G .
[0081] Finally, as shown in FIG. 4H the polymer 320 c remaining on the wire grid pattern 310 b is removed.
[0082] In this procedure, the wire grid polarizer with a desired grin pattern on the substrate 300 is manufactured.
[0083] FIGS. 5A to 5 G illustrate a sequence of a manufacturing process of a wire grid polarizer, according to a second embodiment of the present invention.
[0084] As explained before, the wire grid polarizer is manufactured by using the pre-made mold. To this end, a transparent glass substrate with both surfaces polished is first prepared (refer to FIG. 5A ).
[0085] Later, as shown in FIG. 5B , the glass substrate 400 is coated with a polymer 410 a , and the mold 430 is prepared.
[0086] Then, the polymer 410 a is pressed by the mold 430 , and as a result, the pattern from the mold 430 is printed onto the polymer 410 b , as shown in FIG. 5G
[0087] The pattern printed onto the polymer 410 b is opposite to the pattern from the mold 430 .
[0088] As shown in FIG. 5D , by applying heat or irradiating ultraviolet light onto the mold 430 , the polymer 410 b is cured or solidified
[0089] In case of using the hot embossing technique, the mold 430 has to be separated from the polymer 410 b after the temperature of the substrate 400 is sufficiently cooled down.
[0090] In case of using the UV embossing technique, the mold 430 is separated from the polymer 410 b after the UR curing is finished.
[0091] Here, if the polymer is a thermosetting material, a metal mold is employed, and if the polymer is a UV cure material, a transparent polymer mold is employed.
[0092] In the former case where the polymer is a thermosetting material, the hot embossing technique is used to pre-bake the polymer. In the later case where the polymer is a UV cure material, the UV embossing technique is used, so that the coated polymer is not cured and a transparent mold is used.
[0093] Afterwards, the front surface of the polymer 41 cb is dry etched to exposure the surface of the substrate 400 , as shown in FIG. 5E .
[0094] Since part of the polymer 410 c is recessed by the pattern from the mold 430 , a relatively thin part of the polymer 410 c is removed by the etching process, thereby exposing the substrate 400 to the surface.
[0095] Next, a metal foil 420 a is vacuum deposited on the glass substrate 400 , as shown in FIG. 5F .
[0096] The metal foil 420 a can be made from Al, Ag, or Cr.
[0097] Later, the polymer 410 c with the deposited metal foil 420 a is dipped into an etchant and is removed. At the end, a wire grid pattern 420 b shown in FIG. 5G is obtained.
[0098] In this procedure, the wire grid polarizer with a desired grin pattern on the substrate 400 is manufactured.
[0099] In conclusion, the wire grid polarizer of the present invention is advantageous for reducing the manufacture cost in that it can be mass produced by using a mold over and over.
[0100] Also, the manufacturing method of the wire grid polarizer of the present invention does not require additional equipment, and its process takes a short time, consequently increasing yield.
[0101] Moreover, the wire grid polarizer has the high polarization extinction ratio at visible wavelengths, so that it can be broadly used in diverse applications such as flat displays, projection displays, optical equipment, and so on.
[0102] While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skied in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
[0103] 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. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. | A manufacturing method of a wire grid polarizer includes the steps of: preparing a mold; sequentially forming a metal foil and a polymer on a substrate; molding a polymer by using the mold; etching the metal foil by using the molded polymer, and forming a wire grid pattern; and removing the polymer. | 6 |
PRIORITY DATE
[0001] This application claims the benefit of U.S. Provisional Application No. 60/349,489, which has been granted a filing date of Jan. 18, 2002.
TECHNICAL FIELD
[0002] The invention relates to devices and methods for packaging integrated circuit (IC) devices. More particularly, the invention relates to devices and methods using vias among adjoining layers of semiconductor packages for improved bonding and reduced mechanical stress.
BACKGROUND OF THE INVENTION
[0003] In use, integrated circuits (ICs) generally require electrical connections to a substrate to form a package providing electrical connections to additional electronic devices. In general a package substrate may include, but not be limited to, multiple layers of semiconductor, mask, conductive and non-conductive materials, dielectrics, encapsulates, thermal management items, etc., depending upon the complexity of the electrical connections to be made. In practice, the more layers, the higher the manufacturing effort and expense. Frequently an IC die is included on a package substrate along with other ICs or one or more discrete passive components such as resistors, capacitors, and so forth.
[0004] A die is typically attached to a “bond pad” using an adhesive such as epoxy, solder, or some form of eutectic metal that attaches the die without introducing damaging temperature, stress, or contamination into the semiconductor die. This “die attach material” can be purely mechanical or chemical bonding or a combination of chemical/mechanical bonds to form electrical and/or thermal paths, or neither, serving only as a substrate. With any combination thereof, the ability of the attach material to maintain a bond is critical in most applications. Failure of the die attach bond, or other bonded interface, can result in package failure resulting in overall electrical failure in the final system.
[0005] A common method to “bond” a semiconductor to a PC board is with a “leaded” package. The package leads are typically bonded with a combination of metals that reflow (melt) typically around 160 to 260 degrees Celsius, achieving a mechanical, chemical or chemical/mechanical bond between the lead and the PC board. Epoxy pastes are also used to form bonds. Such bonds may serve as the electrical contact between the device and the board and may also serve as a thermal path or as neither, merely affixing the components together.
[0006] Failure in the die attach, or various layers, usually shows as a “delamination,” or separation, at one or more of the interfaces. This failure may occur in the bulk of the die attach material, at the die attach to die, or die attach to bond pad interface or one of the many other layers. This separation is visually observed as a “crack” in the one or more of the layers. Likewise, failure at the lead to bond pad may show similar failure mechanisms.
[0007] Packaging methods and devices providing for strong and durable bonds resistant to mechanical failure/fatigue would be useful and desirable in the arts. Increases in bonding strength for packaged devices would also lead to flexibility in terms of improvements in package size and concurrent design limitations.
SUMMARY OF THE INVENTION
[0008] In general, devices and methods providing improved semiconductor package performance resistant to mechanical stresses are disclosed.
[0009] According to one aspect of the invention, a multi-layer laminated semiconductor package includes first and second layers, at least one of which is perforated by vias. The layers adjoin one another along approximately planar surfaces with the vias providing additional bonding structure. An attach material is provided between the attaching surfaces of the layers and within the vias, ensuring a secure bond.
[0010] According to another aspect of the invention, one of the layers is a semiconductor die.
[0011] According to another aspect of the invention, one of the layers is a semiconductor die lead foot.
[0012] According to other aspects of the invention, one of the layers is a bond pad, substrate or tape. Various bond surfaces may be used depending on package type.
[0013] According to still another aspect of the invention, the vias include an expanded end portion at a layer surface opposing the attach surface for accepting attach material.
[0014] According to an additional aspect of the invention, the vias are arranged at predetermined intervals.
[0015] According to yet another aspect of the invention, the vias are arranged at predetermined predicted stress points.
[0016] According to another aspect of the invention, a method is provided for bonding the layers of a multi-layer laminated semiconductor package. Steps in the method include perforating one or more layers with one or more vias. In a further step, attach material is introduced into the vias and between the layers such that the layers are securely bonded.
[0017] According to still another aspect of the invention, the perforating vias are formed by drilling.
[0018] According to yet another aspect of the invention, a step of predicting potential stress points is used for determining the arrangement of vias.
[0019] Technical advantages provided by the invention include, but are not limited to, stronger and improved failure-resistant bonds resulting in increased reliability, performance, and a potential reduction in the amount of attach material necessary for bonding. Further advantages are realized in the potential for making smaller packages due to flexibility for changes in lead and package geometry. For example, potential limiting factors in lead design, such as the minimum requirements for adequate solder coverage become less limiting with the use of the invention. Improvements in the reflow profiles in solder bonds may also be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] For a better understanding of the invention including its features, advantages and specific embodiments, reference is made to the following detailed description along with accompanying drawings in which:
[0021] [0021]FIG. 1 depicts a top view of a package showing an example of a preferred embodiment of the invention; and
[0022] [0022]FIG. 2 shows a cross-section view of a portion of FIG. 1 taken along line 2 - 2 of FIG. 1;
[0023] [0023]FIG. 3A illustrates a cross-section view of an alternative example of an embodiment of the invention prior to the addition of an encapsulant;
[0024] [0024]FIG. 3B shows a cross-section view of the embodiment of FIG. 3A with encapsulant added; and
[0025] [0025]FIG. 4 illustrates a cross-section view of an additional example of an alternative embodiment of the invention.
[0026] References in the detailed description correspond to like references in the figures unless otherwise noted. Like numerals refer to like parts throughout the various figures. The descriptive and directional terms used in the written description such as top, bottom, left, right, first, second, etc., refer to the drawings themselves as laid out on the paper and not to physical limitations of the invention unless specifically noted. The drawings are not to scale and some features of embodiments shown and discussed are simplified or exaggerated for illustrating the principles of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0027] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. It should be understood that the invention may be practiced with substrate bond pads and semiconductor dice of various types and materials without altering the principles of the invention.
[0028] Referring primarily to FIG. 1, a preferred embodiment of the invention is shown. A multi-layer semiconductor package 10 is made up of a first layer 14 and a second layer 12 of semiconductor material. Those skilled in the art will realize that an “encapsulating” material (not shown) has been removed in FIG. 1 to view the internal layers of the package. Those skilled in the art will appreciate that a semiconductor device may be mounted on a substrate having many layers and that the principles of the invention are not limited to the two layers shown. For example, a layer may comprise a die, lead foot, or bond pad. For the purposes of this example, one of the layers 14 is an IC die. At least one layer, in this case the second layer 12 , is provided with vias 16 . The vias 16 extend through the second layer 12 , completely perforating it from one planar surface to the opposite surface. The vias 16 may be formed by drilling (laser, mechanical, etc.), etch (chemical, dry, plasma, etc.), or other methods known to those skilled in the arts. Preferably, the vias 16 extend approximately perpendicularly through the second layer 12 .
[0029] The design is not limited to any specific geometrical shape for the vias 16 though a circular via is shown in FIG. 1. No limitations or restrictions to dimensions, aspect ratio, or placement(s) of vias is implied. The circle is used in this preferred embodiment as, in general, the circle or oval will have a cleaner fill. Those skilled in the art are aware that sharp angles, such as the corners of a square, triangle or any other n-sided polyhedra, can produce sites where poor coverage promotes voiding, introduce sites that promote trapping of plating solutions, and provide areas with higher probabilities of contamination. Sharp angles may also be sites for increased stress loci. It should be understood that the vias 16 may be provided within package 10 , bond pads 24 , lead foot areas 26 , or other substantially planar surfaces wherein a bond is desired. As shown in lead foot 28 of FIG. 1, the vias 16 may alternatively be offset to engage the edge of the planar surface, in this case the edges of lead foot 28 .
[0030] [0030]FIG. 1 depicts examples of vias 16 in two locations, the lead foot 26 , 28 , and the IC substrate 12 where the Integrated Circuit package 10 is attached to a bond pad 24 . The invention is not limited to these package types or location. Ball Grid Array (BGA) packages have a “base” to attach the die similar to the structures, e.g. bond pads, in leaded packages. As packages grow more complex incorporating dual die packages, chip scale packaging, BGA's etc., vias may be placed in a number of locations to promote strength, durability and added resistance to mechanical failure.
[0031] In addition to improving the bond integrity, the vias 16 may also serve to improve the electrical and thermal aspects of the bond depending on the attach material, since the via will be in direct contact with the die or lead foot. Since many materials have “better” properties in “preferred” directions, introducing vias may help improve electrical and mechanical properties along the preferred directions. Depending on the attach material, intermetallics can also form at the various interfaces and within the bulk of the die attach. The intermetallics, in some cases, may have inferior electrical and thermal conductivity than the individual constituent. Vias could provide a path that circumvents the “bad” IMC's but may or may not provide additional benefits in each layer.
[0032] Due to the geometries of the bond pad and leadframe, solder paste application and properties, bonding will typically occur in a lateral direction to the PC board (some perpendicular bonding will occur on the sides, front and back of the lead foot as the solder “wicks up the sides”). The area of a traditional leadframe that bonds to the board is defined as the lead foot. Conceptually, if one thinks of the letter “L” as the part of a leadframe extending from an Integrated Circuits package, the bottom part of the “L” is the area that is bonded to the PC board. That bottom portion of the “L” is referred to herein as the lead foot. Different package types may have one or more areas that serve a similar role as the “foot” in a traditional leaded package.
[0033] [0033]FIG. 2 shows a cross section taken along line 2 - 2 of FIG. 1. The vias 16 thus may provide additional 3D contact surfaces to promote stronger bonding in the direction generally perpendicular to the standard bond interface. Attach material 22 known in the art for attaching the leadfoot 26 to a surface such as a bond pad 24 is used. Vias may also be used for layer alignment based on the design. For example, vias in two or more layers may be provided for use in guiding the alignment of adjoining layers. Those skilled in the arts will recognize that many techniques may be used to induce bonds to form in the vias. For example, a full or partial vacuum may be used to flow attach material, or solder/adhesive may be placed in the vias or on the substrate prior to assembly or reflow. As another alternative, solder plugs similar to BGA balls could be added to the vias.
[0034] Referring primarily to FIGS. 3 A- 4 , in assembling the multi-layer semiconductor package 10 , the first layer 14 and second layer 12 are positioned such that their substantially planar surfaces adjoin for attaching. Preferably, attach material 22 is flowed onto the adjoining attaching surfaces of layers 12 and 14 and into the vias 16 . Thus, when the attach material 22 cures, a “3D bond” between the layers is achieved. It should be understood that the 3D bond is formed due to the provision of vias 16 in one or more layers of the package 10 . The addition of a third dimension and increase in the bonding interface provide a number of advantages further described below. It should be understood that vias may alternatively be provided in two or more adjoining layers. In such cases, the locations of the vias, may be staggered or aligned, or a combination of aligned and staggered vias may be used.
[0035] Mechanically, one method to prevent a crack from propagating is to insert a stress reliever in the path of a crack. A stress reliever can be a geometrical feature, for example a hole, placed in the path of the crack. This stress reliever has the ability to absorb or redirect energy a crack needs to grow, preventing the crack from propagating. A via forms this hole, and in some cases, not only terminates a crack but can prevent the crack from initiating. A via can also form an escape path for moisture, stored VOC's, and provide relief for other stress inducers.
[0036] Overall bond strength will be directly proportional to the total surface area participating in the bond. By adding vias to the leadframe, additional surface area is created that may also contribute to bonding. Through either capillary forces, surface tension, other chemical-mechanical means, or combinations thereof, the vias can “wick” attach material into the cavity and, in some cases, through the leadframe.
[0037] [0037]FIG. 3A is a cross-section view of an alternative embodiment of the invention wherein a substrate layer 12 is provided with vias and an attached layer 14 is an IC die. As will be apparent to those skilled in the arts, the attach material 22 may be flowed into the vias 16 and between the layers 12 , 14 in order to form a 3D mechanical bond adhering the die 14 to the substrate 12 . Additional layers 18 may also be attached, either with or without vias, depending on the requirements of the specific application. An encapsulant 20 typically engulfs the finished package 10 as shown in FIG. 3B. Note that as shown in FIGS. 3A and 3B, a recessed area of additional layer 18 may be provided in order to permit the entry of attach material 22 in order to create a more secure bond. This recessed area acts as an extension of the vias and may be provided in the layer having vias, in this example the substrate layer 12 , the adjoining layer 18 , as shown, or in both locations.
[0038] In a further example of an alternative implementation of the invention, temporary layers may be used for controlling the placement of attach material at an interface. Referring to FIG. 3A, layer 18 may be temporarily placed as shown to ensure correct placement of attach material 22 , and then removed after the attach material 22 has been placed, leaving a secure bond.
[0039] [0039]FIG. 4 shows an alternative implementation of a package 10 with vias 16 in a substrate layer 12 . The attach material 22 bonds an IC die 14 to the substrate layer 12 creating a bond that includes an interface between the layer 12 , 14 , surfaces, as well as the vias 16 .
[0040] Typically vias are placed at an angle substantially perpendicular to the plane of the layers, however, other angles may be used. Solder joint failures typically run parallel to the bond interface (lateral to the PC board). By placing a bonded surface at almost perpendicular to the direction of the crack growth, further growth can be reduced if not impeded and terminated completely. Thus, by the addition of vias, a built-in-mechanism to impede crack growth and additional bonding area perpendicular to the lateral bond surfaces are provided. The solder/epoxy may wick into the via either due to capillary action, surface tension, chemical-mechanical forces such as the application of a full or partial vacuum, or any combination thereof, providing additional bonding surface between layers of the package. The additional bonding interfaces also provide more area for electrical contact pre and post any problem with the bond. Temperature profiles (time and peak temperature) may be reduced as well since less leadframe base metal (reduction in overall leadframe mass due to missing material in the vias) will be present to consume heat from the reflow or curing operation.
[0041] General practice is to hold the peak temperature during reflow (solder) around −30° C. above liquidus temperature for some time X that is determined based on a number of factors such as board density, board size, atmosphere, package types populating the board, etc., to achieve reliable solder joints.
[0042] A typical reflow cycle exposes the board and the components to a pre-heat prior to the actual reflow portion of the cycle. A number of factors contribute to the actual peak temperature of liquids during the reflow cycle. Since the primary goal is to reflow the solder to form a strong mechanical, chemical, and/or chemical-mechanical bond between the solder and lead, the less heat required into the system to achieve this bond will save process cycle time and cost. A leadframe consumes some heat prior to reflow. This heat consumption depends on the mass of the leadframe, any conduction to attached surfaces or structures such as the package body mold compound, die, die attach, die pad, etc., and the starting temperature of the leadframe. Reducing the mass of the leadframe helps to reduce the time and temperature necessary to achieve the reliable bond and allows one to optimize the overall process cycle time and temperature input variable.
[0043] By introducing vias into the leadframe, a fixed mass of material is removed from the leadframe. The net result may be less heat required to bring the leadframe to reflow temperatures. Higher temperature's may also be unnecessary, as stated previously, due to improved bonding as the molten solder fills the vias to form additional bond sites. The vias also provide additional bond strength. Reductions in fillet area may also permit higher lead densities.
[0044] Any number of factors control the maximum semiconductor devices that can be placed on a PC board (PCB). Shorts between package leads cause a number of failures in PCBs. Wicking, one culprit, has a root cause that can be attributed to lead profiles, (the geometrical shape of the lead, length, aspect ratio, or the spacing between centerlines of adjacent leads). Lead geometries and “un-optimized” processes can impose restrictions on the minimum size of current packages.
[0045] Vias have the potential to reduce wicking, allowing an optimization of the spacing between leads can be optimized. This optimization allows closer spacing of leads and may provide a potential to reduce overall package dimensions and geometries. This reduction in Integrated Circuits package geometry also allows the PCB to become smaller. Thus, the invention provides advantages in stronger and improved failure-resistant bonds resulting in increased reliability, performance, and a potential reduction in the amount of attach material needed for bonding and a reduction in lead and package size.
[0046] The embodiments shown and described above are only exemplary. Additional applications for the invention may be made, for example, components such as chip capacitors and resistors could benefit from this invention by modifying the terminations. Changes to the current end terminations could be improved by incorporating features that allow vias to be used. These vias could have similar benefits as failures in these components can occur due to similar items such as stressed solder joints and incomplete electrical contacts. Minimum fillet size requirements could also be improved with the addition of vias. In all cases, the via could be pre or partially filled prior to mounting.
[0047] Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description together with details of the method and device of the invention, the disclosure is illustrative only and changes may be made within the principles of the invention to the full extent indicated by the broad general meaning of the terms used in the attached claims. | Disclosed are semiconductor packages and methods incorporating the use of vias in layers of leaded and nonleaded multilayer packages. The vias provide fluid communication between layers such that bonding material flows among layers for the formation of a 3D bond. As disclosed, the layers may comprise leads, dice, bond pads, or other substantially planar semiconductor package surfaces. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of enumerating Universal Serial Bus (USB) devices. Specifically, embodiments of the present invention relate to a method and apparatus for providing a necessary amount of current for enumerating a USB device.
2. Related Art
Devices that connect to a host computer by means of a USB bus may be referred to as USB devices. A USB device may be a printer, a scanner, a hard disk, a digital camera, a CD burner, etc., or any device configured to connect to a host system or device via a USB bus. Enumeration is the bus related process by which a USB device is attached to a system and is assigned a specific numerical address that will be used to access that particular device. It is also the time at which the USB host controller queries the device in order to decide what type of device it is in order to attempt to assign to it an appropriate driver. This process is a fundamental step for every USB device because, without it, the device would never be able to be used by the operating system.
Until recently there were two classifications of USB devices, low speed devices and full speed devices. During the initial enumeration process, during which it identifies itself to the host and obtains an address, the device draws current from the V-bus line of the USB bus. A USB specification states that this current should not exceed 100 mA during enumeration. The low speed and full speed devices have had no trouble meeting the 100 mA specification. Once the initialization of the enumeration process is complete, the USB device may request to draw up to 500 mA, and may do so once the host has granted permission.
Recent USB devices have been manufactured that operate at higher speeds (High-Speed USB) than the full speed devices and, as a result, they may draw current in excess of 100 mA during the initial process of enumeration. Manufacturers of high speed USB devices are finding it difficult to manufacture such a device that runs at less than 100 mA during the initial enumeration process. The consequence is that many manufacturers are having problems getting USB certification for their products or are producing products that are draining excess battery power from laptop computers or other wireless host devices in violation of the USB specification 2.0.
SUMMARY OF THE INVENTION
Accordingly, it would be desirable to have a method or device for enumerating a high speed USB device while meeting the USB specification for drawing no more than 100 mA from the USB bus during the initial enumeration process.
According to embodiments of the present invention, USB enumeration architecture is provided herein that is compatible with the power specifications for a USB while able to enumerate high speed USB devices needing power in excess of the USB specifications.
In various embodiments, a Universal Serial Bus (USB) device enumeration architecture is described herein comprising a USB bus for supplying a current during the USB device enumeration, a current mixer coupled to the bus, and a chargeable power source coupled to the USB bus. The USB bus is configured to charge the chargeable power source during a first time interval. Then, the chargeable power source is configured to discharge a current during a second time interval, the discharged current being mixed with the current from the USB bus for enumerating a USB device. In this fashion, the present invention allows the USB device to consume more power than the USB specification calls for during enumeration with the excess coming from the chargeable source. In this embodiment, the second time interval corresponds to the enumeration phase.
In one embodiment, a USB device architecture is described that further comprises a current regulator coupled to the USB bus for regulating current supplied to the USB device from a host device. A state machine implemented control circuit may also be used.
A USB device architecture is described, according to one embodiment, including control logic for switching from charging to discharging the chargeable power source following the first time interval. In one embodiment, a USB device architecture is described wherein the control logic comprises a timer for determining the first time interval. A USB device architecture is described, in accordance with one embodiment, further comprising a resistor for connecting the chargeable power source to the current mixer and the architecture to the USB device.
In one embodiment a method for enumerating a USB device is also described wherein a chargeable power source is provided and coupled to a USB bus. The power source is charged during a first time interval with current from the USB bus and the power source is discharged during a second time interval. The resultant discharge current augments the current from the USB bus, thus providing sufficient current for enumerating a high speed USB device.
The present embodiments provide the above advantages and others not specifically mentioned above but described in the sections to follow. Other features and advantages of the embodiments will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention:
FIG. 1A is a block diagram of an overview of a timeline for the steps in enumerating a USB device in accordance with one embodiment of the present invention.
FIG. 1B is a block diagram of the specified current limits for a USB bus integrated with the block diagram of FIG. 1A , according to an embodiment of the present invention.
FIG. 1C is a block diagram of a method of supplementing USB current integrated with the block diagram of FIGS. 1A and 1B , according to an embodiment of the present invention.
FIG. 2 is a block diagram of USB device enumeration architecture, according to one embodiment of the present invention.
FIG. 3 is flow diagram of a method for augmenting current for enumerating a high speed USB device in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
In the following detailed description of the embodiments, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one skilled in the art that the present invention may be practiced without some specific details or with equivalents thereof. In other instances, well-known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the embodiments.
In accordance with the embodiments, a USB device enumeration architecture is designed using a chargeable power source for augmenting USB bus current for enumerating a USB device. The USB device enumeration architecture includes a chargeable power source that may be charged from the USB bus current during a first time interval and, subsequently, discharged to augment the USB bus current during a second time interval while the USB device is being enumerated. This allows high speed USB devices to be enumerated without exceeding the design specifications for USB busses that specify the current draw from the USB bus during enumeration remain at or below a low limit (e.g., 100 mA).
FIG. 1A is a flow diagram 100 a of an overview of a timeline for the steps in enumerating a USB device according to one aspect of the embodiments. In block 110 , a USB device is plugged into a USB port, e.g., of a hub or host computing device, like a laptop computer. The USB device may be a low speed, full speed or high speed device. It may be any of a variety of devices configured to attach to a host computing device (e.g., a computer) by means of a USB port.
Block 115 of diagram 100 a represents a first time interval, t 1 , during which a chargeable power source, such as a capacitor or a battery, is charging from current supplied by a v-bus within the USB bus in accordance with an aspect of the embodiments. Time, t 1 , may vary depending on design parameters, but might be expected to be of a duration of approximately 100 milliseconds (ms). During time t 1 , the USB device is not logically attached to the USB bus. According to one embodiment, the charge built up at the chargeable power source may be determined at the end of a predetermined time period (e.g., 100 ms) and if not sufficient for the device to be enumerated, an extension period to time t 1 (e.g., 100 ms) may be granted. This may be repeated. The chargeable power source may then continue to charge until a sufficient charge is accumulated for enumerating the device.
Still referring to FIG. 1A , block 120 illustrates the USB device logically attaching to the USB bus according to one embodiment. At this point, the chargeable power source is sufficiently charged and the enumeration architecture is set to discharge the power source. At block 120 the USB device pulls up a D+ data line from the USB bus, initializing the enumeration process.
Block 125 of FIG. 1A represents a second time interval, t 2 , according to one embodiment. During time interval, t 2 , the initial phase of the enumeration process occurs, and the chargeable power source is being discharged to supplement the specified low current limit from the USB bus when needed. Therefore, during t 2 , the USB device consumes only the specified amount (e.g., 100 mA) from the USB bus with any extra coming from the chargeable power source. Once the host device has sufficient information from the enumeration to recognize the USB device and its current and bandwidth requirements, etc., the host may issue a command that grants the USB device up to a specified high current limit (e.g., 500 mA) from the USB bus. At this point, the chargeable power source is no longer needed and the USB device may finish any portion of enumeration not completed and operate with the 500 mA for an indeterminate time period as illustrated by period t 3 of block 135 . It should be understood that the values of 100 mA and 500 mA are representative of limits in USB specifications at the time of the present application and may be any limit values within reasonable range of 100 mA and 500 mA as might be specified in any USB specification.
FIG. 1B is a block diagram 100 b of the specified current limits for a USB bus integrated with the block diagram of FIG. 1A , according to an embodiment of the present invention. Block 140 represents the duration of the specified 100 mA current from the USB bus. According to one embodiment, the 100 mA current limit (from the USB bus) is in force throughout time intervals t 1 and t 2 of FIG. 1A . That is, the 100 mA is in force until the host device grants permission for the USB device to use up to 500 mA of current as illustrated, according to one aspect of the embodiments, by block 150 of FIG. 1B .
FIG. 1C is a charging diagram 100 c for supplementing USB current integrated with the diagrams of FIGS. 1A and 1B , according to an embodiment of the present invention. Block 160 illustrates the charging of a chargeable power source (e.g., a battery or capacitor) during time interval t 1 . It should be appreciated that if insufficient charge is accumulated over a first interval t 1 , that t 1 may repeat over and over until such time as sufficient charge has accumulated at the chargeable power source.
Still referring to FIG. 1C , block 170 illustrates the discharging of power from the chargeable power source to supplement the 100 mA USB current for enumeration during time interval t 2 , according to one embodiment. At the beginning of interval t 2 , control logic (e.g., control logic 225 of FIG. 2 ) activates a pull-up resistor (e.g. 230 of FIG. 2 ) and switches (e.g., switches 240 and 235 of FIG. 2 ) are set to discharge (discharge=1) the power source for supplementing the 100 mA current. Thus, the USB device may be enumerated within the USB specifications.
FIG. 2 is a block diagram of USB device enumeration architecture 200 in accordance with an embodiment of the present invention. USB bus 210 is also shown. Device 200 includes current regulator 215 , chargeable power source 220 , control logic and attach timer 225 and attach pull-up resistor 230 , according to one embodiment of the present invention. Also included in architecture 200 , according to an embodiment of the present invention, are switches 235 and 240 (controlled by circuit 225 ), current mixer 245 and USB device 250 . Architecture 200 may, in one embodiment, reside within USB device 250 or, according to another embodiment, architecture 200 may be made available as a separate power monitor or power maintenance chip coupled to the USB bus 210 .
Still referring to FIG. 2 , USB bus 210 may be a standard USB (Universal Serial Bus) bus that is well known to those skilled in the art. USB bus 210 is designed to connect a variety of peripheral devices to a host device. Bus 210 has four lines, a voltage v-bus line, two data lines (D+ and D−) and a ground line. The specification for USB bus 210 limits the current draw of a USB device (e.g., USB device 250 ) to a low limit (e.g., 100 mA) until such time as a host device (to which the USB device is attaching via USB bus 210 ) grants permission to increase the current draw to a maximum limit (e.g., 500 mA). USB device 250 will identify itself to the host device to receive an address, a driver and configuration with the host. This process of a device identifying itself to the host and becoming configured for the host is known as enumeration. High speed USB devices frequently need in excess of the specified low limit in order to be enumerated.
Current regulator 215 of FIG. 2 is a circuit designed to regulate the current from the v-bus line of USB 210 so as not to exceed the low limit (e.g., 100 mA) during the enumeration of device 250 until such time as a host (not shown) grants permission to increase the current to a high limit (e.g., 500 mA). Current regulator 215 then regulates the current to remain at or below the specified high limit. Regulator 215 receives a control signal 217 and during enumeration this signal limits regulator 215 to supply only 100 mA and, otherwise, it may supply 500 mA.
Still referring to FIG. 2 , during the first time interval (t 1 of FIG. 1A ) when the USB device has first been plugged into the USB bus 210 , control logic circuit 225 causes switch 240 to be set to discharge=0, attaching chargeable power source 220 to current regulator 215 and v-bus of USB 210 . Signal 217 is low and 100 mA is regulated. Switch 235 remains open and the data lines of USB bus 210 are not pulled up so that USB device 250 is not attached to the circuit or the host during time interval t 1 . Control logic circuit 225 generates the charge/discharge signal 219 controlling the switched chargeable power source. During this time, as measured by circuit 225 , chargeable power source 220 is drawing current from USB 210 , as regulated by current regulator 215 . Only 100 mA maximum may be drawn at this phase.
Control logic and attach timer 225 of FIG. 2 determine the end of time intervals t 1 and t 2 , according to one embodiment. When t 1 has ended, control logic and attach timer 225 sends a signal to attach pull-up resistor 230 that pulls up data line D-plus and causes switch 240 to change to the discharge=1 position. Switch 235 closes, thus, along with the D-plus line, attaching USB device 250 to the USB bus and to the host device. Signal 217 is still low. At this time, chargeable power source 220 is available to discharge current into current mixer 245 where the USB bus current can be supplemented and mixed with the discharged current from chargeable power source 220 for enumerating USB device 250 .
In summary, during time interval t 2 enumeration is occurring and the USB device may draw more power than 100 mA with the excess deriving from the chargeable power supply 220 and the 100 mA deriving from the USB bus 210 .
At the end of time interval t 2 , when the host device has granted permission to USB device 250 to come aboard, control logic and attach timer 225 signals current regulator 215 to allow the v-bus of USB bus 210 to output up to the maximum high limit (e.g., 500 mA) current. At this time, in accordance with one embodiment, the USB device enumeration architecture has completed its task. At this time, signal 217 goes high, allowing 500 mA to be regulated by regulator 215 .
The current regulator 215 , current mixer 245 , switches 235 and 240 , chargeable power source 220 and control logic and attach timer 225 can be integrated within USB device 250 or they may be integrated within a separate power maintenance device or chip for connecting to the USB device. Control logic 225 may be implemented by a state machine.
FIG. 3 is flow diagram 300 of a process for augmenting current for enumerating a high speed USB device in accordance with one embodiment of the present invention. Although specific steps are disclosed in flow diagram 300 , such steps are exemplary. That is, the present invention is well suited to performing various other steps or variations of the steps recited in FIG. 3 .
At step 310 of FIG. 3 . A USB device (e.g., USB device 250 of FIG. 2 ) is plugged into a USB bus (e.g., USB bus 210 of FIG. 2 ). During a first time interval t 1 after the USB device has been plugged into the USB bus, USB device 250 is not attached to the circuit or the host.
At step 320 of FIG. 3 , a chargeable power source (e.g., chargeable power source 220 of FIG. 2 ) is drawing current from USB bus 210 , over a time interval t 1 . At the end of time interval t 1 , step 330 is entered and USB device 250 is attached to the host device through USB bus 210 and enumeration architecture 200 and enumeration is begun in accordance with one aspect of the embodiments, provided there is sufficient current available. If there is insufficient current at any point during step 330 , step 340 of process is entered and the process returns to step 320 for further charging of the chargeable power source. This step may be repeated as often as necessary until step 350 may be entered.
At step 350 , according to one embodiment, the host device has completed the initial enumeration process and allocates the USB device permission for the higher USB current limit so that it may be fully attached. At this point the chargeable power source and the USB enumeration architecture are no longer needed and the process exits flow diagram 300 .
The foregoing descriptions of specific embodiments have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. | A method and device for supplementing current from the USB bus for enumerating USB devices that require additional current beyond that allowable by USB bus specification. A chargeable power source, such as a capacitor or rechargeable battery, is supplied to the enumeration circuitry and is charged from the USB bus for an initial period of time. The charged power source is then discharged to supplement the allowable current available for enumeration during a second period of time. It is during this second period of time that the enumeration takes place. The circuitry may exist in the USB device or may be supplied separately as a power monitor or power maintenance chip or device. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/708,323 filed on Oct. 1, 2012.
TECHNICAL FIELD
The present invention relates generally to a system and method for improving combustion stability and reducing emissions in a gas turbine combustor. More specifically, the improvements in a combustor premixer address acoustic dynamic instabilities and can also reduce thermal stresses, thus improving structural integrity and component life.
BACKGROUND OF THE INVENTION
In an effort to reduce the amount of pollution emissions from gas-powered turbines, governmental agencies have enacted numerous regulations requiring reductions in the amount of oxides of nitrogen (NOx) and carbon monoxide (CO). Lower combustion emissions can often be attributed to a more efficient combustion process, with specific regard to fuel injector location and mixing effectiveness.
Early combustion systems utilized diffusion type nozzles, where fuel is mixed with air external to the fuel nozzle by diffusion, proximate the flame zone. Diffusion type nozzles have been known to produce high emissions due to the fact that the fuel and air burn stoichiometrically at high temperature to maintain adequate combustor stability and low combustion dynamics.
An enhancement in combustion technology is the utilization of premixing, such that the fuel and air mix prior to combustion to form a homogeneous mixture that burns at a lower temperature than a diffusion type flame and produces lower NOx emissions. Premixing fuel and air together before combustion allows for the fuel and air to form a more homogeneous mixture, which will burn more completely, resulting in lower emissions. However, in this configuration the fuel is injected in relatively the same plane of the combustor, and prevents any possibility of improvement through altering the mixing length.
Premixing can occur either internal to the fuel nozzle or external thereto, as long as it is upstream of the combustion zone. An example of a premixing combustor 100 of the prior art is shown in FIG. 1 . The combustor 100 is a type of reverse flow premixing combustor utilizing a pilot nozzle 102 , a radial inflow mixer 104 , and a plurality of main stage mixers 106 and 108 . The pilot portion of the combustor 100 is separated from the main stage combustion area by a center divider portion 110 . The center divider portion 110 separates the fuel injected by the pilot nozzle 102 from the fuel injected by the main stage mixers 106 and 108 . While the combustor 100 of the prior art has improved emissions levels and ability to operate at reduced load settings, analysis and testing has demonstrated the onset of thermo acoustic dynamics due to symmetries generated in the burner as a result of the burner geometry, such as the center divider portion.
As one skilled in the art understands, mechanisms that cause thermo-acoustic instabilities are coherent structures generated by the burner. One type of combustor known to exhibit such instabilities is a combustor having a cylindrical shape. What is needed is a system that can provide flame stability and low emissions benefits at a part load condition while also reducing thermo-acoustic instabilities generated by coherent flame structures.
SUMMARY
The present invention discloses a gas turbine combustor having a structural configuration proximate a pilot region of the combustor which seeks to minimize the onset of thermo acoustic dynamics. The pilot region, or center region of the combustor, is configured to incorporate asymmetries into the system so as to destroy any coherent structures in the resulting flame.
In an embodiment of the present invention, a combustor is disclosed having a combustion liner located within a flow sleeve with a dome located at a forward end of the flow sleeve and encompassing at least a forward portion of the combustion liner. The combustor also comprises a generally cylindrical extension projecting into the combustion liner from the dome, where the outlet end of the extension has an irregular profile.
In an alternate embodiment of the present invention, an extension for a dome of a gas turbine combustor is disclosed. The extension comprises a generally cylindrical member extending along an axis of the combustor where the generally cylindrical member has an outlet end configured to not be located in a single plane perpendicular to the axis of the combustor.
In yet another embodiment of the present invention, a method is provided for isolating a main stage of fuel injectors from a pilot fuel nozzle in order to reduce acoustic dynamics in the combustor. The method comprises providing a combustion liner having a dome and extension component where air is injected into the combustion liner and a first stream of fuel is injected into the extension piece to mix with a portion of the air to form a pilot flame. A second stream of fuel is injected into another portion of the air located outside of the combustion liner. This mixture is then directed into the combustion liner in a way such that the second stream of fuel is separated from the first stream of fuel by the extension piece.
Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The instant invention will now be described with particular reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The present invention is described in detail below with reference to the attached drawing figures, wherein:
FIG. 1 is a cross section view of a gas turbine combustion system of the prior art.
FIG. 2 is a cross section view of a gas turbine combustion system in accordance with an embodiment of the present invention.
FIG. 3 is a perspective view of a portion of the gas turbine combustion system of FIG. 2 in accordance with an embodiment of the present invention.
FIG. 4A is a detailed cross section view of a portion of the gas turbine combustion system of FIG. 2 in accordance with an embodiment of the present invention.
FIG. 4B is an alternate detailed cross section view of a portion of the gas turbine combustion system of FIG. 2 in accordance with an embodiment of the present invention.
FIG. 5 is an alternate perspective view of a portion of a gas turbine combustion system in accordance with an alternate embodiment of the present invention.
FIG. 6 is a cross section of the portion of a gas turbine combustor of FIG. 5 in accordance with an alternate embodiment of the present invention.
FIG. 7 is a perspective view of a portion of a gas turbine combustion system in accordance with yet another alternate embodiment of the present invention.
FIG. 8 is a cross section of the portion of a gas turbine combustor of FIG. 7 in accordance with an alternate embodiment of the present invention.
FIG. 9 is a perspective view of a portion of a gas turbine combustion system in accordance with an additional embodiment of the present invention.
FIG. 10 is a perspective view of a portion of a gas turbine combustion system in accordance with yet another embodiment of the present invention.
FIG. 11 is a perspective view of a portion of a gas turbine combustion system in accordance with a further embodiment of the present invention.
FIG. 12 depicts the process of isolating a main stage of fuel injectors from a pilot stage in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
By way of reference, this application incorporates the subject matter of U.S. Pat. Nos. 6,935,116, 6,986,254, 7,137,256, 7,237,384, 7,513,115, 7,677,025, and 7,308,793.
The preferred embodiment of the present invention will now be described in detail with specific reference to FIGS. 2-12 . The combustion system of the present invention utilizes premixing fuel and air prior to combustion in combination with precise staging of fuel flow to the combustor to achieve reduced emissions at multiple operating load conditions. Reconfigured combustor geometry is provided to target a reduction of combustion acoustic pressure fluctuations, to reduce thermal stresses, cracking and detrimental thermo-acoustic coherent structures.
Referring now to FIG. 2 , a gas turbine combustion system 200 is provided comprising a generally cylindrical flow sleeve 202 and a generally cylindrical combustion liner 204 located at least partially within the flow sleeve 202 . The combustion system 200 also comprises a dome 206 located axially forward of the flow sleeve 202 . The dome 206 is positioned such that it encompasses at least a forward portion 208 of the combustion liner 204 . The dome 206 also has a hemispherical head end 210 and an opening 212 that is coaxial with a center axis A-A of the combustion system 200 . The gas turbine combustion system 200 also comprises a pilot nozzle 214 extending generally along the center axis A-A of the combustion system 200 and a radial inflow mixer 216 , each for directing a supply of fuel to pass into the combustion liner 204 along or near the center axis A-A.
Referring also to FIGS. 3, 4A and 4B , the gas turbine combustion system 200 also comprises a generally cylindrical extension 218 projecting into the combustion liner 204 from the dome 206 . The precise length of generally cylindrical extension 218 can vary and is chosen based upon the operating parameters defining turndown as the main fuel stage is isolated from the pilot stage by separating the flame regions and avoiding flame quenching at lower operating temperatures. The extension 218 has an inlet end 220 positioned at the opening 212 of the dome 206 and an opposing outlet end 222 , which is positioned at a distance within the combustion liner 204 . As discussed above, combustors that have a cylindrical structure with uniform exit planes are subject to cracking due to thermal gradients causing circumferential stresses within the cylindrical structure. Furthermore, these combustors also have tendencies to produce thermo-acoustic dynamics having a coherent structure. That is, the acoustic waves formed within the combustor have a uniform structure due to the symmetric structure within the combustor. The combustor of the prior art depicted in FIG. 1 has been known to exhibit circumferential stress-induced cracking and to produce acoustic waves in the center divider portion 110 , due to its symmetric structure.
As one skilled in the art will understand, acoustic waves are a by-product of the combustion process due to vortices being shed at a cylindrical burner outlet. When these vortices are convected into the flame, a fluctuation in the heat release occurs. When the acoustic fluctuations amplify the shedding of vortices, a constructive interference with the heat release can occur causing high amplitude dynamics. These high dynamics can cause cracking in the combustor.
The present invention provides reconfigured combustor geometry to help reduce fluctuations in heat release. In the prior art combustor of FIG. 1 , the combustor 100 included a center divider portion 110 for separating the flow of fuel in the pilot nozzle 102 from the fuel from main stage injectors 106 and 108 . The center divider portion 110 has a cylindrical cross section and a uniform exit plane perpendicular to the flow of fuel and air. As such, vortices shed at the exit plane of the center divider portion 110 are convected into the surrounding main stage flame, which is produced by injection of fuel from injectors 106 and 108 . Because of the uniform exit plane of the center divider portion 110 , these vortices have been known to cause a fluctuation in heat release and cause high amplitude dynamics. Further, the large temperature gradient experienced by the center divider portion 110 creates circumferential stresses causing cracking of the divider portion.
To improve the prior art combustor design while maintaining the benefit of separate fuel injection circuits required for a combustor having the specified design and staging configuration, the outlet end 222 of the generally cylindrical extension 218 in combustion system 200 is configured to have an irregular profile or shape. An irregular profile or shape has been shown to reduce the temperature gradient and dynamics levels. A variety of irregular shapes can be used for the outlet end 222 of the generally cylindrical extension 218 . FIGS. 3-6 depict some of the alternate embodiments of the generally cylindrical extension component having an irregular profile or shape to the outlet end.
Referring to FIGS. 3-4B , the irregular profile or shape of the outlet end 222 comprises a planar edge 224 extending generally perpendicular to the center axis A-A where the planar edge 224 is interrupted by a series of semi-circular cutouts 226 . The semi-circular cutouts 226 provide a non-uniform exit plane from the generally cylindrical extension 218 . That is, as the flow exits the generally cylindrical extension 218 , it will exit into the surrounding flow at slightly different axial locations due to the cutouts 226 . As a result, asymmetries are introduced into the exit flow from the generally cylindrical extension 218 , which disrupts any coherent structures being formed that could otherwise amplify if injected in a symmetrical pattern. In addition, the semi-circular cutouts 226 tend to reduce the cracking in the generally cylindrical extension 218 by relieving circumferential stresses induced by the thermal gradients in the generally cylindrical extension 218 . The exact size, quantity and spacing of the semi-circular cutouts 226 about the outlet end 222 can vary depending on a variety of factors such as frequency of combustion dynamics that should be damped, the flow velocity, flame position, and delay times. For the embodiment of the present invention depicted in FIGS. 3-4B , twelve semi-circular cutouts 226 are equally spaced about the outlet end 222 of the generally cylindrical extension 218 . Depending on the combustor design and operating conditions, the cutouts 226 can also be positioned about the outlet end 222 in a non-equal or irregular pattern
The irregular profile or shape is not limited to semi-circular cutouts. Alternatively, the irregular profile or shape of the outlet end of the extension 218 can take on other shapes, including but not limited to, a saw tooth pattern, a plurality of rectangular cutouts, and elliptical or sinusoidal cutouts.
An alternate embodiment of the present invention is depicted in FIGS. 5 and 6 . The alternate embodiment discloses a generally cylindrical extension 600 having a different geometry than that of the cylindrical extension 218 discussed above. The generally cylindrical extension 600 has an inlet end 602 and an opposing outlet end 604 . The cylindrical extension 600 is coupled to the dome and functions similar to the prior configuration discussed above and pictured in FIGS. 2-4B . The main difference with the alternate generally cylindrical extension 600 is with respect to the irregular shape of the outlet end 604 . For the embodiment depicted in FIGS. 5-6 , the outlet end 604 forms a plane taken at an angle α relative to the center axis A-A, such that the outlet end 604 is not in a single plane perpendicular to the center axis A-A of the combustion system. As with the semi-circular cutouts in the outlet end of the cylindrical extension 218 , the angular planar cut at outlet end 604 of cylindrical extension 600 provides an alternate way of introducing asymmetries into the flow of the combustion liner.
Yet another embodiment of the present invention is depicted with respect to FIGS. 7 and 8 . This alternate embodiment discloses a generally cylindrical extension 700 having a different geometry than the embodiments discussed above. The generally cylindrical extension 700 has an inlet end 702 and an opposing outlet end 704 . The cylindrical extension 700 is coupled to the dome and functions similar to the prior configuration discussed above and pictured in FIGS. 2-6 . In the configuration depicted in FIGS. 7 and 8 , it is possible to obtain the acoustic benefits driven primarily by the configuration of FIGS. 5 and 6 , with the thermal stress reductions that can be obtained through the cutouts in the outlet end of the extension, as depicted in FIGS. 3-4B . That is, the main difference with this alternate generally cylindrical extension 700 is with respect to the irregular shape of the outlet end 704 . For the embodiment depicted in FIGS. 7 and 8 , the outlet end 704 forms a plane taken at an angle α relative to the center axis A-A, such that the outlet end 704 is not in a single plane perpendicular to the center axis A-A of the combustion system. As discussed above, the angular planar cut at outlet end 704 of cylindrical extension 700 provides a way of introducing asymmetries into the flow of the combustion liner Furthermore, and as discussed above, including a plurality of cutouts 706 in the outlet end 704 helps reduce the thermal stresses within the generally cylindrical extension 700 . Although generally semi-circular cutouts 706 are shown in FIGS. 7 and 8 , the size and shape of these cutouts can vary to include other shapes, such as, but not limited to rectangular, elliptical, sinusoidal or saw-tooth shape.
A series of alternate embodiments of the present invention are depicted in FIGS. 9-11 , where the outlet end of the dome extension portion of the present invention can take on a variety of shapes in order to target certain frequencies of combustion acoustic pressure fluctuations. These alternative shapes to the outlet end may also aid in reducing thermal stresses in the dome extension. For example, the irregular profile of outlet end may consist of a variety of geometries, such as planar edges, continuous peaks and valleys or a combination of non-uniform exit plane geometries. The spacing of the features generating these profiles may be equal about the circumference of the outlet end or unequally spaced, depending on the frequency range of combustion acoustic pressure fluctuations being targeted.
Referring first to FIG. 9 , this alternate embodiment discloses a generally cylindrical extension 900 having a different geometry than the embodiments discussed above. The generally cylindrical extension 900 has an inlet end 902 (not shown) that is coupled to the dome and functions similar to the prior configuration discussed above and pictured in FIGS. 2-8 . The generally cylindrical extension 900 also has an opposing outlet end 904 . In the configuration depicted in FIG. 9 , it is possible to obtain the acoustic benefits driven primarily by the configuration of FIGS. 5 and 6 , with the thermal stress reductions that can be obtained through the cutouts in the outlet end of the extension, as depicted in FIGS. 3-4B . That is, similar to the configuration discussed above with respect to FIGS. 7 and 8 , the main difference with this alternate generally cylindrical extension 900 is with respect to the irregular shape of the outlet end 904 . FIG. 9 depicts an outlet end 904 having a wave-like profile formed by a series of axial exit planes where the effective outlet end 904 varies axially along a length of the extension 900 . These waves have a series of peaks 906 and troughs 908 , which are essentially formed by connecting a series of axially-spaced planar cuts. The peaks 906 and troughs 908 can be uniformly spaced or non-uniformly spaced. As a result of this outlet end profile, fuel flow from the pilot nozzle mixes with the surrounding fuel-air mixture in a non-uniform and axially spaced fashion, thereby introducing asymmetries into the exit flow, which disrupts any coherent structures being formed that could otherwise amplify if injected in a symmetrical pattern.
FIG. 10 provides yet another alternative embodiment of an outlet end geometry for the extension. In this embodiment, a generally cylindrical extension 1000 has an inlet end 1002 (not shown) that is coupled to the dome and functions similar to the prior configuration discussed above and pictured in FIGS. 2-8 . The generally cylindrical extension 1000 also has an opposing outlet end 1004 . As discussed above, a profile of the outlet end 1004 can be non-uniform. This is shown in FIG. 10 , which depicts a generally cylindrical extension 1000 , where the outlet end 1004 exhibits a non-uniform profile along the axial distance forming the outlet end 1004 extends. As with the embodiment depicted in FIG. 9 , fuel flow from the pilot nozzle, which extends along a center axis, can mix with the surrounding fuel-air mixture in a non-uniform and axially spaced fashion, thereby providing a way of targeting a reduction of certain frequencies of combustion acoustic pressure fluctuations.
Referring now to FIG. 11 , a portion of the gas turbine combustion system is shown including a generally cylindrical extension 1100 having an inlet end (not shown) that is coupled to the dome and functions similar to the prior configurations discussed above and pictured in FIGS. 2-8 . The generally cylindrical extension 1100 also has an opposing outlet end 1104 . As discussed above, a profile of outlet end 1104 can be non-uniform. More specifically, the outlet end 1104 can have an outlet edge formed by multiple axially-spaced exit planes, as discussed above, but these multiple axially-spaced planes are taken at varying radii relative to the center axis of the combustor, thereby defining radial peaks 1106 and valleys 1108 in the generally cylindrical extension 1100 . That is, the generally cylindrical extension 1100 can flare radially inward or outward relative to the center axis of the combustor, as represented by arc-shaped portion 1110 of generally cylindrical extension 1100 .
The present invention also provides a way of isolating a main stage of fuel injectors from a pilot fuel nozzle such that acoustic dynamics in the combustion system are reduced. Referring now to FIG. 12 , the process 1200 for isolating the main stage of fuel injectors is depicted. In a step 1202 , a combustion liner is provided for a combustion system with the combustion liner having a hemispherical dome with an opening located therein and a generally cylindrical extension positioned at the opening and extending into the combustion liner. As discussed above, the generally cylindrical extension piece has an irregular profile or shape to the outlet end. Next, in a step 1204 , a flow of compressed air is injected into the combustion liner and around the hemispherical dome. In a step 1206 , a first stream of fuel is injected into the generally cylindrical extension piece in order to mix with a portion of the compressed air injected in step 1204 for providing a pilot flame. A second stream of fuel is injected in a step 1208 from a position radially outward of the combustion liner such that the second stream of fuel mixes with compressed air from step 1204 and the fuel-air mixture reverses flow direction upon contact with the hemispherical dome and enters the combustion liner to form a main injection flame. The extension piece serves to separate the stream of fuel for the pilot flame from the stream of fuel for the main injection flame. The irregular shape or profile of the extension piece creates asymmetries in the fuel injection location and thereby destroys any coherent structures between the pilot flame and main injection flame.
While the invention has been described in what is known as presently the preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements within the scope of the following claims. The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments and required operations will become apparent to those of ordinary skill in the art to which the present invention pertains without departing from its scope.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims. | The present invention discloses a novel apparatus and method for operating a gas turbine combustor having a structural configuration proximate a pilot region of the combustor which seeks to minimize the onset of thermo acoustic dynamics. The pilot region of the combustor includes a generally cylindrical extension having an outlet end with an irregular profile which incorporates asymmetries into the system so as to destroy any coherent structures. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 119,057, filed Feb. 6, 1980, now abandoned.
BACKGROUND OF THE INVENTION
The invention relates to novel partial esters of polyphosphoric acids such as diphosphoric acid. Previously known partial esters have not been stable due to hydrolytic decomposition resulting in formation of monophosphoric acid esters.
In U.S. Pat. Nos. 2,866,680 and 2,947,774 the formation of certain alkyl esters of di- and polyphosphates are described. The compounds were unstable and decomposed within hours or at best after a few days if refrigerated.
In U.S. Pat. No. 3,004,056, surface-active monophosphates are formed by gradual addition of solid P 2 O 5 to an excess of polyoxyalkylene ether with vigorous agitation. The specification teaches that addition of the hydroxyl compound to the P 2 O 5 is inadvisable since a tar is formed thereby and the reaction will not proceed to completion.
SUMMARY OF THE INVENTION
According to the instant invention are provided polyphosphoric acid partial esters of the formula ##STR2## wherein R is each occurrence a remnant formed by removal of a hydroxyl from a monohydroxyl compound selected from
(a) a (poly)alkylene glycol monoether of the formula ##STR3## where R 1 is hydrogen, methyl, or halomethyl; R 2 is C 1-6 alkyl or haloalkyl, phenyl, halophenyl or methylphenyl; n is an integer from 1 to 4;
(b) a phenol or halophenol; and
(c) a C 1-20 aliphatic or halogenated aliphatic monohydroxyl compound;
provided that in at least one occurrence R is selected from (a); m is an integer from zero to three, y is an integer from one to three, and q is equal to m+4-y.
The monoethers of alkylene and (poly)alkylene glycols of the previously described formula suitably include for example methyl, ethyl, propyl, n-butyl or tertiary-butyl ethers of ethylene glycol, propylene glycol, (poly)ethylene or (poly)propylene glycols.
The phenol or halophenols include for example mono- and polyhalogenated phenols such as chloro- and bromophenols.
The C 1-20 aliphatic monohydroxyl compounds include common alkanols and halogenated derivatives thereof and unsaturated monohydroxyl compounds such as hydroxy-substituted alkenes, alkynes and halogenated derivatives thereof.
Preferred are diesters of diphosphoric acid, compounds of formula I wherein m is zero, R is selected from (a), and q and y are both two.
The compounds or neutral ammonium or alkali metal derivatives thereof are useful as corrosion inhibitors for functional fluids such as heat and pressure transmission fluids, and as fire-retarding agents for cellulosic materials.
DETAILED DESCRIPTION OF THE INVENTION
The invented compounds may be formed by the reaction of a monoether of a (poly)alkylene glycol optionally in combination with the phenol, halophenol or C 1-20 aliphatic or halogenated aliphatic monohydroxyl compounds with phosphorus pentoxide. Alternatively the monohydroxyl compounds may be reacted in sequence. Remnant acid functionality is assured by reacting a stoichiometrically limited amount of the monohydroxyl compound. Preferably in order to assure the presence of at least some (poly)alkylene glycol monoether remnant in each molecule of the reaction product, at least one quarter mole of (poly)alkylene glycol monoether is reacted with each mole of P 2 O 5 . The reaction technique is well-known being similar to that disclosed in U.S. Pat. No. 2,866,680. Accordingly, the monohydroxyl reactant is controllably added to a slurry comprising phosphorus pentoxide and an organic solvent such as the lower alkanes, aromatics, or halogenated hydrocarbons. A preferred solvent is dichloromethane.
To compensate for possible water contamination of the monohydroxyl reactant, excess P 2 O 5 is preferably utilized. The ratio of monohydroxyl compound remnant to phosphorus in the reaction product is desirably about 1:1.
The exothermic reaction causes heating of the reaction mass. Proper choice of a solvent allows the reaction to be maintained at a gentle reflux at moderately elevated temperatures less than about 150° C. The reaction may be continued for several hours or longer until the P 2 O 5 is substantially completely reacted. Additional heating during the course of the reaction may be accomplished by conventional means.
The product, generally a light colored liquid, may be separated from any excess unreacted P 2 O 5 by decanting or filtration, and the solvent removed if desired by evaporation or other technique.
When prepared according to the foregoing process, the resulting reaction product is obtained in high yield. Contaminants consist primarily of monophosphate reaction products, present preferably in an amount less than 10 percent by weight. Purification of the desired reaction product may be easily accomplished by chromatographic separation techniques well-known in the art. For most applications however, such purification techniques are not desired and minor contamination with reactants and monophosphate esters is acceptable. Preferably the product comprises at least 75 percent, most preferably at least 90 percent of the polyphosphoric acid partial esters of formula I.
Because the hydroxyl and alkoxy moieties of the invented compounds are known to be labile, the reaction product is more correctly described as an equilibrium mixture of compounds of generic formula I. Individual components of such mixture may have more or less than two hydroxyl moieties but on average the product mixture maintains an R:P ratio of about 1:1. When added to hydroxyl- or monoether-containing solvents, such as may commonly be found in functional fluids, the product may for this same reason exist in an equilibrium mixture. For example, interchange of alkyl monoether moieties is observed when the monoether-containing solvent is different from that employed in the initial formation of the compounds.
SPECIFIC EMBODIMENTS
The following examples are provided as further illustrative of the present invention and are not be be construed as limiting.
EXAMPLE 1
To a reaction flask containing 500 ml CH 2 Cl 2 under nitrogen atmosphere, phosphorus pentoxide (270 g, 1.9 moles reagent grade) was added with stirring. Over approximately 2 hours ethylene glycol n-butyl ether (425 g, 3.6 moles reagent grade) was added from a dropping funnel. The reaction caused gentle reflux. After complete addition only a small amount of unreacted P 2 O 5 remained and the flask contained a clear yellow colored solution. Analysis by 31 P nuclear magnetic resonance spectroscopy indicated the product comprised greater than 90 percent of the diphosphoric acid half ester with minor amounts of other partial esters of polyphosphoric acids, plus monophosphates and full ester contaminants.
EXAMPLE 2
The reaction conditions of Example 1 were repeated except that the glycol ether utilized was 1-methoxy-2-propanol added to P 2 O 5 in a molar ratio of about 1.9:1. The product recovered was primarily the diester of diphosphoric acid having the empirical formula H 2 P 2 O 5 (OCH(CH 3 )CH 2 OCH 3 ) 2 .
EXAMPLE 3
A portion of the product produced in Example 1 was neutralized by bubbling dry NH 3 into the solution at a rate sufficient to cause a gentle reflux. After about 90 minutes no further exotherm occurred indicating the reaction was complete. The solution was further diluted with CH 2 Cl 2 to a concentration of 15 percent by weight and used to treat several small strips of 1/4" fir plywood, 1/2" wide and 3" long. After immersion in the solution for between 2 and 8 hours, the strips were dried at 100° C. for about 4 hours and humidified at normal room conditions for two days. When clamped at a 45° angle and ignited for 15 seconds with a bunsen flame, all the treated strips self-extinguished in an average of less than 20 seconds. By comparison, untreated strips subjected to the same procedure are entirely consumed. | Glycol ether partial esters of the formula ##STR1## where R is a specified substituent formed by reaction of monohydroxyl reactants of (poly)glycols with phosphorus pentoxide. | 3 |
BACKGROUND OF THE INVENTION
This invention relates to the dry distillation of overworn discarded rubber tires of vehicles and more particularly to a process and apparatus for continuously and smoothly dry distilling discarded tires thereby to recover gases and liquids for combustion.
As a consequence of the rapid development of motorization in recent years, there has been a tremendous increase in the rate at which overworn or worn-out rubber tires (hereinafter referred to simply as tires) of land vehicles are being discarded. Of these tires, one portion is being reutilized as retreaded tires, but most of the tires are being disposed of as refuse. Because of the shape and bulk of tires, however, they cannot be disposed of as they are as filling material for land reclamation and other purposes, and, in some instances as a stopgap lawful method of land reclamation, tires are being cut up into pieces of suitable size and then used as filling material.
Another method of disposal of such tires is the combustion thereof. On a small scale, tires are being burned outdoors in agricultural fields and orchards for the purpose of preventing frost damage. In this case, however, the gases of combustion of rubber have a characteristic bad odor, whereby tires cannot be burned in the open except in such emergency cases. The quantity of tires used in such instances is a mere 2 to 3 percent of the total quantity of tires discarded.
On the other hand a sudden interest in the utilization of tires as a combustible material is becoming apparent as a result of the rise in energy costs. This is a natural result because of the high calorific value of tires of approximately 8,000 Kcal/kg, and already most of the tires, exclusive of those being retreaded, are beginning to be used as a substitute fuel.
However, because of structural features of tires such as their characteristic shape and steel wire incorporated therein, direct combustion of these tires requires pretreatment such as cutting and an after treatment, such as the removal of steel wires from the tires after combustion. Furthermore, because of the characteristicly high surface density of rubber, the degree of contact of the rubber with air for combustion is small, whereby incomplete combustion tends to occur, and black smoke and unpleasant odors are easily given off. Combustion of tires in large quantities is difficult in actual practice without the use of large furnaces affording long combustion zones.
As another approach, it is also possible, since combustible gases and liquid fuels can be generated by dry distilling rubber at relatively low temperatures, to once extract gas and liquid fuels and to burn them in a separate combustion furnace. In this case, the steel wire and other solids are left as residue and separated, and even if the distillation furnace and the combustion furnace are installed in a spaced apart relation, continuous operation is possible by merely connecting them with transfer piping for gaseous and liquid fuels, whereby effective utilization is readily attainable.
Accordingly, numerous techniques relating to the dry distillation of tires have heretofore been disclosed and proposed. For example, Japanese Patent Publication Nos. 25874/1978 and 27752/1978 disclose apparatuses in each of which vertical preheating and dry distillation furnaces are coupled in a gas-tight manner, and, for horizontally stacking tires therein to carry out preheating and dry distillation, respectively, and means for horizontally, handling each tire for charging the tires and removing the residue must be installed. In the operation of each apparatus, preheating and dry distillation proceed as the tires being processed in the furnaces descend one at a time, being continually maintained in horizontal state, and finally the non-volatile residue is taken out.
In a furnace of this known character, support of the tires in an orderly disposition is maintained within the furnace by a tire supporting mechanism comprising a forkshaped tire receptacle provided near the bottom of the furnace and functioning as a movable grate. In the dry distillation furnace described in Japanese Patent Publication No. 27752/1978, a butterfly-shaped grate is separately provided below the support fork to function cooperatively in supporting the tire charged into the furnace and in taking out the dry distillation residue. However, after a long period of operation of these apparatuses, problems tend to arise in the taking out of the residue.
Still another proposed furnace is of a construction wherein the inner diameter of the vertical furnace is made greater than the outer diameter of the tires at the upper part of the furnace and is tapered to become smaller than the tire outer diameter at the lower part of the furnace, and this constricted lower part is caused to exhibit a grate effect to support the tires charged into the furnace. Since there are no support structures such as a grate in the interior space of this furnace, there is little possibility of substances such as residue and semi-molten material formed in the high-temperature part of the furnace being caught or adhering to parts of the furnace, and it would seem that the operation can be expected to proceed under considerably favorable conditions.
However, this furnace has a drawback in that it is difficult to take out scrap wire after completion of dry distillation and incompletely distilled residual tires frequently produced in actual operation because of the constriction at the lower part of the furnace. Particularly in the case of continuous operation, which almost always means operation over a long period, there is a continuous accumulation of residue at the bottom of the furnace, whereby removal of this residue tends to become difficult.
In the case of batch-wise operation, it is possible, upon the completion of dry distillation of each batch, to take out the residue, including scrap wire, and carbon particles adhering to various interior parts of the apparatus as described hereinafter. This work, however, is extremely troublesome and requires much time and labor. Furthermore, a batch-wise operation unavoidably entails periodic interruptions thereof, whereby a stable operation under steady conditions cannot be achieved.
In view of the above described circumstances in the state of the prior art, we have carried out a detailed analysis of the phenomena occurring within a dry distillation furnace of the instant character during operation in order to facilitate the taking out of the dry distillation residue. As a result, from a completely separate line of thinking, we have arrived at the conceptual conclusion that the cross-sectional area of the furnace at its lower part should be made the same as or greater than that of its upper part. Furthermore, we have carried out tests based on this concept, as a result of which we have succeeded in developing this invention.
More specifically, we have carried out studies on the premises:
(1) that, within a furnace reaching a high temperature, mechanisms which can become obstructions to the falling or downward movement of charged material must be eliminated as much as possible;
(2) that, since continuous operation is the general rule, mechanisms such as that for holding charged material and that for taking out residue, which are used only at the starting and stopping of operation must be dispensed with and substituted by a mechanism for continuous operation which is most easy to control and, moreover, is efficient for ordinary continuous operation; and
(3) that, for facilitating of tire charging and for uniformity of heat distribution within the furnace, the tires charged into the furnace must be stacked in random directions.
As a result, we have found that, during steady operation, the charged tires, the residue of these tires, and the like, while combining naturally to form suitable gas passages within the furnace, brake and retard the charged material in the upper part of the furnace, whereby not only is a grate unnecessary, but since the combined mechanism progressively varies, it is useful in the stabilization of the furnace condition. Moreover, since the dry distillation residue is predominantly steel wire, it is extremely bulky, and if there are some obstructions within the furnace, this steel wire is readily caught thereby, whereby the taking out of the residue is hindered.
Therefore, it was verified that expanding the furnace cross-sectional area in the downward direction is desirable for facilitating the work of taking out the residue, that at least there is absolutely no necessity of constricting the lower part of the furnace relative to its upper part, and that, if the lower diameter is smaller than the upper diameter, trouble occurs frequently during the work of taking out the residue.
It was confirmed further that when the inner diameter of the furnace is made constant or is downwardly expanded, bridging blockage or a so-called log-jamming effect of the charged tires as they naturally fall or move downward is prevented, and that, in addition, the charged tires are automatically restacked as they sink while they are dry distilled and burned, whereby uniform reaction is facilitated, and the solid materials exhibit an effect of forming their own grate. These effects cannot be obtained in systems wherein tires are charged horizontally one at a time.
On the basis of the above described findings and conclusion, we have developed a process and furnace for continuously dry distilling tires over long periods of time. However, still another problem must be solved before this continuous and long-period dry distillation of tires can be profitably practiced. That is, one hindrance to the continuous and long-period distillation of tires has heretofore been the presence of a great quantity of dust particles, comprising principally carbon particles, in the gases generated in and discharged from the tire dry distillation process step.
More specifically, oils produced in the dry distillation adhere to these dust particles (hereinafter referred to as carbon) to form sticky carbon, which adheres to the inner wall surfaces of the apparatus and parts such as complicated bent parts and gas passages and, upon accumulating, gives rise to various difficulties such as clogging of passages. Accordingly, we have developed an apparatus for dry distilling tires which can be operated continuously and over long periods under stable conditions within the dry distillation furnace, and in which removal of adhering carbon can be accomplished without stopping the operation of the apparatus.
SUMMARY OF THE INVENTION
According to this invention in one aspect thereof, there is provided a process for the dry distillation of discarded tires which comprises charging the tires into the upper part of a vertical furnace to cause the tires to descend progressively, causing the lower tires to undergo oxidation combustion, dry distilling the upper tires with the resulting combustion gases, and collecting gaseous fuel and/or liquid fuel thereby distilled. The invention is characterized in that the tires are charged and stacked in a random state and thus caused to descend through the furnace whose horizontal cross-sectional area of its interior at its lower part is at least equal to those at higher parts of the furnace, the descent of the tires and resulting tire residue being braked by a self-formed and self-sustained grate effect until the final solid residue descends further to be discharged out of the furnace.
According to this invention in another aspect thereof, there is provided an apparatus for dry distillation of discarded tires comprising: a vertical furnace structure having an inlet opening at its top and an open lower end part; a feeding device for feeding discarded tires into the inlet opening; a leakage-sealing damper disposed in the upper part of the furnace in the vicinity of the inlet opening for preventing escape of gases to the outside through the upper part; first damper means disposed below and apart from the leakage-sealing damper for reserving the tires thus fed and subsequently dropping the same into the lower interior of the furnace structure constituting a reaction chamber, whose horizontal cross-sectional area at said lower end part is at least equal to those at higher parts of the furnace, the upper and lower parts of the reaction chamber becoming a dry distillation zone and a combustion zone, respectively, during operation, an upper chamber being thus formed between the leakage-sealing damper and the first damper means, the first damper means, when in closed state, sealing the upper chamber from the furnace interior below the first damper means; a gas discharge outlet provided at the upper part of the reaction chamber for discharging distilled gases; a tuyere disposed around the combustion zone for supplying air thereinto; burners for combustion mounted in the furnace wall in the vicinity of the tuyere for initiating combustion of the tires in the combustion zone; a water sealing device for sealing the interior of the open lower end part of the furnace structure from the outside air yet permitting residue of distillation and combustion to drop out of the furnace structure; and a residue discharging device for discharging the residue thus dropped.
According to this invention in still another aspect thereof, there is provided an apparatus as described above which further comprises a separator for separating carbon particles from the distillation gases obtained from the dry distillation in the dry distillation furnace, the separator being connected, preferably by a straight pipe, to the gas discharge outlet of the reaction chamber of the furnace and comprising: a separating device having an inlet to which the downstream end of said straight pipe is connected and operating to separate carbon particles from the distillation gases, which are then discharged through an outlet; a hopper connected to the bottom of the separating device for collecting the carbon particles thus separated; and carbon removers actuated by actuating rods of respective actuating means to remove carbon particles from the interiors of the gas discharge pipe and the separating device, respectively.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to a preferred embodiment thereof when read in conjunction with the accompanying drawings, briefly described below.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an elevational view, with parts shown in vertical section, showing the essential parts and structural organization of one example of an apparatus according to this invention by which the process of the invention can be practiced;
FIG.2 is an elevational view, with parts shown in vertical section, showing a separator for separating and removing carbon particles and oils from gases obtained by dry distillation according to the invention;
FIG. 3 is a plan view, with parts shown in horizontal section, of the separator illustrated in FIG. 2;
FIGS. 4a through 4f are elevational views, in vertical section, respectively showing different flared shapes of the lower end part of the distillation furnace structure; and
FIGS. 5a through 5d are plan views respectively showing different horizontal cross sections of the furnace lower end part at two levels.
DETAILED DESCRIPTION OF THE INVENTION
The process of dry distilling tires according to this invention can be practiced by means of the apparatus of the invention, one example of which is shown in FIG. 1. Broadly considered, this apparatus comprises a dry distillation furnace 1 and a separator 2.
The dry distillation furnace 1 has a vertical furnace structure 3 in the form of a hollow tower with a cross-sectional shape such as a circle, a square, an oblong rectangle, a polygon, or an ellipse. This furnace structure 3, the inner wall surface of which is lined with refractory material, has a constant cross-section shape and size over a greater part thereof, only its upper and lower end parts being of different shape. The lower end part 3a of this furnace structure 3 is outwardly flared and is immersed in water in a water-sealing device 4 comprising a tank holding the water. The top part of the furnace structure 3 is suitably formed to receive tires as described hereinafter and is provided with a leakage-sealing damper 5 for sealingly closing the top of the structure 3 to prevent escape of gases to the outside. The damper 5 is operated by a driving device 5a.
At an intermediate level in the upper part of the structure 3, a first pair of horizontal gate dampers 6,6, is provided to operate cooperatively across the entire cross section of the structure at that level. A second pair of horizontal gate dampers 7,7 similar to the first pair 6,6 is provided at a lower level of the structure 3. These gate dampers 6,6 and 7,7, as well as the above mentioned leakage-sealing damper 5 can be driven in their respective opening and shutting action either manually or by suitable powered driving devices 6a and 7a, respectively. The interior of the furnace structure 3 can thereby be divided into an upper chamber A between the damper 5 and the dampers 6,6, an intermediate chamber B between the dampers 6,6 and the dampers 7,7, and a lower reaction chamber C when these dampers are in closed state.
The furnace structure 3 is provided around its part enclosing the reaction chamber C with an annular tuyere 8 supplied with air for combustion from an air source 10, a group of burners 9 supplied with fuel from a fuel source for initiating combustion of tires and disposed in a horizontal circle in the furnace wall at substantially the same level as the tuyere 8, and an annular cooling jacket 12 in which coolant such as water flows. It has been found that the cooling jacket 12 serves to prevent the molten tire material from sticking to the furnace inner wall because the molten tire material is cooled by the wall and tends to solidify. A gas discharge outlet pipe 13 is provided through the furnace wall at the upper part of the combustion chamber C and is connected at its downstream end to the separator 2 described hereinafter.
A conveyor 14 is disposed at its upstream end in the aforementioned water-sealing device 4 at a position below the lower end of the furnace structure 3. The downstream part of this conveyor 14 extends obliquely upward and out of the water-sealing device 4 to a position above a solid residue collector 15 and a scrap wire collector 16.
As mentioned hereinbefore, an important feature of the dry distillation furnace in the apparatus of this invention is that the cross-sectional area of the interior of the furnace is constant or, as in the instant example thereof, expands progressively downward in the part 3a thereof below the level where dry distillation is carried out or, preferably, the level where oxidation combustion takes place. Moreover, there is no grate-like solid object for supporting the tires whatsoever within the furnace at its bottom part.
While there is no particular specification for the degree of expansion or flaring of the cross section of the furnace interior at its lower end part 3a, it should be designed in accordance with factors such as the sizes and kinds of the tires or cut-up tires to be processed. For example, in the case where a large quantity of tires having a high steel wire content are to be distilled, the furnace lower end part 3a should be widely flared. We have found, in general, that a flared lower end part 3a is desirable although in some cases a lower end part without any flare is suitable.
In general, this outward flare should be such that the angle between the inner wall surface of the lower end part 3a, as viewed in vertical section, and the vertical plumb direction is 0 to 10 degrees. By thus providing a lower end part 3a of this shape: (1) taking out of the solid residue and scrap wire is facilitated; (2) adhering of foreign matter to the inner wall surface of the furnace is prevented; and (3) "bridging" or log-jamming of solid matter across the furnace is prevented. A flare angle exceeding 10 degrees is disadvantageous because it will necessitate an increase in the sizes of the water sealing device 4 and the conveyor 14, and because it will cause excessive residue to drop onto the conveyor 14, which will make residue removal difficult.
The vertical position at which the furnace structure 3 starts to flare outward is determined in accordance with various conditions and factors. In the illustrated example, this vertical position is shown to be at the level of the cooling jacket 12. This is most desirable. However, the flared end part 3a may start at any level between a position immediately below the gates 7 and a position below the tuyere 8 and the burners 9.
The flared lower end part 3a of the furnace 3 may assume various shapes as viewed in elevation as indicated by some examples illustrated in FIGS. 4a through 4f and assume various shapes at different height levels as viewed in cross section as indicated in FIGS. 5a through 5d.
The above mentioned separator 2 connected to the downstream end of the gas discharge pipe 13 comprises, essentially, a separating device 21, which in the instant example is a cyclone separator, to whose inlet the pipe 13 is connected, a hopper 22 connected to the bottom of the cyclone 21 for extracting carbon particles, and a heat exchanger 24, to which the upper part of the central outlet tube 33 of the cyclone is connected by way of a gas discharge passage 23. The heat exchanger 24 has an outlet 24a and operates to cool and separate oils from the gases from which carbon particles have been separated in the separating device 21.
The separator is further provided with a carbon remover 26 disposed within the gas discharge pipe 13 and actuated by the actuating rod 25a of an actuating cylinder 25, an annular carbon remover 29 disposed within the cyclone 21, a carbon remover 28 disposed within the outlet tube 33, the carbon removers 28 and 29 being actuated by the actuating rods 27a, 27b and 27c of an actuating cylinder 27, and a carbon remover 32 disposed within the gas discharge passage 23 and actuated by the actuating rod 31a of an actuating cylinder 31. These carbon removers are actuated by their respective actuating cylinders to remove carbon adhering to the inner wall surfaces of their respective parts in which they are disposed.
The process of this invention is practiced by means of the above described apparatus in the following manner. Whole tires or cut-up tires are conveyed by means such as a conveyor 17 into the top part of the furnace 1. By opening the leakage-sealing damper 5, the tires thus conveyed are dropped at random onto the first pair of gate dampers 6,6.
The leakage-sealing damper 5 is provided to prevent leakage of a portion of the gases generated in the furnace which would otherwise rise, entering the chamber A as the first dampers 6,6 are opened and closed, and cause an explosion depending on the gas-air ratio. Furthermore, a tire supplying means which is relatively easy to seal from the outside air, such as a conveyor 17, is preferable. In addition, the second pair of dampers 7,7 are provided to prevent direct communication between the furnace interior and the outside air.
When a specific quantity of the tires has been supplied onto the first dampers 6,6, the operation of the conveyor 17 is automatically stopped by control means (not shown), and the leakage-sealing damper 5 is shut. Thereafter, the first dampers 6, 6 are opened, and all of the charged tires in the upper chamber A are dropped into the intermediate chamber B to rest on the second dampers 7, 7. The first dampers 6, 6 are then closed. Then, as the dry distillation reaction of the tires previously charged into the reaction chamber C progresses, and the volume of the charged tires in the reaction chamber C decreases, the second dampers 7, 7 are opened, the entire quantity of tires in the intermediate chamber B is released for shifting into the reaction chamber C.
In this case, however, since the state of filling and loading of the charged tires in the reaction chamber C is varying from second to second as the reaction proceeds, the tires in the intermediate chamber B may not entirely fall into the reaction chamber C, and a portion may remain in the chamber B in some instances. In such an event, the second dampers 7, 7 will become clogged and will not fully close, and a dangerous situation will arise if the first dampers 6, 6 are opened with the second dampers still in this clogged state. Accordingly, a safety mechanism (not shown) is provided to cause the second dampers 7, 7 to undergo repeated opening and shutting action until they can be fully closed and to prevent the first dampers 6, 6 from opening if the second dampers 7, 7 are not fully closed.
The tires which have been dropped and charged in this manner are stacked in a totally random manner within the reaction chamber C and form a self-sustaining "grate" of very high effectiveness because of the intrinsic shape of the tires.
In the initial start-up of the process, the tires are thus stacked in random state in the reaction chamber C, and, as air is fed thereinto at a suitable rate through the annular tuyere 8, the burners 9 are ignited thereby to form a combustion zone in this region from which combustion gases are generated.
When the combustion of the tires starts in this combustion zone, the burners 9 are extinguished, and only air necessary for the combustion is supplied to continue self-sustained combustion. As the oxygen in the gases generated by this combustion is consumed by combustion, the oxygen content progressively decreases below the explosion limit. As these gases rise in the furnace, they heat the charged tires and form a dry distillation zone. In general, a tire is composed of approximately 50 percent of a combustible volatile component, approximately 40 percent of a solid component comprising carbon powder, zinc white, and other solids as additives, and the remainder principally of steel wire.
One of the objects of this invention is to utilize the heat of combustion of the non-volatile carbon as energy for recovering the above mentioned combustible volatile component. Accordingly, the reaction within the furnace is carried out in a mode for achievement of this object. More specifically, in the dry distillation zone, the volatile component is vaporized by the gases of combustion at a high temperature, and the tires successively migrate into the combustion zone by dropping naturally. The remaining carbon undergoes combustion in this combustion zone due to blown in air and is used as fuel for generating combustion gases. At the same time, combustible substances other than the volatile component are burned and generate energy necessary for dry distillation. As a net result, the reaction assumes a so-called self-energy-compensation form, which is another important feature of this invention. Thus, a combustion zone and a dry distillation zone coexist within the furnace and must be maintained under mutually set conditions.
More specifically, the air for combustion is supplied through the tuyere 8 at a rate such that oxygen is supplied at a rate sufficient for the combustion of the carbon in the charged tires but not sufficient to burn the volatile combustible substances. Accordingly, only this combustion zone assumes a high temperature, and therefore the provision of the cooling jacket 12 around the outer wall at this part is effective for protecting the furnace structure 3. Within the furnace, since the dry distillation zone is formed above the combustion zone, the charged tires are heated by the combustion gases rising from below, and the volatile combustible substances are vaporized and are conducted out of the furnace through the gas discharge outlet and pipe 13.
The gases thus conducted out may be used as they are as combustion gases in a separate furnace. In addition, there are various other modes of utilizing these gases. For example, these gases are once cooled to remove heavy fractions as tar, and then, at room temperature, the light fractions and water content are separated into gaseous and liquid components which are used respectively as fuels.
Furthermore, the combustion residue in the combustion zone comprises metal wire containing a small quantity of incombustible additives and is extracted as it is from the furnace bottom. An effective method of accomplishing this is, since a load due to the tire charged into the furnace is imparted to this residue, to discharge it through the furnace bottom, for example, and to forcibly remove this residue by means of the conveyor 14.
Since the purpose of the reaction in the furnace is to accomplish dry distillation with insufficient oxygen, any leakage of outside air into the furnace is dangerous as a cause of an explosion. This danger is eliminated by making the furnace structure 3 gas-tight, providing the water-sealing device 4, and causing the pressure within the furnace to be positive.
In order to obtain a normally and steadily progressing reaction in the furnace, to take the vaporizable combustible component in a vaporized state out of the furnace while preventing as much as possible its combustion within the furnace, and, at the same time, to cause the carbon component to undergo combustion within the furnace as much as possible, it is necessary to carry out in a smooth and steady manner the charging of the tires and the taking out of the residue remaining after the dry distillation and combustion. For this purpose, one method is to provide a control system which, for example, detects the temperature within the furnace and, in response to the detection signal, causes the discharging conveyor 14 and the charging conveyor 17 to respectively start and stop.
More specifically, if the air supply into the furnace is continued with the charged tires in a stagnant state without steady downward movement, the combustion zone will progressively expand upward, and even the component to be vaporized will undergo combustion. Accordingly, there is provided a control system which detects the temperature at the upper part of the combustion zone and operates in response to the detection signal to drive the discharge conveyor 14 to take out the combustion residue and thereafter to cause newly supplied tires to be charged into the furnace.
Thus, by the process of this invention as described above: tires are efficiently processed at a high rate; gaseous and liquid fuels are continuously produced; and, moreover, and steel wire in the tires are recovered as steel scrap.
In order to indicate more fully the nature and utility of this invention, the following specific examples of practice are set forth, it being understood that these examples are presented as illustrative only and that they are not intended to limit the scope of the invention.
EXAMPLE 1
A vertical furnace having a cylindrical furnace structure (3) of a total height of 10 meters (m), a diameter at the upper end of 1.3 m, and a diameter at the lower end of 1.8 m was used. This furnace structure had first dampers (6,6) at a position 2.5 m below the top, second dampers (7,7) 1.5 m below the first dampers, a tuyere (8) for blowing in air and ignition burners (9) 1.3 m above the furnace bottom end, and a gas discharge outlet (13) 1 m below the second dampers.
The lower 0.3 m of this furnace structure was immersed in water (4) in a water tank provided at its bottom with a discharge conveyor (14) for carrying out residue. A tire feeding conveyor (17) was provided at the upper part of the furnace.
First, tires and cut-up tires were fed by the feeding conveyor (17) into the upper part of the furnace. By opening and closing the first and second dampers (6,6) and (7,7), the tires were charged into the furnace in divided lots of approximately 10 tires. When the reaction chamber (C) below the second dampers was substantially full, the charging was stopped. Air was then fed through the tuyere (8) into the reaction chamber, and, at the same time, the burners (9) were operated thereby to form a combustion zone. When this combustion chamber had been heated to a specific temperature, the burners were extinguished, and the combustion was thereafter continued by feeding only air.
As the combustion gases thus generated flowed upward through the layers of randomly charged tires, dry distillation took place, and volatile combustible substances vaporized and, together with the combustion gases, were discharged out of the furnace through the outlet and pipe (13) and into a cyclone separator (21) of the separator (2).
In the operation of feeding and charging the tires, the discharge conveyor 14 was operated intermittently every 90 seconds, and the residue was thus removed in accordance with the quantity of tires charged into the intermediate chamber (B) between the first and second dampers. Accordingly, when a space was formed at the upper part of the reaction chamber (C), the second dampers were opened to cause the tires in the intermediate chamber (B) to drop and thereby to fill the reaction chamber. Then the second dampers were closed, and the leakage-sealing damper (5) was thereafter opened to cause the tires, in a quantity corresponding to the residue removed, to drop into the upper chamber (A). The leakage-sealing damper was then closed. Thereafter, the first dampers were opened to cause the tires in the upper chamber to drop into the intermediate chamber (B), and then the first damper is closed.
The apparatus of this invention was operated continuously for 250 hours, whereupon it was found that, in terms of percent by weight of the charged tires, the quantity of the vaporized and recovered fuel was approximately 40 percent, that of the collected free solid matter was approximately 40 percent, and that of the combustion residue such as wire was approximately 10 percent. Furthermore, the unburned matter at the furnace bottom at the time of start of the operation was again charged into the top of the furnace and therefore did not require any special processing.
EXAMPLE 2
As described above, the vaporized volatile combustible substances produced by the dry distillation in the distillation furnace (1), together with the combustion gases, were discharged out of the furnace through the outlet and pipe (13) and supplied into the cyclone separator (21) of the separator (2), which had a construction substantially the same as that of the separator illustrated in FIGS. 1, 2, and 3.
In this separator, the cyclone separator operated to separate carbon particles from the gases thus supplied, and the gases thus separated and free of carbon particles were passed through the heat exchanger (24), where oils were separated from the gases.
During these separation operations in the separator, the gas discharge pipe (13) for supplying gases into the separator, the interior parts of the cyclone separator, and the gas discharge passage (23) for supplying gases into the heat exchanger were cleansed of carbon particles adhering to their respective inner wall surfaces by the carbon removers (26), (28), (29), and (32), respectively. The actuating cylinders (25), (27), and (31) for actuating these carbon removers were operated intermittently, that is, at intervals of 5 minutes, by respective timers.
It was found that even after 600 hours of continuous operation, there were no indications of malfunctioning or defects in either the dry distillation furnace or the separator, and it was obvious that the operation could have been continued much longer. This performance, which is due in part to the efficient removal of carbon by the separator, far exceeds that obtainable heretofore in the prior art, in which the limit of continuous operation has ordinarily been of the order of 72 hours.
An indirect benefit of this invention is that it affords saving of energy and does not polute the environment. That is, as mentioned hereinbefore, tires have a calorific value of 8,000 Kcal/kg, which has heretofore not been utilized in a continuous manner on a quantity-production scale. This invention affords utilization of this energy latent in discarded tires by a continuous process on a large-quantity scale. | Discarded rubber tires are charged in random state into a vertical dry distillation furnace, and the tires at a lower part thereof are caused to undergo combustion to give off hot combustion gases by which the tires at higher levels undergo dry distillation to produce distillation gases which are useable as fuel. The combustion is started by burners and is then self-sustained by supplying only air. The furnace interior at its part below the combustion zone is expanded or flared in the downward direction to an open end immersed in water, but the downward movement of the tires and residue is braked by a self-sustained grate effect until the residue finally drops out of the furnace to be removed by a conveyor. The continuous and efficient operation over a long period of this furnace is assisted by a separator also capable of long continuous operation. | 8 |
CROSS REFERENCE TO RELATED APPLICATION
The application is related to the commonly assigned: U.S. Pat. Application Ser. No. 06/734,845, filed May 15, 1985 and entitled "METHOD AND APPARATUS FOR PRODUCING A YARN", U.S. Pat. Application Ser. No. 06/773,998, filed Sept. 9, 1985 and entitled "METHOD AND APPARATUS FOR THE PRODUCTION OF A YARN", and U.S. Pat. Application Ser. No. 06/789,902, filed Oct. 10, 1985, entitled "METHOD OF, AND APPARATUS FOR, PRODUCING A YARN AND FRICTION SPUN YARN PRODUCED BY SUCH METHOD OR APPARATUS", and U.S. Pat. Application Serial No. 06/874,522, filed 6/16/86, and entitled "FRICTION SPINNING DEVICE CONTAINING A FRICTION SPINNING MEANS AND METHOD OF USE OF THE FRICTION SPINNING DEVICE.
BACKGROUND OF THE INVENTION
The present invention broadly relates to the spinning of yarn or the like according to the open end-friction spinning principle.
Generally speaking, the method of the present invention is for spinning a yarn or the like in accordance with the open end-friction spinning principle and comprises the steps of separating fibers from a body of fibers, transporting the fibers in a freely floating state by means of a pneumatic fiber transporting airstream guided in a fiber transport passage or channel in a direction of movement inclined at a predetermined acute angle to the opening of the transport passage, subsequently transferring the fibers to a moving perforated surface of a friction spinning means or element which is subjected to underpressure or vacuum, the friction spinning means or element being arranged to intercept the pneumatic fiber transporting airstream, the moving perforated surface being arranged to permit the pneumatic fiber transporting airstream to pass through the moving perforated surface, employing the friction spinning means for forming the fibers into a yarn at a yarn formation position or location, and withdrawing the formed yarn in a predetermined withdrawal direction.
The apparatus of the present invention is for performing a method for spinning a yarn and comprises means for separating fibers from a body of fibers, a friction spinning means or element having a perforated surface defining a yarn formation position or location, a fiber transport passage or channel having an exit opening situated substantially parallel to and at a predetermined spacing from the yarn formation position or location, the fiber transport passage or channel being arranged to forward the fibers pneumatically to the perforated surface for forming the fibers into a yarn, and a yarn withdrawing means for withdrawing the formed yarn.
From previous publications regarding the open end-friction spinning method, it is known to open a fiber sliver to form individual fibers by means of an opening roller known from the open end-rotor spinning method. These fibers are combed from the sliver by needles or teeth of the opening roller, which rotates at high speed. The fibers are transferred to a transporting airstream for transport to a friction spinning means or element.
The fibers in the transporting airstream are in a disordered or random state and are not stretched-out or extended. Delivering the fibers to the friction spinning means in this state, presents poor initial conditions for spinning a yarn of usable quality.
One proposal for delivering fibers in a drawn-out or extended state or condition is advanced in German Patent Publication, No. 3,324,001, published Jan. 3, 1985. In that proposal, obstacles, for example in the form of needles inclined in the fiber transport direction, are provided in the transport passage; the fibers are temporarily caught or at least braked by these obstacles. The fibers are then drawn out or extended by the airstream so as to be delivered in this drawn-out or extended state for subsequent formation of a yarn.
The disadvantage of such obstacles lies primarily in the risk that relatively large fiber clumps or conglomerations at least temporarily will form on the obstacles.
Such fiber clumps may then dislodge and be transported onwards as a unit and may then be supplied to the forming yarn end, resulting in unacceptable neps in the yarn. Another risk lies in the possibility of at least partial blockage of the transport passage or channel.
Another proposal for delivering fibers in a drawn-out or extended state, and in as parallel as possible a state or condition, into the convergent space between two friction spinning drums is set forth in German Patent Publication, No. 3,318,924, published Nov. 29, 1984. In that proposal, a slot-shaped fiber feed passage has a bulge in the region of its exit opening in the wall lying opposite the convergent space; this bulge is intended to provide the possibility for fibers delivered in a drawn-out or extended form or state to be caught at their front or leading ends by the yarn end in the convergent gap and withdrawn in the opposite direction and then to be laid parallel upon the forming yarn end in a whip-like manner with a so-called centrifugal-drawing or acceleration extension movement, so that thereafter they may be twisted into a yarn. In this arrangement, the fiber transport passage lies substantially in a plane extending through the converging gap and at right angles to the axes of the friction spinning drums or rollers. Furthermore, the fiber transport passage is inclined at an acute angle and opposite to the withdrawal direction of the yarn, for example at an angle of approximately 30° .
The disadvantage of this apparatus is that, after the front ends of the drawn-out or extended fibers have been caught by the yarn end, these fibers are diverted at the withdrawal speed of the yarn, which is relatively low compared with the fiber transport speed in the fiber transport passage, so that the trailing portion of a fiber is diverted only partially in a whip-like fashion, while the remaining portion of this fiber is subjected to longitudinal compression in the convergent gap.
Additional technology in this regard is illustrated and described in the U.S. Pat. application Ser. No. 06/773,998, filed Sept. 9, 1985, and entitled "METHOD AND APPARATUS FOR THE PRODUCTION OF A YARN", in which the fibers are delivered neither parallel nor at right angles to the yarn end but in a condition intermediate these two dispositions, so that thereafter they are twisted into the yarn end at the yarn formation position or location and are withdrawn as a yarn.
The disadvantage is, however, that in the aforementioned device of this copending United States application the irregularity with which the fibers adopt the abovementioned desired disposition is too great.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is a primary object of the present invention to provide a new and improved method and apparatus for spinning yarn which do not exhibit the aforementioned drawbacks and shortcomings of prior art constructions.
A further object of the present invention is to deliver fibers to a friction spinning means without the risks of blockage and longitudinal fiber compression, and in a substantially drawn-out or extended state or disposition of the fibers.
Yet a further significant object of the present invention aims at providing a new and improved construction of an apparatus of the character described for spinning yarn which is relatively simple in construction and design, extremely economical to manufacture, highly reliable in operation, not readily subject to break down or malfunction and requires a minimum of maintenance and servicing.
Now in order to implement these and still further objects of the present invention which will become more readily apparent as the description proceeds, the method of the present invention is manifested by the features that it comprises the steps of separating fibers from a body of fibers, transporting the fibers in a freely floating state by means of a pneumatic fiber transporting airstream guided in a fiber transport passage or channel in a direction of fiber movement which is inclined at a predetermined acute angle to the exit opening of the fiber transport passage, subsequently transferring the fibers to a moving perforated surface of a friction spinning means which is subjected to underpressure or vacuum, employing the friction spinning means for forming the fibers into a yarn at a yarn formation position or location, and withdrawing the formed yarn in a predetermined withdrawal direction. The friction spinning means are arranged to intercept the pneumatic fiber transporting airstream and the moving perforated surface is arranged to permit the pneumatic fiber transporting airstream to pass through the moving perforated surface. Importantly, the pneumatic fiber transporting airstream is supplementarily accelerated in a predetermined zone or region terminating at the exit opening and such predetermined region or zone having a predetermined height.
The apparatus of the present invention is manifested by the features that the fiber transport passage or channel has immediately before the exit opening a region with a predetermined height measured at right angles from the exit opening and in which region the fiber transport passage or channel exhibits steeper convergence than before this region and the convergence in this region has a predetermined angle.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the various figures of the drawings there have been generally used the same reference characters to denote the same or analogous components and wherein:
FIG. 1 shows a longitudinal section through a friction spinning device according to the invention, illustrated schematically and in partial section;
FIG. 2 shows a sectional partial plan view of the friction spinning device of FIG. 1 taken along the section line I--I;
FIG. 3 shows a modification of the friction spinning device of FIG. 1;
FIG. 4 shows a plan view of the friction spinning device of FIG. 3;
FIG. 5 shows a detail section of the friction spinning device according to the invention taken along the line II--II in FIG. 2 but on an enlarged scale;
FIG. 6 shows a schematic partial view of a further construction of friction spinning device according to the invention;
FIG. 7 shows a part of the friction spinning device of FIG. 6 viewed in the direction of the arrow III in FIG. 6;
FIG. 8 shows a plan view of a portion of the friction spinning device of FIG. 6; and
FIGS. 9 and 10 schematically show respective portions of the friction spinning devices of FIGS. 1, 3 and 8 on an enlarged scale.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, it is to be understood that to simplify the showing thereof only enough of the structure of the different embodiments of friction spinning apparatuses or devices has been illustrated therein as is needed to enable one skilled in the art to readily understand the underlying principles and concepts of this invention. Turning specifically to FIG. 1 of the drawings, the friction spinning apparatus or device illustrated therein by way of example and not limitation and employed to realize the method as hereinbefore described will be seen to comprise an opening roller 1 known from open-end rotor spinning techniques. The opening roller 1 is drivable and is supported in conventional manner in an only partially illustrated housing 2. This opening roller 1 is also provided in conventional manner and thus here not further described, with needles 4 or nor particularly shown conventional teeth for separating or opening a not particularly shown conventional fiber sliver into individual fibers 3.
The housing 2 is connected to a fiber feed or transport passage or channel 5 which has an exit opening 11 situated close to the cylindrical surface of a perforated friction spinning drum 6, defining a friction spinning element,. as can be particularly seen in FIG. 5.
This friction spinning drum 6 has in its interior a suction duct 7 (cf. FIG. 5), which defines by means of its walls 8 and 9 a suction zone R at the periphery of the friction spinning drum 6. In this arrangement, the walls 8 and 9 extend so close to the cylindrical internal wall 10 of the friction spinning drum 6, without contacting the internal wall 10, that inflow of leakage or false air between the walls 8 and 9 and the interior wall 10 is practically prevented.
By means of the air drawn in by the suction duct 7, and also flowing through the fiber feed passage or channel 5, the fibers 3 released by the needles 4 and while floating freely in the transport passage 5 are caught, as later region Q of the rotating friction spinning drum 6, which region Q is defined by the exit opening 11--also called simply opening 11--of the transport passage or channel 5. Finally, the fibers are twisted into a yarn 12 at a yarn formation position 13 or location.
This yarn formation position 13 is located in the region of an imaginary extension of the wall 9 of the suction duct 7 through the cylindrical wall of the friction spinning drum 6, that is in the boundary region within the suction zone R defined by the wall 9.
The friction spinning drum 6 rotates in the direction indicated by the arrow U, and thereby transports the fibers delivered in the surface region Q on the friction spinning drum 6 into the yarn formation position or location 13.
The spun yarn 12 is withdrawn by a withdrawal roller pair 14 in a yarn withdrawal direction A. As can equally well be seen from FIG. 1, the withdrawal roller pair 14 can be provided at the opposite end face of the friction spinning drum 6, as illustrated by the dash-dotted roller pair 14.1; this implies that the yarn could also be withdrawn in the opposite yarn withdrawal direction B.
The not particularly illustrated length of the suction zone R, as viewed in the direction of the yarn formation position 13, substantially corresponds to at least the length L (cf. FIG. 2) of the exit opening 11. The length L and the free breadth or width D.3 (cf. FIGS. 2, 4 and 5) of the exit opening 11 define the cross-section of the exit opening. In this context, the expression "cross-section of the exit opening" refers to the exit cross-section of the fiber transport passage 5 or channel.
FIG. 1 also shows the fiber transport passage 5 with an inclination characterized by an acute angle α. The angle of inclination α is defined between an imaginary extension of the exit opening 11 and a lower wall 16 (as viewed in FIG. 1) of the fiber transport passage 5. Furthermore, the exit opening 11 extends substantially parallel to, and is situated at a predetermined spacing a from, the yarn formation position 13.
Provided that the opposite upper wall 17 of the fiber transport passage 5 is substantially parallel to the lower wall 16, then the airstream in the fiber transport passage 5 also assumes an inclination at least similar to the exit opening cross-section.
Furthermore, FIG. 1 shows that the fiber transport passage 5 has in the region of its exit opening 11 a strongly convergent portion with the height M. As illustrated in FIGS. 2 and 5, this convergent portion converges from the passage width D.2 to the passage width D.3 of the fiber transport passage 5. The upstream portion of the fiber transport passage 5 also converges, but to a significantly lesser extent, as illustrated in FIG. 2 by the change from the passage width D.1 to the passage width D.2.
In operation, the fibers separated from the not particularly shown conventional fiber sliver by the needles 4 or the like of the opening roller 1 are taken up by the airstream Z (as will later be described in more detail) flowing past the needles 4 substantially tangentially to the opening roller 1. These fibers are transported onwards as freely floating fibers 3 in the fiber transport passage or channel 5. The airstream in the fiber transport passage or channel 5 is designated by the reference character S.
This airstream S is accelerated i.e. supplementarily accelerated in the convergent exit opening region of height M, corresponding to the change in cross-section defined by the change in the free width of the fiber transport passage 5 from the passage width D.2 to the passage width D.3. Thereafter, the fibers are taken up by the perforated friction spinning drum 6 in the region confronting the suction duct 7 (see FIG. 5).
In this acceleration zone, the airstream S is subjected to a diversion towards the cylindrical surface of the perforated friction spinning drum 6, as indicated by the curve S.1 of the arrow S. Hence, the front fiber portion, that is the fiber portion leading in the direction of flow, of a fiber 3 being delivered in such direction of flow and within such acceleration zone is also diverted in correspondence with the airstream S, and such front end of the fiber 3 is thereafter caught by the friction spinning drum 6 (as represented by the fiber orientation or condition 3.1) and is withdrawn in the longitudinal direction of the friction spinning drum 6. The trailing portion of this fiber 3 is transported further in the airstream S in the direction of the arrow N (cf. FIG. 1), and is finally delivered in a fiber orientation or disposition designated by the reference numeral 3.2 to the cylindrical surface of the friction spinning drum 6.
In this connection, the size of the angle γ (cf. FIG. 1) defining the last-mentioned fiber disposition is dependent, on the one hand, on the relationship of the speed of flow of the air before or upstream of the region of the height M of the exit opening 11 to the peripheral speed of the friction spinning drum 6 while, on the other hand, the magnitude of this angle γ is also dependent upon the height M itself, upon the supplementary or additional acceleration of the air in the previously mentioned region of the exit opening 11, and upon the angle of inclination α of the fiber transport passage or channel 5. For example, the angle γ will be smaller if angIe α becomes smaller, provided that the relationship between air speed and peripheral speed of the friction spinning drum 6 is sufficiently high, that the height M is adapted to the inclination of the fiber transport passage or channel 5 and that the supplementary acceleration in the region of the exit opening 11 is sufficiently great in order to divert the exit leading end of the respective fiber 3 sufficiently rapidly suddenly towards the cylindrical surface of the friction spinning drum 6. Basically, as the angle α becomes smaller, the relationship between air speed and peripheral speed of the friction spinning drum 6 must be increased and the supplementary acceleration in the region of the exit opening 11 must be increased due to the correspondingly lower selected value for the height M.
In practice, it has been found that the speed of the transporting air at the exit opening 11 must be at least 50% greater than the speed of the transporting air at the start of the region where the fiber transport passage 5 has a width D.2 in order to provide a sufficiently effective diversion of a leading end of the fiber 3.
Furthermore, the height of the convergent region before the exit opening 11 should not be greater than the length of the leading end of a fiber 3 taken up by this region --at the most, one third of the length of the average fiber 3 to be processed. The height M of the convergent region is therefore advantageously selected between 5 and 15 millimeters.
Furthermore, it has been established that the speed of the transporting air in the exit opening 11 should not exceed five times the speed at the region where the fiber transport passage width is D.2, that is at the start of this region. Advantageously, the speed of the transport air in the exit opening 11 lies between twice and four times the speed in the region where the fiber transport passage width is D.2.
On the other hand, it is essential that the speed of the airstream before or upstream of the convergent region be greater than the speed of movement of the friction spinning means or element, in order to avoid a situation in which the fibers 3 come to lie substantially in the direction of movement of the friction spinning means, that is extending in the peripheral direction of the friction spinning drum 6 or in the direction of rotation of a friction spinning disc 30 (see FIG. 6), as the case may be.
In a similar manner, it can be shown that the speed of the transporting airstream before or upstream of the convergent region must increase as the angle of inclination α of the fiber transport passage 5 (see FIG. 1) or 5.1 (see FIGS. 3 and 6) decreases, in order to bring the fibers 3 into the fiber orientation or disposition 3.2 with the desired angle γ. For example, if the angle of inclination α of the fiber transport passage 5 lies between 30° and 10°, the air speed should lie between 15 meters per second and 100 meters per second.
The angle of inclination γ of the fibers 3 in the fiber orientation or disposition 3.2 is also reduced if the speed of the airstream before the convergent region is increased while the speed of movement of the friction spinning means remains constant. At the minimum, the speed of the airstream must be twice as great as the speed of movement of the friction spinning means.
The angle ξ, which characterizes the degree of convergence of the convergent region, should be selected between 20° and 50°, preferably between 30° and 40°, in order to obtain the desired, previously-mentioned fiber deposition effect without excessive flow losses.
Furthermore, as illustrated in FIG. 9, the arrangement of holes 52 providing the perforation of the surface of the frictions spinning means--in this case the cylindrical surface of the friction spinning drum 6--should be selected such that the connecting lines 50 and 51 form an acute angle, the connecting lines 50 and 51 being those lines connecting hole centers which lie in an orientation or disposition inclined to the yarn formation position 13 at the respective angles β1 and β2. The larger angle β2 should not be greater than 80°, and the smaller angle β1 should not be less than 5°. Preferably, the smaller angle β1 is selected between 10° and 30°, since most fibers are deposited with this fiber disposition angle γ. Furthermore, the connecting lines 50 and 51 are provided with an inclination to the yarn formation position 13 which is opposite to that of the fiber transport passage 5 or 5.1.
It has also been established that the fibers have the tendency to lie along rows of holes on the perforated friction spinning means. This effect can be explained by the fact that the intensity of the airstream of each individual hole 52 is such that the air is able to force a fiber onto either one or another of adjacent rows of holes so that very few fibers come to rest on the friction spinning means in the regions between the rows of holes.
However, in order to obtain in practice the fiber orientation or disposition 3.2 for the fibers on the friction spinning means with the abovementioned method, the rows of holes are arranged in a disposition or distribution corresponding to this fiber orientation or disposition 3.2. In order to avoid inadvertent supply of fibers parallel to the yarn formation position or location 13, or even at right angles thereto, the rows of holes 52 are arranged such that the H straight lines 50 and 51 joining the hole centers are arranged neither parallel to the yarn formation position 13 nor at a right angle thereto.
The friction spinning device of FIGS. 3 and 4 differs essentially from that of FIGS. 1 and 2 by the disposition or spatial relation of the opening roller 1 relative to that of the exit opening 11, and also by the substantially parallel lengths or extents of the walls 18 and 19 of the fiber transport passage 5.1 defining the passage widths D.1 and D.2. Accordingly, elements with the same functions as those described for the friction spinning device of FIGS. 1 and 2 are indicated by the same reference numerals.
The fiber transport passage or channel 5.1 of the friction spinning device of FIGS. 3 and 4 has, in principle, the same function as the fiber transport passage 5 of the friction spinning device of FIGS. 1 and 2; nevertheless, since the walls 18 and 19 extend substantially parallel to one another, the fiber transport passage in the device of FIGS. 3 and 4 is designated by the reference numeral 5.1.
In the friction spinning device of FIGS. 1 and 2, the passage width D.1 corresponds to the not particularly illustrated breadth or width of the opening roller 1, while the passage width D.1 of the fiber transport passage 5.1 of the friction spinning device of FIGS. 3 and 4 can be selected independently of the breadth or width of the opening roller 1 since in this variant, said breadth or width defines the width T of the fiber transport passage 5.1.
FIGS. 6 to 8 show the use of the invention in a friction spinning device of a type known from British Patent Specification No. 1,231,198, published May 12, 1971. In that arrangement, the friction spinning disc 30 is provided in place of the friction spinning drum 6 of FIGS. 1 and 2, and a substantially conical counter-roller 31 is provided in place of a friction spinning drum 15, which would be provided in known manner as a counter-drum for the perforated friction spinning drum 6. The counter roller 31 rotates in the rotational direction F of an associated shaft 33 in order to forward into the yarn formation position or location 13 (cf. FIG. 8) those fibers 3 delivered by the fiber transport passage 5 or 5.1. The fibers 3 are twisted into a yarn 12 at the yarn formation position 13. The average spacing between the exit opening 11 and the yarn formation position 13 is designated by reference character a.1. The counter roller 31 rotates in the direction G. A suction duct 32, the suction opening of which is indicated with dash-dotted lines in FIG. 8, has the same function as the previously mentioned suction duct 7. The other elements with the same functions as those in the preceding figures are designated by the same reference numerals. FIGS. 6 and 7 indicate that the fiber transport passage 5 or 5.1 can be provided either in the manner illustrated in FIGS. 1 and 2 or in that illustrated in FIGS. 3 and 4.
In FIG. 10 and in a manner similar to that described for FIG. 9, in this case, too, the holes 52 providing the perforations are so arranged that at least two of the straight lines joining the rows of holes define an acute angle with the yarn formation position 13. These lines are designated by the reference numerals 53 and 54, respectively, and the associated angles are designated by the reference characters δ.1 and δ.2, respectively. Since the arrangement involves a friction spinning disc rather than a friction spinning drum, it is clear that the arrangement of holes must be provided in a segmental configuration as illustrated in FIG. 10.
With reference to the formation of the yarn at the yarn formation position 13 from the fibers 3 in the fiber orientation or disposition 3.2, reference is made to the aforementioned commonly assigned U.S. Pat. application Ser. No. 06/773,998.
The previously mentioned airstream Z is guided within an air infeed passage 100 extending tangentially to the opening roller 1. As indicated in FIG. 1, this air infeed passage 100 extends along a straight line into the fiber transport passage or channel 5. It is, however, possible to arrange this air infeed passage at an angle to the fiber transport passage 5. The important point is that this air infeed passage 100 be so arranged that the airstream Z is able to take up the fibers 3 from the opening roller 1 and transfer them to the fiber transport passage 5. The provision of the previously mentioned air infeed passage 100 is not limited to use in a friction spinning device according to FIG. 1 but is possible in a similar fashion in all herein illustrated fiber transport passages or channels 5.
The advantage of such an air infeed passage 100, and thus of an airstream Z, lies in the possibility of achieving in a simple manner the quantity of air required to obtain the transport speed for the fibers 3 in the fiber transport passage 5. It is also advantageous that the air flowing past the opening roller 1 can thereby be arranged to flow with a speed which is at least equal to or greater than the peripheral speed of the outermost diameter of the opening roller 1, so that the airstream Z exerts a drawing or drafting effect on the fibers to be taken up from the opening roller. In this way, there is the possibility that the fibers 3 fed to the acceleration zone in the region of the exit opening 11 have already been subjected to drawing or drafting, so that substantially stretched-out or extended fibers can be provided in the fiber orientation or disposition 3.2.
In dependence upon the selected passage form, for example a continuously convergent passage form as illustrated in FIG. 2, the air flow S can be subjected to an additional or supplementary acceleration between the opening roller 1 and the acceleration region in the exit opening 11. Thus, the front or leading fiber ends, as viewed in the transport direction of the fibers guided in the fiber transport passage 5, are also subjected a higher speed of the surrounding air than the trailing ends. This also contributes to an additional drawing-out or extension of the fibers, or at least to avoidance of crimped or kinked formations at the fibers.
Additionally, due to the simple selection of the air quantity in m 3 /min., i.e. of the flow rate the air speed in the fiber transporting passage or channel can be so selected that a desired thinning or rarefaction of the fiber flow in the fiber transport passage 5 can be achieved. This is useful for the previously mentioned diversion "somersaulting" of the fibers 3, since this somersault action becomes more effective with reduction of the number of fibers 3 in the fiber flow cross-section.
The quantity of air can be adjusted by changing the cross-section of the air infeed passage 100 or by changing the underpressure or vacuum in the fiber transport passage 5 or 5.1, respectively, or both.
While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. ACCORDINGLY, | Fibers delivered in a freely floating state in a fiber transport passage are to be laid in a predetermined disposition on a friction spinning element, such as a friction spinning drum or disc. For this purpose, an opening region of the fiber transport passage is provided with a converging portion in which the airstream is supplementarily accelerated relative to a preceding acceleration. This supplementary acceleration serves to assist in bringing the fibers into the predetermined disposition on the friction spinning drum. The friction spinning device comprises an opening roller which is rotatably supported in a housing. The housing is connected to the fiber transport passage. The opening of the fiber transport passage extends close to a cylindrical surface of the friction spinning drum. The fibers leaving the opening are transported on the friction spinning drum towards a yarn formation position where they are twisted into a yarn which is withdrawn in a selectable withdrawal direction by withdrawal rollers. | 3 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0017213, filed Feb. 26, 2008, the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to an apparatus with a liquefied natural gas (LNG) storage tank, and more particularly, to a ship with an LNG storage tank having a partitioning wall to divide the LNG tank into at least two compartments.
[0004] 2. Discussion of the Related Technology
[0005] Natural gas which is in a gas state is transported through a gas pipe line installed on the land or in the sea, or natural gas which is in an LNG state is transported by an LNG transport vessel to distant markets while LNG is stored in the LNG vessel. LNG is produced by cooling natural gas at an extremely low temperature of approximately −163° C., and a volume of LNG is approximately 1/600 of a volume of natural gas which is in a gas state, so that marine transportation is suitable for a long-distance transportation of LNG.
[0006] The LNG transport vessel, which is employed for loading LNG, sailing on the sea and unloading LNG to land markets, comprises an LNG storage tank (generally referred to as a cargo containment) which can withstand extremely low temperature of LNG. The LNG storage tank installed in the LNG transport vessel may be classified into an independent type storage tank and a membrane type storage tank depending on whether a load of cargo is directly exerted on a heat-insulating material or not.
[0007] The configuration of a membrane type storage tank is disclosed in U.S. Pat. Nos. 6,035,795, 6,378,722, 5,586,513, U.S. Patent Application Publication No. 2003-0000949, and Korean Patent Laid-open Publication Nos. 10-2000-0011347 and 10-2000-0011346. In addition, the configuration of an independent type storage tank is disclosed in Korean Patent Nos. 10-15063 and 10-305513. The foregoing discussion in the background section is to provide general background information, and does not constitute an admission of prior art.
SUMMARY
[0008] One aspect of the invention provides a floating marine apparatus comprising a liquefied natural gas (LNG) tank, which comprises: a first LNG containing compartment; a second LNG containing compartment next to the first compartment; and a bottom passage interconnecting bottom portions of the first and second compartments for fluid communication therebetween.
[0009] In the foregoing apparatus, the apparatus may further comprise a partitioning wall partitioning the LNG tank into the first and second compartments. The partitioning wall may extend from the bottom to the top of the LNG tank. The bottom passage may be formed through the partitioning wall. The bottom passage may be always open for fluid communication between the first and second compartments. The bottom passage may be sized such that a worker can pass through the bottom passage.
[0010] Still in the foregoing apparatus, the apparatus may further comprise a top passage interconnecting top portions of the first and second compartments for fluid communication therebetween. The apparatus may further comprise a partitioning wall partitioning the LNG tank into the first and second compartments, wherein the top passage and the bottom passage are formed through the partitioning wall. The top passage may be always open for fluid communication between the first and second compartments.
[0011] Further in the foregoing apparatus, the apparatus may have only one pump that is dedicated to the LNG tank for pumping to discharge LNG from the LNG tank. The LNG tank may include only one discharge outlet for discharging a liquid phase LNG from the LNG tank. The bottom passage may be sized so as to a substantial amount of LNG to flow between the first and second compartments such that the levels of LNG contained the two compartments are substantially always equalized.
[0012] Another aspect of the invention provides a floating marine apparatus, which comprises: an LNG tank; a barrier wall formed within the LNG tank and partitioning a lower portion of the LNG tank into a first compartment and a second compartment, wherein a space within the LNG tank beyond the barrier wall is not partitioned; and a bottom passage interconnecting bottom portions of the first and second compartments for fluid communication therebetween.
[0013] In the foregoing apparatus, the barrier wall may have a height lower than about half the height of the LNG tank. The barrier wall may further partition a mid portion of the LNG tank, wherein the barrier wall has a height up to about 75% of the height of the LNG tank. The bottom passage may be formed through the barrier wall. The bottom passage may be always open for fluid communication between the first and second compartments. The apparatus may have only one pump that is dedicated to the LNG tank for pumping to discharge LNG from the LNG tank. The LNG tank may include only one discharge outlet for discharging a liquid phase LNG from the LNG tank. The bottom passage may be sized so as to a substantial amount of LNG to flow between the first and second compartments such that the levels of LNG contained the two compartments are substantially always equalized.
[0014] An aspect of the present invention provides an LNG storage tank in a floating marine structure, wherein a fluid passage is formed in a structure so that it is unnecessary to increase the number of equipments to be installed for discharging LNG loaded in the LNG storage tank although an internal space thereof is divided into a plurality of spaces by the structure.
[0015] Another aspect of the invention provides an LNG storage tank installed in a floating marine structure for storing LNG therein, which comprises a structure dividing an internal space of the LNG storage tank to reduce an influence of a sloshing phenomenon caused by the LNG; and a fluid passage formed through the reinforcing structure to allow the LNG to flow therethrough. The structure may be a cofferdam or partition extending from a bottom to a ceiling of the LNG storage tank to divide the internal space of the LNG storage tank into two subspaces.
[0016] At this time, the fluid passage preferably comprises an upper fluid passage formed in an upper portion of the cofferdam and allowing boil-off gas generated during transportation of the LNG to flow therethrough and a lower fluid passage formed in a lower portion of the cofferdam and allowing the LNG to flow therethrough.
[0017] Preferably, the upper fluid passage is formed in an uppermost end of the cofferdam adjacent to a ceiling of the LNG storage tank and the lower fluid passage is formed in a lowermost end of the cofferdam adjacent to a bottom of the LNG storage tank. The lower fluid passage may have a size allowing equipments and workers for maintenance of the LNG storage tank to pass through the lower fluid passage.
[0018] In addition, the structure may comprise a protruding wall formed to protrude on a bottom of the LNG storage tank by a certain height. Here, it is preferable that the fluid passage be a lower fluid passage formed in a lower portion of the protruding wall and allowing LNG to flow therethrough. Preferably, the lower fluid passage is formed in a lowermost end of the protruding wall adjacent to a bottom of the LNG storage tank.
[0019] The structure is preferably formed in the LNG storage tank in a lengthwise direction or in a widthwise direction. The fluid passage is preferably heat-insulated to prevent heat from being transferred from outside of the LNG storage tank. Preferably, the floating marine structure is one selected from an LNG floating, production, storage and offloading (FPSO), an LNG floating storage and re-gasification unit (FRSU), an LNG transport vessel and an LNG regasification vessel (LNG RV), each of which has a storage tank for storing liquid-phase material at an extremely low temperature and floats on the flowing sea.
[0020] A further aspect of the invention provides an LNG storage tank installed in a floating marine structure for storing LNG therein, comprising: a cofferdam dividing an internal space of the LNG storage tank to reduce an influence of a sloshing phenomenon caused by the LNG, wherein the cofferdam extends in lengthwise directions of the LNG storage tank.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective view showing an external appearance of an LNG storage tank;
[0022] FIG. 2 is a transverse sectional view of an LNG storage tank;
[0023] FIG. 3 is a transverse sectional view of an LNG storage tank for a floating marine structure according to one embodiment of the present invention;
[0024] FIG. 4 is a partial sectional perspective view illustrating an interior of the LNG storage tank for a floating marine structure according to one embodiment of the present invention;
[0025] FIG. 5 is a partial sectional perspective view illustrating an interior of the LNG storage tank for a floating marine structure according to another embodiment; and
[0026] FIG. 6 is a partial sectional perspective view illustrating an interior of an LNG storage tank for a floating marine structure according to one embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0027] Hereinafter, an LNG storage tank for storing LNG in a floating marine structure according to embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
[0028] When an LNG storage tank is utilized on the sea, a sloshing phenomenon may be generated in an LNG storage tank. The sloshing phenomenon means that when a vessel plies on the sea under various sea conditions, liquid-phased material, i.e., LNG, accommodated in a storage tank is swayed. A great shock may be exerted on wall surfaces of the LNG storage tank by the sloshing.
[0029] FIG. 1 shows one example of an LNG storage tank 10 , in which upper and lower chamfers 11 and 12 , each of which is inclined at about 45 degrees, are formed on upper and lower portions of side surfaces of the LNG storage tank 10 in order to reduce sloshing load, in particular, lateral sloshing load, of LNG.
[0030] When LNG is partially loaded in the LNG storage tank as much as about 30 to 50% of an internal volume thereof, maximum sloshing load is exerted. Accordingly, in order to avoid such a partial loading state of the storage tank, an LNG transport vessel sails in a state where the LNG storage tank is fully filled with LNG or is completely empty by intention.
[0031] Demands for a floating marine structure such as an LNG floating, production, storage and offloading (LNG FPSO) or LNG floating storage and regasification unit (LNG FSRU) gradually increase. The LNG FPSO is the floating type maritime structure used for liquefying the produced natural gas directly on the sea, storing it in a storage tank, and delivering the LNG stored in the storage tank to an LNG transport vessel when necessary. In addition, the LNG FSRU is a floating type maritime structure, which stores LNG, which is unloaded from the LNG transport vessel, in a storage tank on the sea far away from the land and then gasifies the LNG, if necessary, and supplies the gasified natural gas to a market on the land.
[0032] Accordingly, unlike the LNG storage tank of an LNG transport vessel, in case of the LNG storage tanks provided in the floating marine structures, it would be difficult to adjust arbitrarily the amount of LNG to be stored, and thus the partial loading state of the storage tank causing the maximum sloshing load may not be avoided.
[0033] FIG. 2 illustrates another potential method for reducing the sloshing load. As shown in FIG. 2 , particularly in an LNG FPSO or LNG FRSU, in order to reduce an influence caused by the sloshing, it is considered that a cofferdam 15 is installed in the LNG storage tank 10 to divide the internal space of the LNG storage tank into a plurality of spaces.
[0034] However, in a case where the cofferdam 15 is installed in the LNG storage tank as described above, since the internal space of the LNG storage tank is divided into the independent spaces, pipe lines and equipments, such as pumps or pump towers for discharging LNG loaded in the LNG storage tank to the outside, would be installed separately in the respective independent spaces. Also, there are problems in that a manufacturing cost for the LNG storage tank is increased and the operation and management of the LNG storage tank become complicated.
[0035] A floating marine structure mentioned herein includes a structure and a vessel, each of which has a storage tank for storing liquid-phase material such as LNG at extremely low temperature and floats on the flowing sea. For example, the floating marine structure comprises a structure, such as an LNG floating, production, storage and offloading (LNG FPSO) or an LNG floating storage and regasification unit (LNG FSRU), as wells as a vessel, such as an LNG transport vessel or an LNG regasification vessel (LNG RV).
[0036] FIG. 3 is a transverse sectional view of an LNG storage tank for a floating marine structure according to one embodiment of the present invention, and FIG. 4 is a partial sectional perspective view illustrating an interior of the LNG storage tank for a floating marine structure. And, FIG. 5 is a partial sectional perspective view illustrating an interior of the LNG storage tank for a floating marine structure according to another embodiment.
[0037] As shown in FIGS. 3 to 5 , an LNG storage tank 20 according to one embodiment of the present invention comprises a cofferdam 25 dividing an internal space thereof into a first space 21 and a second space 22 in order to reduce an influence caused by a sloshing phenomenon of LNG received therein.
[0038] Here, in a case where the LNG storage tank is a membrane type storage tank, the cofferdam is utilized as a structure which divides the internal space of the LNG storage tank into two spaces. Also, in a case where the LNG storage tank is an independent type storage tank, a partition may be utilized as a structure which divides the internal space of the storage tank into two spaces. Hereinafter, it will be described that the LNG storage tank is the membrane type storage tank and the cofferdam is employed as a structure for dividing the internal space into two spaces, but not limited thereto.
[0039] According to one embodiment, at least one upper fluid passage 27 and at least one lower fluid passage 28 are respectively formed through upper and lower portions of the cofferdam 25 . The upper fluid passage 27 and the lower fluid passage 28 allow the first space 21 and the second space 22 in the LNG storage tank 20 to communicate with each other.
[0040] The upper fluid passage 27 is to enable boil-off gas (BOG) naturally generated during transportation of LNG to flow therethrough, and the lower fluid passage 28 is to enable LNG to flow therethrough.
[0041] According to one embodiment of the present invention, the upper fluid passage 27 enable BOG that is a gas phase to flow between the first space 21 and the second space 22 in the LNG storage tank 20 therethrough. Here, the upper fluid passage 27 is preferably formed at the uppermost end of the cofferdam 25 , that is, at a portion adjacent to a ceiling of the LNG storage tank 20 in order to enable all the BOG in the LNG storage tank 20 to be discharged, even if the LNG storage tank 20 is provided with only one facility such as a gas dome (not shown) which can discharge the BOG to the outside according to internal pressure of the LNG storage tank 20 or other reason.
[0042] In addition, according to one embodiment of the present invention, the lower fluid passage 28 allows LNG that is a liquid phase to flow between the first space 21 and the second space 22 in the LNG storage tank 20 therethrough. Here, the lower fluid passage 28 is preferably formed at the lowermost end of the cofferdam 25 , that is, at a portion adjacent to a bottom of the LNG storage tank 20 in order to enable all the LNG in the LNG storage tank 20 to be discharged, even if the LNG storage tank 20 is provided with only one facility such as a pump (not shown) and a pump tower (not shown) which can discharge the LNG stored in the LNG storage tank 20 to the outside. The number and the shape of the upper and lower fluid passages 27 and 28 may be modified appropriately according to a capacity of the LNG storage tank 20 and the like.
[0043] In addition, it is preferable that the upper fluid passage 27 and the lower fluid passage 28 be thermally insulated to prevent heat from being transferred from the outside of the LNG storage tank 20 . Any heat-insulating technique applicable to the membrane type storage tank or the independent type storage tank can be utilized as the heat-insulating method.
[0044] FIG. 6 is a partial sectional perspective view illustrating an interior of an LNG storage tank for a floating marine structure according to one embodiment of the present invention. As shown in FIG. 6 , an LNG storage tank 30 according to one embodiment of the present invention comprises a protruding wall 35 having a certain height, which is formed to protrude on a bottom of the LNG storage tank, in order to reduce an influence caused by a sloshing phenomenon of LNG received therein.
[0045] As compared with one embodiment in which the cofferdam 25 is formed from the bottom to the ceiling of the LNG storage tank to completely divide the internal space of the LNG storage tank, the protruding wall 35 in one embodiment protrudes from a bottom of the LNG storage tank by a certain height so that a lower space of the LNG storage tank is divided, but an upper space thereof is not divided. The height of the protruding wall 35 is not limited only if an influence caused by the sloshing phenomenon can be effectively reduced.
[0046] In one embodiment, the ratio of the height of the protruding wall 35 with respect to that of the LNG tank is about 0.1 to about 0.8. In certain embodiments, the ratio is about 0.1, about 0.2, about 0.3, about 0.35, about 0.4, about 0.45, about 0.5, about 0.55, about 0.6, about 0.65, about 0.7, about 0.75, about 0.8 or about 0.9. In some embodiments, the ratio may be within a range defined by two of the foregoing ratio.
[0047] According to one embodiment, at least one lower fluid passage 38 is formed through a lower portion of the protruding wall 35 . The lower fluid passage 38 is to allow LNG to flow therethrough.
[0048] In the LNG storage tank 30 , the lower fluid passage 38 formed in the protruding wall 35 allows liquid-phased LNG to flow therethrough. The lower fluid passage 38 is preferably formed at a lowermost end of the protruding wall 35 , that is, at a portion adjacent to a bottom of the LNG storage tank 30 so that all the LNG in the LNG storage tank 30 can be discharged even if the LNG storage tank 30 is provided with only one facility such as a pump (not shown) and a pump tower (not shown) which can discharge the LNG stored in the LNG storage tank 30 to the outside.
[0049] The number and the shape of the lower fluid passage 38 may be appropriately modified considering the size of the LNG storage tank 30 and the like.
[0050] In addition, it is preferable that the lower fluid passage 38 be thermally insulated to prevent heat from being transferred from the outside of the LNG storage tank 30 . Any heat-insulating technique applicable to the membrane type storage tank or the independent type storage tank can be utilized as the heat-insulating method.
[0051] In one embodiment, the protruding wall 35 may be a structure such as a partition installed merely in the LNG storage tank, or a structure obtained by modifying an external appearance of the LNG storage tank and thus changing the shape of the LNG storage tank itself.
[0052] As the storage tank in which the structure such as the aforementioned cofferdam 25 (partition in case of the independent type storage tank) or the protruding wall 35 is formed, any kind of storage tank including the independent type storage tank and the membrane type storage tank may be employed, if the storage tank can store LNG.
[0053] The structure such as the cofferdam 25 or protruding wall 35 installed in the LNG storage tank may have a cross shape as viewed from top. That is, the structure may extend in lengthwise and widthwise directions of the LNG storage tank 20 or 30 . Also, the structure may be formed to extend in only a lengthwise or widthwise direction of the LNG storage tank 20 or 30 .
[0054] The number and the size of the lower fluid passage 28 or 38 may be modified if the lower fluid passage 28 or 38 allows the LNG to flow therethrough in the LNG storage tank 20 or 30 . Also, the lower fluid passage 28 or 38 may have the size that equipments and workers for maintenance of the LNG storage tank 20 or 30 can pass through the lower fluid passage 28 or 38 .
[0055] According to embodiments of the present invention as described above, the structure such as the cofferdam, the partition or the protruding wall for restraining the sloshing phenomenon from occurring is provided in the LNG storage tank, so that although the internal space of the LNG storage tank is divided into a plurality of spaces, the LNG storage tank can be operated smoothly by installing one equipment such as a pump, a pump tower and a gas dome utilized for discharging the LNG and boil-off gas loaded in the LNG tank storage. As a result, it is possible to save the manufacturing cost of the LNG storage tank and operate and manage the LNG storage tank easily.
[0056] According to embodiments of the present invention as described above, there can be provided an LNG storage tank in a floating marine structure, wherein a fluid passage is formed in a partition structure so that it is unnecessary to increase the number of equipments to be installed for discharging LNG loaded in the LNG storage tank although an internal space thereof is divided into a plurality of spaces by the partition structure installed for enhancing the strength of the LNG storage tank.
[0057] Therefore, according to embodiments of the present invention, it is possible to save the manufacturing cost of the LNG storage tank and operate and manage easily the LNG storage tank.
[0058] Although a structure of a storage tank for the floating marine structure according to embodiments of the present invention has been described with reference to the drawing, the present invention is not limited to embodiments and drawing illustrated above. It will be apparent that those skilled in the art can make various modifications and changes thereto within the scope of the invention defined by the claims. | Disclosed is a floating marine apparatus including a liquefied natural gas (LNG) tank. The apparatus includes a first LNG containing compartment and a second LNG containing compartment next to the first compartment. The apparatus further includes a bottom passage interconnecting bottom portions of the first and second compartments for fluid communication therebetween. | 5 |
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